Recent Releases of VIC

VIC - VIC 5.1.0

VIC 5.1.0:

VIC 5.1.0 (December 14, 2021)

This is a maintanence release that includes numerous bug fixes and a few model enhancements. All code changes were included in the two release candidates (5.1.0.rc1 and 5.1.0.rc2). See the notes below from the two release candidates for more details.

Announcements

VIC is now shared under the MIT license (GH#917).
Travis-CI was disabled folling the platform's migration to travis-ci.com. See GH#919 for more details (GH918).

VIC 5.1.0 rc2 (September 28, 2020)

Bug Fixes:

Fixed datetime handling bug in unit test module (GH#796)
Removed descriptions of forcing disaggregation options from documentation of classic driver global parameter file (GH#831)
Removed descriptions of forcing disaggregation options from documentation of image driver global parameter file (GH#833)
Fixed segmentation fault in lake model caused by incorrect passing of pointer argument to vic_run(). (GH#826
Relaxed some of the validation of lake parameters, to allow them to be null in cells containing no lakes. (GH#826
Fixed passing of lake data structures to generate_default_lake_state(). (GH#826
Separated the dimensions of arrays related to lake basin shape and of arrays related to the number of lake simulation layers. (GH#826
Added global parameter option to set the maximum number of (dynamic) lake simulation layers. (GH#826
Fixed bug causing ET to be 0 in pure bare soil tiles. (GH#823

VIC 5.1.0 rc1

Release date: (April 27, 2018)

Source code is available here:

This is a minor update from VIC 5.0.1. The VIC 5.1.0 includes new features, such as a new streamflow routing extension and extended parallelization using OpenMP. The release also includes a number of bug fixes for the CESM driver. See the VIC Github page for more details on the changes included in this release.

Model enhancement:

Improved calculation of drainage between soil layers (GH#656)

Drainage from upper layer to adjacent lower layer is calculated according to Brook & Corey curve (where drainage rate is a function of upper-layer soil moisture). In previous versions, a simple numerical solution is applied which uses the timestep-beginning upper-layer soil moisture to calculate drainage rate, and assume this constant rate over the entire timestep. This can cause unreasonably large drainage if the curve has a steep shape and when soil moisture is high. Now, the current version uses exact integral (instead of numerical solution) for layer drainage calculation.
Fixes for the CESM driver
1. GH#642
- Using correct fill value datatypes in MPI Gather steps
- Updated state file name time step to be period-ending rather than period-beginning
- Set the state file name to the RASM case ID
- Removed decimal point for missing values for unsigned integers
- Create dummy forcings when initializing the model (so that there is forcing data for the first time step)
- Changed pressure units from kPa to Pa
- Fixed bug that prevented using the correct local domain grid cells in cesm_put_data.c
- Changed reference temperature units from Celsius to Kelvin in cesm_put_data.c
1. GH#695
- Fix sign for latent heat fluxes passed from VIC to the coupler
- Fix sign for longwave radiation passed from VIC to the coupler
1. GH#696
- Changes names of CESM driver functions trim and advance_time to trimstr and advance_vic_time, respectively, to avoid conflicts with WRF functions with the same names when compiling RFR case.
1. GH#702
- Fixes Julian day for the first timestep in the dmy struct for the CESM driver.
1. GH#710
- Refactor the cesm_put_data.c routine in the CESM driver to use values from out_data directly, rather than computing them separately in cesm_put_data.c.
1. GH#716
- Fixes initialization of coupler fields and calculates temperature and upwelling longwave to pass to WRF during initialization.
1. GH#718
- Updates the cesm_put_data.c routine in the CESM driver to pass gridcell-averaged albedo to the coupler.
1. GH#726
- Updates the cesm_put_data.c routine in the CESM driver to include the correct units for evap passed to the coupler.
1. GH#732
- Updates the cesm_put_data.c routine in the CESM driver to include the correct units for sensible heat flux and updates the rofliq calculation to be correct (previously only OUT_BASEFLOW was being divided by global_param.dt).
1. GH#734
- Updates the cesm_put_data.c routine in the CESM driver to include the correct signs for turbulent heat fluxes and evaporation. Previously we had switched the signs to agree with the image driver and they should instead be in accordance with the sign conventions for coupled models, which differ from those of land surface models. Also, eliminate populating the l2x_Sl_ram1 field with aero_resist to agree with the VIC 4 implementation in RASM.
1. GH#739
- Updates the cesm_put_data.c routine in the CESM driver to include the correct signs for the wind stresses and fixes a bug in calculating friction velocity (previously it was missing a square root).
1. GH#744
- Updates the cesm_interface_c.c routine to include missing timers and the VIC RUN timer in the CESM driver.
1. GH#746
- Updates the cesm_interface_c.c routine in the CESM driver to populate the nrecs, endyear, endmonth and endday fields in the global_param struct to make them available to vic_finalize for timing tables (specifically the secs/day columns).
1. GH#800
- Updates the default namelist settings for the CESM driver to include output filenames consistent with the RASM naming conventions, default thermal nodes to 10, FULL_ENERGY to TRUE, and sets defaults for daily and monthly mean output.
1. GH#866
- Updates the default output variables for the CESM driver. Also updates the VIC5 parameter file location to be the RASM inputdata directory and updates the name of the VIC5 parameter file to the new VIC5 parameters.
1. GH#869
- Adds support to the CESM driver for 25km resolution RASM runs.
1. GH#871
- Adds initial state files to default 50km and 25km builds so that these are used by other groups running RASM rather than VIC5 starting up from a clean start.
1. GH#880
  --Adds option STATENAME_CESM to the option_struct so that statefiles in the CESM driver can be in accordance with RASM naming conventions for model components.
Speed up NetCDF operations in the image/CESM drivers (GH#684)

These changes speed up image driver initialization, forcing reads, and history writes by only opening and closing each input netCDF file once.
Added two new timers to measure time in I/O operations (GH#703)

These two timers count the CPU and WALL time spent in vic_force and vic_write. The accumulated time from these timers is printed out at the end of each simulation in the timing table. See also GH#442.
Added gridcell-averaged albedo (STATE_AVG_ALBEDO) as a state file variable (GH#712)

This is for use in the CESM driver for VIC to pass to WRF, but has been implemented in the core structure of VIC (in vic_run) for consistency with the classic and image drivers. Running VIC from a cold start now also includes calculation of gridcell-averaged albedo.
Cleanup of the initialization sections of the image and cesm drivers (GH#701)

Codified behavior in the initialization of the image and cesm drivers that requires the parameter variables AreaFract, Pfactor, zone_fract, and Cv must sum exactly to 1.0. If using the SNOW_BAND option, the area weighted elevation must match the mean grid cell elevation (elev). VIC will print warnings if any of these criteria are violated.
Added thread parallelization using OPENMP (GH#712)

The VIC image and CESM drivers now may be optionally compiled with OPENMP to enable shared memory thread parallelization. This option should improve the parallel scaling of these drivers by reducing the number of MPI messages and increasing message size.
Added streamflow routing extensions ROUT_STUB and ROUT_RVIC for the VIC image driver (GH#231)

The VIC image driver can be optionally compiled with ROUT_RVIC to enable routing in image mode (ROUT_STUB is the default extension which means no routing). With ROUT_RVIC enabled, the output variable OUT_DISCHARGE is available, and there will also be an extra state variable STATE_ROUT_RING stored in the state file.
Moved MAX_ITER_GRND_CANOPY, which controls the maximum number of ground-canopy iterations in CLOSE_ENERGY mode for vegetation types with an overstory, to the parameters struct (GH#771)

Previously this was set in the surface_fluxes.c numerics routine for ground-canopy iterations, which meant that that routine had to be altered to change the maximum number of iterations. It has now been moved to the parameters struct so that it can be overriden in the constants file.
Updated new snow density function by adding a cap to new snow density that is set in the parameters struct by the parameter SNOW_NEW_SNOW_DENS_MAX (GH#776)

Previously the change in cold content of the snowpack term (deltaCC in the snow_data_struct) would get unreasonably large if the Hedstrom and Pomeroy 1998 equation used to calculate snow density, which depends only on air temperature, was calculated with air temperatures above about 2 deg C. We use this term to calculate the ground flux from the snowpack and snow depth, which resulted in extremely small snow depths and unreasonably large ground fluxes from the snowpack (and thus changes in snowpack cold content). Now there is a cap on new snow density with the new parameter SNOW_NEW_SNOW_DENS_MAX as well as a snow depth below which we disregard the ground flux from the snowpack (1.e-8).
Added new option BULK_DENSITY_COMB that enables soil bulk density (mineral and organic) to be read from the parameters file (GH#817)

The option BULK_DENSITY_COMB enables soil bulk density (mineral and organic) to be read in as a parameter when the option is set to true in the global parameter file. Default is false.
Turns on ORGANIC_FRACT option that previously existed in VIC 4 and enables the BULK_DENSITY_COMB option to be used in conjunction with it (GH#837)

The option ORGANIC_FRACT, if set to True, means that the organic fraction of the soil, soil density of the organic matter, and bulk density of the organic matter (if BULK_DENSITY_COMB is set to false) will be read in from the parameter file. If BULK_DENSITY_COMB is set to True, the bulk density of the organic matter will not be read in separately. Default is false.
Added new option MAX_SNOW_ALBEDO that enables new snow albedo to be read in from the parameters file (GH#835)

The option MAX_SNOW_ALBEDO, if set to true in the global parameter file, means that new snow albedo will be read in from the parameter file and used in the snow routines for all vegetation types except for bare soil.
Miscellaneous clean-up:

GH#723
- Added support for veg_hist forcings (non-climatological) in image mode
- Fixed erroneous allocation of extra veg tile in image mode
- Simplified looping over veg tiles and bands in vic_run() and prepare_full_energy()
- Replaced lengthy data structures with local pointers in vic_run()
- Simplified out_prec, out_rain, and Melt arrays
- Updated names of variables and options for LAI and FCANOPY in documentation to match their new names in the code
- Removed constants MAX_VEG and MAX_BANDS from code; all arrays that were declared with those lengths were replaced with dynamic allocations. This allowed for specification of veg libraries containing more classes without recompiling the code, and more efficient memory usage.
GH#766
- Improved logic in computing soil evaporation (esoil), primarily in func_surf_energy_bal(), by creating explicit terms for transpiration (transp) and esoil in the layer data structure.

Bug Fixes:

NetCDF forcing files are now closed at the last timestep in stead of after the last timestep. (GH#774)
Renamed "fcov" to "fcan" in image driver to better match variable code name (GH#673)

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 3 years ago

VIC - VIC.5.1.0.rc2

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 4 years ago

VIC - VIC 5.1.0.rc1

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman about 7 years ago

VIC - VIC 5.0.1

VIC 5.0.1:

Release date: (February 1, 2017)
This release contains a number of bug fixes.

Bug Fixes:

Fixed image driver history file name timestamp (GH#635)

After the fix, the timestamp appeared in the image driver output history filename is the beginning time of the time period in the file.
Fixed forceskip rounding bug (GH#639)

After the fix, the forceskip variable in the global parameter structure (i.e., the number of timesteps to skip in the forcing data for the simulatin period) is rounded correctly (before the fix, rounding error might cause 1-timestep offset in the simulation results).
Fixed a problem with image restarts when using multiple processors (GH#638)

After the fix, only the master node is assigned the task of validating state file dimensions and coordinate variables. Multiprocessing was also added to the VIC testing framework.
Ensured that the mask variable in the input domain file must be integer type; otherwise an error is raised. (GH#645)
Fixed a bug related to make_lastday function (GH#647)

Before the fix, the input arguments to function make_lastday are sometimes in a wrong order. The bug caused error when trying to write state file on a leap day.
Fixed a bug related to writing two-dimensional lat/lon variables to a state file (GH#652)

Before the bug fix, two-dimensional lat/lon variables were not populated correctly and were written as fill values to a state file. Now two-dimensional lat/lon variables are correctly populated and written.
Fixed a bug related to dz_node and node_depth variables in image driver output state file (GH#657)

Before the fix, dz_node and node_depth in image driver output state file were not spatially distributed, which was wrong. Now these two variables are spatially distributed in the output state file.
Fixed a bug related to run_cell and mask variables in image driver inputs (GH#662)

Before the fix, active cell was controlled by mask variable in the domain file in image driver, and run_cell variable in the parameter file was not actually used. Now run_cell variable in the parameter file controls active cells (run_cell must be within the mask defined by the domain file).
Fixed a time precision bug for long simulations (GH#668)

Before the fix, the timestamps of long VIC runs were incorrect in some cases due to precision issue in timestamp generation. This resulted in incorrect output timestamps after running for a long period of time, or output termination. Please refer to GH#668 for details on this bug fix.
Fixed a bug related to forcing and simulation start time (GH#671)

Before the fix, there would be an error if the simulation start time is later than the forcing start time that year AND the simulation spans multiple years. Fixed this bug.

Hydrosphere - Freshwater and Hydrology - C
Published by yixinmao about 8 years ago

VIC - VIC.5.0.0

VIC 5.0.0

Release date: (September 2, 2016)

Source code is available here:

This is a major update from VIC 4. The VIC 5.0.0 release aims to have nearly identical physics as VIC 4.2 while providing a clean, refactored code base supporting multiple drivers. There are a number of new features, bug fixes, and backward incompatible changes. See the VIC Github page for more details on the changes included in this release.

New Features:

"vic_run" (GH#7)

Although the physics and model behavior of VIC 5.0.0 should be nearly identical to VIC 4.2, the source code has undergone a major cleanup and reorganization. We have separated the physical core ("vic_run") from the driver source code. This work has improved the extensibility and readability of the model.
Classic Driver (GH#7)

The Classic Driver provides similar functionality as VIC 4, including ASCII and binary I/O, and a time-before-space evaluation loop order. The Classic Driver is maintained for two main reasons:
1. to provide some level of backward compatibility for existing VIC users that wish to continue using VIC using a traditional approach, and,
2. to allow VIC to be run at individual grid cells, without requiring the infrastructure needed by the Image Driver. Documentation for the Classic Driver can be found here.
Image Driver (GH#7)

The Image Driver adds a number of features to the user interface of the VIC model. Most notably, it uses a space-before-time evaluation loop order, netCDF I/O, and parallelization using MPI. Image Driver specific documentation can be found here.
Constants File (GH#192)

Earlier versions of VIC included many hard-coded parameters and constants. We have consolidated these constants into a single structure and developed an input file that allows users to modify parameters at run-time. See here for more information.
Logging (GH#173)

A set of logging Macros have been added to all drivers and vic_run. The logging level can be set in the driver Makefile via the LOG_LVL variable. The logging Macros provide the filename and line number in the source code to aid in debugging. Additionally, when compiler support is available, a traceback is printed when VIC exits during runtime. When the LOG_DIR variable is provided in the global parameter file, VIC will write its log(s) to log files instead of printing to stdout.
Sub-hourly Timestep (GH#188)

Previous versions of VIC were limited to a minimum timestep of one hour. The units of the VIC timestep have been changed from hours to seconds and the minimum timestep is now one second. If you intend on running VIC at a timestep of less than one hour, we suggest extensive testing.
Calendar Support (GH#188)

Earlier versions of VIC used the standard Gregorian calendar. Because many modern climate models use non-standard calendars, we have implemented all CF compliant calendars. The standard Gregorian calendar remains the VIC default. See the documentation for individual drivers for how to set the calendar option (e.g. classic.
Sample Datasets (GH#387)

The VIC_sample_data repository contains the necessary input datasets (forcings and parameters) to run short simulations of the VIC model for both the classic and image driver.
Tests Datasets (GH#79)

See https://github.com/UW-Hydro/VIC/issues/79 for more information. A temporary location of the test data is here: ftp://ftp.hydro.washington.edu/pub/gergel/VIC5_test_data/
Testing and Continuous Integration (GH#190)

A comprehensive testing platform has been implemented and is available for public use along with the VIC model. A small subset of the test platform is run on Travis-CI, which facilitates continuous integration of the VIC test platform. More information on the test platform is here.
Run-time profiling and timing (GH#442)

A timing module has been added to VIC in order to assess the computational cost and throughput of the VIC model. New output variables (OUT_TIME_VICRUN_WALL and OUT_TIME_VICRUN_CPU) document the time spent in vic_run for each variable. Additionally, a timing table is printed to LOG_DEST at the end of each simulation.

Backwards Incompatible Changes:

Classic Driver I/O Formatting (GH#18, GH#204, GH#227)

The format of ASCII forcing and output files has changed in VIC 5. These changes were motivated by the desire to improve simulation metadata tracking and reproducibility of VIC simulations.

Output files now include a header with simulation metadata and variable names. The PRT_HEADER option has been deprecated.

Classic Driver Global Parameter Options

A number of global parameter options have changed for the Classic Driver, relative to VIC 4.

TIME_STEP (int, units: hours) has been changed to MODEL_STEPS_PER_DAY (int)
SNOW_STEP (int, units: hours) has been changed to SNOW_STEPS_PER_DAY (int)
OUT_DT (int, units: hours) has been changed to OUTPUT_STEPS_PER_DAY (int)
FORCE_DT (int, units: hours) has been changed to FORCE_STEPS_PER_DAY (int)
BINARY_STATE_FILE (TRUE or FALSE) has been changed to STATE_FORMAT (BINARY or ASCII)
BINARY_OUTPUT (TRUE or FALSE) has been changed to OUT_FORMAT (BINARY or ASCII)

State files now include seconds (GH#464)

There is a new global parameter option, STATESEC. This specifies the time step at the end of which state will be saved, in units of seconds. In other words, if you have an hourly time step (3600 sec) and you want to save state at the end of the final time step of the day (which is 86400 seconds long), subtract 3600 from 86400 to get a STATESEC of 82800. This corresponds to the first second of the final time step. State will be saved at the end of that time step.
When the state save date is appended to state filenames, STATESEC will be included so that the date will have the format YYYYMMDD_SSSSS.

Classic Driver Output Variables (GH#352)

Computation of potential evapotranspiration (PET) has been simplified, reducing the number of output variables from 6 to 1. The following output variables have been removed:

OUT_PET_SATSOIL (potential evapotranspiration from saturated bare soil)
OUT_PET_H2OSURF (potential evapotranspiration from open water)
OUT_PET_SHORT (potential evapotranspiration (transpiration only) from short reference crop (grass))
OUT_PET_TALL (potential evapotranspiration (transpiration only) from tall reference crop (alfalfa))
OUT_PET_NATVEG (potential evapotranspiration (transpiration only) from current vegetation and current canopy resistance)
OUT_PET_VEGNOCR (potential evapotranspiration (transpiration only) from current vegetation and 0 canopy resistance)

These have been replaced by:

OUT_PET (potential evapotranspiration, which = area-weighted sum of potential transpiration and potential soil evaporation; potential transpiration is computed using the Penman-Monteith equation with architectural resistance and LAI of the current veg cover)

Deprecated Features:

Removed unused global parameter option MEASURE_H (GH#284)
Removed MTCLIM (GH#288)

Previous versions of VIC used MTCLIM to generate missing forcing variables required to run VIC. This led to confusion by many users and considerably more complex code in the Classic Driver. VIC forcings are now required to be provided at the same time frequency as the model will be run at (SNOW_STEPS_PER_DAY).

As part of this change, the following options have been removed from the Classic Driver:

LW_TYPE
LW_CLOUD
MTCLIM_SWE_CORR
VP_INTERP
VP_ITER
OUTPUT_FORCE

As part of this change, the following output variables have been removed from the Classic Driver:

OUT_COSZEN
OUT_TSKC

In the future, we would like to provide a stand-alone version of MTCLIM that produces subdaily meteorological forcings. We are looking for community support for this feature (GH#17)
3. Removed LONGWAVE and SHORTWAVE forcing types (GH#379).

Previous versions of VIC allowed users to specify either LONGWAVE or LWDOWN to denote the incoming longwave radiation flux and SHORTWAVE or SWDOWN to denote the incoming shortwave radiation flux. We have removed these duplicate options, standardizing on the more descriptive LWDOWN and SWDOWN.

Similarly, output variables OUT_NET_LONG and OUT_NET_SHORT have been replaced with OUT_LWNET and OUT_SWNET, respectively.
4. Changed the name of the variable VEGCOVER to FCANOPY, since this more accurately captures the meaning of the term (i.e., the fractional area of the plant canopy within the veg tile). Similarly changed OUT_VEGCOVER to OUT_FCANOPY.

Similarly, changed the names of the following global parameter file options:

VEGLIB_VEGCOVER --> VEGLIB_FCAN
VEGPARAM_VEGCOVER --> VEGPARAM_FCAN
VEGCOVER_SRC --> FCAN_SRC

Bug Fixes:

Miscellaneous fixes to lake module (GH#425)

Several lake processes (aerodynamic resistance, albedo, latent/sensible heat fluxes, net radiation, etc) were reported incorrectly or not at all in output files. This has been fixed. In addition, in the absence of an initial state file, lake temperatures were initialized to unrealistic temperatures (the air temperature of the first simulation time step). To fix this, we now initialize the lake temperature to annual average soil temperature.
Fix for computation of soil layer temperatures when soil thermal nodes do not reach the bottom of the soil column. (GH#467)

Previously, if the soil thermal damping depth was shallower than the bottom of the deepest soil layer, and FROZEN_SOIL==TRUE, VIC would abort when estimating layer ice contents because it could not estimate a layer temperature if the thermal nodes did not completely span the layer. Now, a layer temperature is estimated even when thermal nodes do not completely span the layer, and the error no longer occurs.
Fix related to exact restart (GH#481, GH#507, GH#509)

Previously, VIC did not produce the same results (fluxes and states) if a simulation was separated into multiple shorter-period runs by saving the state variables and restarting. This was due to:
1. The MTCLIM algorithm resulted in slightly different sub-daily meteorological variable values for different lengths of forcings (MTCLIM is deprecated in the current version)
2. A few bugs resulting in inexact restart. The following bugs have been fixed:
  - The prognostic state variable energy.Tfoliage (foliage temperature) is now saved to the state file
  - Two flux variables energy.LongUnderOut and energy.snow_flux are now saved to the state file.
    
    !!!Note
    This is a temporary solution to ensure exact restart. A better way of handling these two flux variables needs to be done in the future (see GH#479)
Fix for binary state file I/O (GH#487)

Fixed a bug so that the binary format state file I/O works correctly.
Fix for a physical constant (water heat capacity) (GH#574)

Fixed a bug where volumetric heat capacity of water should be used in func_canopy_energy_bal (previously specific heat capacity was used).

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 8 years ago

VIC - VIC.5.0.0.rc2

This is the second release candidate of VIC 5.0.0.

Major new features in the VIC 5 series, compared to VIC 4

"vic_run" (GH#7)

Although the physics and model behavior of VIC 5.0.0 should be nearly identical to VIC 4.2, the source code has undergone a major cleanup and reorganization. We have separated the physical core ("vic_run") from the driver source code. This work has improved the extensibility and readability of the model.
Classic Driver (GH#7)

The Classic Driver provides similar functionality as VIC 4, including ASCII and binary I/O, and a time-before-space evaluation loop order. The Classic Driver is maintained for two main reasons:
1. to provide some level of backward compatibility for existing VIC users that wish to continue using VIC using a traditional approach, and,
2. to allow VIC to be run at individual grid cells, without requiring the infrastructure needed by the Image Driver. Documentation for the Classic Driver can be found here.
Image Driver (GH#7)

The Image Driver adds a number of features to the user interface of the VIC model. Most notably, it uses a space-before-time evaluation loop order, netCDF I/O, and parallelization using MPI. Image Driver specific documentation can be found here.
Constants File (GH#192)

Earlier versions of VIC included many hard-coded parameters and constants. We have consolidated these constants into a single structure and developed an input file that allows users to modify parameters at run-time. See here for more information.
Logging (GH#173)

A set of logging Macros have been added to all drivers and vic_run. The logging level can be set in the driver Makefile via the LOG_LVL variable. The logging Macros provide the filename and line number in the source code to aid in debugging. Additionally, when compiler support is available, a traceback is printed when VIC exits during runtime. When the LOG_DIR variable is provided in the global parameter file, VIC will write its log(s) to log files instead of printing to stdout.
Sub-hourly Timestep (GH#188)

Previous versions of VIC were limited to a minimum timestep of one hour. The units of the VIC timestep have been changed from hours to seconds and the minimum timestep is now one second. If you intend on running VIC at a timestep less that one hour, we suggest significant testing.
Calendar Support (GH#188)

Earlier versions of VIC used the standard Gregorian calendar. Because many modern climate models use non-standard calendars, we have implemented all CF compliant calendars. The standard Gregorian calendar remains the VIC default. See the documentation for individual drivers for how to set the calendar option (e.g. classic).
Sample Datasets (GH#387)

The VIC_sample_data repository contains the necessary input datasets (forcings and parameters) to run short simulations of the VIC model for both the classic and image driver.
Tests Datasets (GH#79)

See https://github.com/UW-Hydro/VIC/issues/79 for more information. A temporary location of the test data is here: ftp://ftp.hydro.washington.edu/pub/gergel/VIC5_test_data/
Testing and Continuous Integration (GH#190)

A comprehensive testing platform has been implemented and is available for public use along with the VIC model. A small subset of the test platform is run on Travis-CI, which facilitates continuous integration of the VIC test platform. More information on the test platform is here
Run-time profiling and timing (GH#442)

A timing module has been added to VIC in order to assess the computational cost and throughput of the VIC model. New output variables (OUT_TIME_VICRUN_WALL and OUT_TIME_VICRUN_CPU) document the time spent in vic_run for each variable. Additionally, a timing table is printed to LOG_DEST at the end of each simulation.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 8 years ago

VIC - VIC.5.0.0.rc1

This is the first release candidate of VIC 5.0.0.

Major new features in the VIC 5 series, compared to VIC 4

"vic_run" (GH#7)

Although the physics and model behavior of VIC 5.0.0 should be nearly identical to VIC 4.2, the source code has undergone a major cleanup and reorganization. We have separated the physical core ("vic_run") from the driver source code. This work has improved the extensibility and readability of the model.
Classic Driver (GH#7)

The Classic Driver provides similar functionality as VIC 4, including ASCII and binary I/O, and a time-before-space evaluation loop order. The Classic Driver is maintained for two main reasons:
1. to provide some level of backward compatibility for existing VIC users that wish to continue using VIC using a traditional approach, and,
2. to allow VIC to be run at individual grid cells, without requiring the infrastructure needed by the Image Driver. Documentation for the Classic Driver can be found here.
Image Driver (GH#7)

The Image Driver adds a number of features to the user interface of the VIC model. Most notably, it uses a space-before-time evaluation loop order, netCDF I/O, and parallelization using MPI. Image Driver specific documentation can be found here.
Constants File (GH#192)

Earlier versions of VIC included many hard-coded parameters and constants. We have consolidated these constants into a single structure and developed an input file that allows users to modify parameters at run-time. See here for more information.
Logging (GH#173)

A set of logging Macros have been added to all drivers and vic_run. The logging level can be set in the driver Makefile via the LOG_LVL variable. The logging Macros provide the filename and line number in the source code to aid in debugging. Additionally, when compiler support is available, a traceback is printed when VIC exits during runtime. When the LOG_DIR variable is provided in the global parameter file, VIC will write its log(s) to log files instead of printing to stdout.
Sub-hourly Timestep (GH#188)

Previous versions of VIC were limited to a minimum timestep of one hour. The units of the VIC timestep have been changed from hours to seconds and the minimum timestep is now one second. If you intend on running VIC at a timestep less that one hour, we suggest significant testing.
Calendar Support (GH#188)

Earlier versions of VIC used the standard Gregorian calendar. Because many modern climate models use non-standard calendars, we have implemented all CF compliant calendars. The standard Gregorian calendar remains the VIC default. See the documentation for individual drivers for how to set the calendar option (e.g. classic).
Sample Datasets (GH#387)

The VIC_sample_data repository contains the necessary input datasets (forcings and parameters) to run short simulations of the VIC model for both the classic and image driver.
Tests Datasets (GH#79)

TODO: See https://github.com/UW-Hydro/VIC/issues/79 for more information.
Testing and Continuous Integration (GH#190)

A comprehensive testing platform has been implemented and is available for public use along with the VIC model. A small subset of the test platform is run on Travis-CI, which facilitates continuous integration of the VIC test platform. More information on the test platform is here

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman almost 9 years ago

VIC - VIC 4.2.d

VIC 4.2.d (20 June 2016)

This release contains a number of bug fixes.

Bug Fixes

Fixed uninitialized dmy_struct when OUTPUT_FORCE==TRUE and BINARY_OUTPUT==TRUE (#393)
Fixed uninitialized vegetation parameters when VEGPARAM_LAI==FALSE (#455)

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman almost 9 years ago

VIC - VIC 4.2.c

VIC 4.2.c (12 December 2015)

This release contains a number of bug fixes.

Bug Fixes

Fixed water balance errors in lake model (#308, #316)
Fixed OUTPUT_FORCE behavior related to veg_hist features (#305, #307)
Updated bare soil evaporation behavior related to veg_hist update from 4.2 (#306, #315)

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 9 years ago

VIC - Release of VIC.4.2.b

* Description of changes between VIC 4.2.a and VIC 4.2.b *

Bug Fixes:

Fixed memory error in initialize atmos when OUTPUT_FORCE = TRUE.

Files Affected:

initialize_atmos.
Makefile

Description:

Previously, access to unitialized elements of the veg_con and veg_hist
structure was attempted when OUTPUT_FORCE = TRUE, causing a memory error
and the model to crash.  This fix sets these elements inside a
`if (!options.OUTPUT_FORCE)` block allowing the OUTPUT_FORCE option to
work as expected.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 10 years ago

VIC - Release of VIC.4.2

Description of changes between VIC 4.1.2 and VIC 4.2

New Features:

Added partial vegetation cover (within each tile).

Files Affected:

alloc_veg_hist.c
calc_veg_params.c
display_current_settings.c
full_energy.c
func_surf_energy_bal.c
get_force_type.c
get_global_param.c
global.h
initialize_atmos.c
initialize_global.c
initialize_veg.c
output_list_utils.c
put_data.c
read_atmos_data.c
read_forcing_data.c
read_veglib.c
read_vegparam.c
solve_snow.c
surface_fluxes.c
vicNl_def.h
vicNl.h

Description:

Added a time-varying (non-climatological) partial vegcover fraction
within vegetated tiles.  Previously, vegetation was assumed to
cover 100% of the land surface in a vegetated tile (i.e., "big
leaf" scheme).  This assumption is not valid in general, and in
particular becomes very inaccurate in arid environments (e.g., open
shrublands), or as LAI decreases to near 0.  In such cases,
evaporation from bare soil between the plants becomes a major (or
dominant) component of total evapotranspiration.

This partial veg cover fraction ("vegcover") is treated the same way
as LAI and albedo: new options (VEGCOVER_SRC and VEGPARAM_VEGCOVER)
tell VIC whether the veg param file contains 12 climatological
vegcover values and whether to use those or the ones in the veg
library.  A new forcing variable ("VEGCOVER") can be included in
forcing files along with LAI and albedo, and must be specified in the
global parameter file in the same way.  There is an additional option
controlling whether VEGCOVER values appear in the veg library file:
VEGLIB_VEGCOVER.  FALSE by default, if TRUE it tells VIC to expect 12
monthly VEGCOVER values in each veg class, after the 12 LAI and before
the 12 albedo values.

Internally, VIC uses the partial vegcover fraction to divide each veg
tile into the area covered by plants and the area in between the
plants.  LAI and canopy moisture and snow storage are rescaled by
1/vegcover to get plant-specific values before canopy evap,
transpiration, and canopy snow dynamics are computed (vegcover is not
allowed to go below the value MIN_VEGCOVER in vicNl_def.h).  Bare soil
evap is computed for the bare soil component of the tile.  Total
evapotranspiration is computed as the area-weighted sum of canopy evap
and transpiration from the vegetated fraction and bare soil evap from
the bare soil fraction.  Finally, LAI and canopy moisture storage are
rescaled back to the tile-area-average values before output.

Added non-climatological time-varying veg parameters.

Files Affected:

alloc_veg_hist.c (new)
calc_surf_energy_bal.c
canopy_evap.c
display_current_settings.c
full_energy.c
func_surf_energy_bal.c
get_force_type.c
get_global_param.c
initialize_atmos.c
initialize_global.c
initialize_veg.c
Makefile
output_list_utils.c
penman.c
put_data.c
read_atmos_data.c
read_forcing_data.c
read_veglib.c
read_vegparam.c
snow_intercept.c
solve_snow.c
surface_fluxes.c
vicNl.c
vicNl_def.h
vicNl.h

Description:

Added ability to read timeseries of LAI and albedo as forcing
variables.  In addition, climatological albedo values can now be
given in the veg parameter file in a similar manner to LAI.

These changes involved adding a new veg_hist data structure to
contain the timeseries of LAI, Wdmax, and albedo, as well as
adding LAI, Wdmax, and albedo variables to the veg_var structure
to store the current values of these variables.

To allow for climatological albedo values to be specified in the
veg parameter file (similar to LAI), a new option has been introduced:
ALB_SRC.  The constants LAI_FROM_VEGPARAM and LAI_FROM_VEGLIB have
changed name to FROM_VEGPARAM and FROM_VEGLIB so that they can be
used to specify the source of either variable.

VIC now handles LAI and albedo as follows:
1. If specified as a variable in one of the forcing files, the
values from the forcing file will be used in the simulation instead
of the values in the veg parameter or veg library files.
2. If not specified as a variable in one of the forcing files,
values will be taken from the veg parameter file if a) they are listed
there and b) LAI_SRC (for LAI) and/or ALB_SRC(for albedo) are set to
FROM_VEGPARAM.
3. If not supplied as a forcing and [EITHER not listed in the veg
parameter file OR listed there but LAI_SRC or ALB_SRC is set to
FROM_VEGLIB], values will be taken from the veg library.

New forcing variables for carbon cycle.

Files Affected:

alloc_atmos.c
compute_coszen.c (new)
get_force_type.c
initialize_atmos.c
Makefile
mtclim_constants_vic.h
mtclim_vic.c
mtclim_wrapper.c
output_list_utils.c
put_data.c
vicNl_def.h
vicNl.h
write_forcing_file.c

Description:

Added the following new input forcing variables (used for simulations
of carbon cycle processes):
  CATM: Atmospheric CO2 mixing ratio [ppm]
  FDIR: Fraction of incoming shortwave that is direct [fraction]
  PAR:  Photosynthetically active radiation [W/m2]

These variables are optional; if not supplied as forcings, VIC will use
default values for them, as follows:
  CATM: Value of CatmCurrent defined in vicNl_def.h
  FDIR: Value computed by MTCLIM module
  PAR:  SHORTWAVE*SW2PAR, with SW2PAR defined in vicNl_def.h

Similarly, added the following new output variables:
  OUT_CATM:   (equals CATM)
  OUT_COSZEN: Cosine of the solar zenith angle, computed by MTCLIM module
  OUT_FDIR:   (equals FDIR)
  OUT_PAR:    (equals PAR)

Added simulation of photosynthesis.

Files Affected:

calc_Nscale_factors.c (new)
calc_surf_energy_bal.c
canopy_assimilation.c (new)
canopy_evap.c
display_current_settings.c
faparl.c (new)
free_dist_prcp.c
free_vegcon.c
full_energy.c
func_canopy_energy_bal.c
func_surf_energy_bal.c
get_global_param.c
initialize_global.c
initialize_veg.c
Makefile
make_veg_var.c
output_list_utils.c
penman.c
photosynth.c (new)
put_data.c
read_soilparam.c
read_veglib.c
read_vegparam.c
snow_intercept.c
solve_snow.c
surface_fluxes.c
vicNl_def.h
vicNl.h

Description:

Added simulation of photosynthesis.  The photosynthesis formulation was
taken from the BETHY model (Knorr, 2000), which in turn used the Farquhar
model for C3 plants and the Collatz model for C4 plants.  In addition,
inhibition of photosynthesis under saturated conditions (as described
by Frolking et al, 2002) is allowed for.

This feature requires several new veg parameters to be in the veg
library file:
  Ctype:          Photosynthetic pathway; can be C3 or C4
  MaxCarboxRate:  Maximum carboxlyation rate at 25 deg C (mol(CO2)/m2s)
  MaxETransport:  Maximum electron transport rate at 25 deg C (mol(CO2)/m2s) (C3 plants)
  CO2Specificity: CO2 specificity at 25 deg C (mol(CO2)/m2s) (C4 plants)
  LightUseEff:    Light-use efficiency (mol(CO2)/mol(photons))
  NscaleFlag:     TRUE = nitrogen-scaling factors are applicable to this veg class
  Wnpp_inhib:     Moisture level (fraction of maximum moisture) above which photosynthesis experiencing saturation inhibition, i.e. too wet for optimal photosynthesis; only applies to top soil layer
  NPPfactor_sat:  Photosynthesis multiplier (fraction of maximum) when top soil layer is saturated

There are several new output variables associated with this feature:
  OUT_GPP:  Gross primary productivity [g C/m2d]
  OUT_RAUT: Autotrophic respiration [g C/m2d]
  OUT_NPP:  Net primary productivity [g C/m2d]
  OUT_APAR: Absorbed PAR [W/m2]

By default, this feature is turned off.  To turn this feature on, set
CARBON to TRUE in the global parameter file.

When this feature is turned on, you can choose to compute stomatal
resistance via the Jarvis formulation (the formulation used by all
previous versions of VIC) or as a function of photosynthetic demand.
This is determined by the setting of RC_MODE in the global parameter
file.  A value of RC_JARVIS (which is the default) selects the Jarvis
formulation.  A value of RC_PHOTO selects the photosynthetic demand
formulation.

Added simulation of soil carbon storage and fluxes.

Files Affected:

compute_soil_resp.c (new)
full_energy.c
initialize_lake.c
initialize_soil.c
initialize_veg.c
LAKE.h
lakes.eb.c
Makefile
output_list_utils.c
put_data.c
read_initial_model_state.c
soil_carbon_balance.c (new)
surface_fluxes.c
vicNl_def.h
vicNl.h
write_model_state.c

Description:

Added simulation of soil carbon storage and fluxes.  This formulation was
taken mostly from the LPJ model (Sitch, 2003), which in turn used a
Lloyd-Taylor model for the dependence of soil respiration on soil
temperature.  The dependence of soil respiration on soil moisture was
based on the formulation of Yi et al (2012) but modified to allow a small
respiration rate under saturated conditions.

At this point, we do not simulate the storage of carbon in living biomass.
Therefore, the flux of carbon into the soil (litterfall) is set equal to
the total NPP of the previous calendar year, spread evenly over the current
year.  As in the LPJ model, soil carbon is stored in 3 pools: litter (fast),
intermediate, and slow; with associated turnover times of 2.86 y, 33.3 y, and
1,000 y, respectively.  Litterfall enters the litter pool.  Carbon exits the
litter pool through respiration (RhLitter).  A fraction (fAir) of this
respired carbon is in the form of CO2 and is vented directly to the atmosphere
(RhLitter2Atm).  The remainder is sent to the intermediate and slow pools
in the proportions fInter and (1-fInter), respectively.  These pools also
respire carbon, which is assumed to be in the form of CO2 and vented directly
to the atmosphere.

There are several new output variables associated with this feature:
  OUT_RHET: Total heterotrophic respiration vented to the atmosphere
            (= RhLitter2Atm+RhInter+RhSlow)  [g C/m2d]
  OUT_NEE:  Net Ecosystem Exchange (= NPP-RHET) [g C/m2d]
  OUT_LITTERFALL: Flux of carbon from living biomass into litter pool [g C/m2d]
  OUT_CLITTER: Carbon density in the litter pool [g C/m2]
  OUT_CINTER: Carbon density in the intermediate pool [g C/m2]
  OUT_CSLOW: Carbon density in the slow pool [g C/m2]

This feature is part of the carbon cycle, controlled by the setting of the
CARBON option in the global parameter file.

Added soil moisture content for half-space below bottom soil layer

Files Affected:

soil_conduction.c
vicNl_def.h

Description:

VIC's soil thermal profile can extend well below its soil hydrologic
layers.  Previously, the moisture content of these soil thermal nodes
was set to that of the bottom soil layer.  Now, the moisture content can
be set to a user-specified value, SLAB_MOIST_FRACT, defined in
vicNl_def.h.

Removed the DIST_PRCP option.

Files Affected:

arno_evap.c
calc_rainonly.c
calc_snow_coverage.c
calc_surf_energy_bal.c
canopy_evap.c
display_current_settings.c
dist_prec.c (removed)
free_all_vars.c (renamed from free_dist_prcp.c)
frozen_soil.c
full_energy.c
func_canopy_energy_bal.c
func_surf_energy_bal.c
get_global_param.c
initialize_global.c
initialize_model_state.c
initialize_new_storm.c (removed)
LAKE.h
lakes.eb.c
make_all_vars.c (renamed from make_dist_prcp.c)
Makefile
prepare_full_energy.c
put_data.c
read_initial_model_state.c
read_soilparam.c
redistribute_during_storm.c (removed)
runoff.c
snow_intercept.c
soil_conduction.c
snow_intercept.c
solve_snow.c
surface_fluxes.c
vicNl.c
vicNl_def.h
vicNl.h
write_forcing_file.c
write_model_state.c

Description:

Removed the DIST_PRCP option and all functions and variables associated
with it.  Removed the "dist" array dimension from the cell and veg_var
data structures.  Renamed the "dist_prcp" data structure to
"all_vars".

Bug Fixes:

Fixed division by 0 and nans in output when there is no liquid water available
to satisfy evaporative demand

Files Affected:

runoff.c

Description:

Previously, runoff() scaled estimated evaporation for each frost subarea
by that subarea's portion of available liquid moisture, via summing
available liquid moisture over all subareas and computing the ratio of
each subarea's moisture to the sum.  There was no check on whether the
sum > 0, resulting in the possibility of division by 0 when no liquid
moisture is available.  This has been fixed (a check was added).  In
addition, the apportionment of evaporation to subareas originally
included a check on whether all of the evaporative demand was met,
with a warning statement if not.  This check and warning have been
removed, since the evaporation values are subsequently modified to
reflect what actually evaporated (i.e. it's ok for the initial
estimate to exceed available moisture without affecting the water
balance).

Fixed negative liquid soil moisture for bare soil conditions

Files Affected:

runoff.c

Description:

Previously, runoff() only checked whether total (liquid+ice) soil
moisture was > residual moisture, but not whether liquid soil moisture
was positive.  In some cases, in the bare soil tile, liquid soil
moisture could occasionally go negative.  This has been fixed by adding
a check on liquid soil moisture to runoff().

Fixed incorrect handling of case of a mix of cells with and without lakes.

Files Affected:

initialize_model_state.c
read_lakeparam.c

Description:

VIC was neither reading the lake parameter file correctly nor
initializing the lake data structures correctly for the case of a
mix of cells with and without lakes within a single lake parameter
file.  This has been fixed.

Fixed use of tmp_moist array without initialization.

Files Affected:

initialize_model_state.c

Description:

Fixed use of tmp_moist array without initialization.

Fix for crash when FROZEN_SOIL, EXP_TRANS and IMPLICIT all == TRUE

Files Affected:

frozen_soil.c
func_surf_energy_bal.c
vicNl.h

Description:

Extended the "cold nose" hack to the "warm nose" condition, and also
extended to cover the IMPLICIT scheme.

This will be superceded by a more bug-free soil temperature scheme
in the next major release of the model.

Fixed incorrect assignment of input forcing variables that are moisture fluxes (all forms of precipitation and channel inflow) when ALMA_INPUT is TRUE.

Files Affected:

initialize_atmos.c

Description:

When ALMA_INPUT was TRUE, VIC was not rescaling moisture fluxes such
as precipitation to an hourly time step correctly in initialize_atmos.
This led to incorrect assignment of these fluxes to the atmos array.
This has been fixed.

Fixed selection of starting point in forcing file when starting in the middle of a day

Files Affected:

make_dmy.c

Description:

For the case of STARTHOUR not equal to 0, VIC was not finding the
correct starting record in the forcing file, due to its missing a
check on the hour of the forcing record.  This has been fixed.

Fixed incorrect handling of case of a mix of cells with and without lakes.

Files Affected:

initialize_model_state.c
read_lakeparam.c

Description:

VIC was neither reading the lake parameter file correctly nor
initializing the lake data structures correctly for the case of a
mix of cells with and without lakes within a single lake parameter
file.  This has been fixed.

Fixed use of tmp_moist array without initialization.

Files Affected:

initialize_model_state.c

Description:

Fixed use of tmp_moist array without initialization.

Fixed use of uninitialized soil moisture values on first time step.

Files Affected:

initialize_model_state.c

Description:

The tmp_moist array, used in initialize_model_state() as an input to
compute_runoff_and_asat(), was initialized within an if statement that
caused it to be sent to compute_runoff_and_asat() without initialization
in some cases.  This has been fixed by moving the initialization of
tmp_moist outside the if statement.

Fixed errors in forcing disaggregation under certain input cases.

Files Affected:

initialize_atmos.c
mtclim_vic.c
mtclim_wrapper.c

Description:

Fixed bugs in the following cases:
1. User supplied daily incoming shortwave (not sub-daily)
2. User supplied daily specific or relative humidity without supplying
   average daily pressure or temperature, respectively (with which to
   convert these to daily vapor pressure).

Fixed bug in root zone calculation.

Files Affected:

calc_root_fraction.c

Description:

Fixed infinite loop that was occurring when the total  of root zone
depths exceeded the total soil depth and one of the root zone boundaries
coincided with a soil layer boundary.

Fixed error in passing SensibleHeat to func_atmos_energy_bal.

Files Affected:

calc_atmos_energy_bal.c

Description:

Replaced (*SensibleHeat) with SensibleHeat in argument lists
of root_brent, error_print_atmos_energy_bal and
solve_atmos_energy_bal.

Fixed use of uninitialized variable in cold nose fix for frozen soil

Files Affected:

frozen_soil.c

Description:

Fixed use of uninitialized variable in cold nose fix for
frozen soil.  Code was attempting to check all nodes for a
cold nose, but this check requires accessing the value of the
next node, which is undefined when we check the bottom node.
Now the code does not check the bottom node (which is unlikely
to experience a cold nose anyway).

Fixed bug in converting from ALMA_INPUT moisture flux units

Files Affected:

initialize_atmos.c

Description:

Fixed bug in converting from ALMA_INPUT moisture flux units
to traditional units (was multiplying by number of seconds in
model step when should have been multiplying by number of seconds
in forcing step).

Fixed incorrect reporting of canopy energy balance terms.

Files Affected:

calc_atmos_energy_bal.c
calc_water_energy_balance_errors.c
put_data.c
surface_fluxes.c
vicNl.h

Description:

VIC was not summing under- and over-story energy fluxes correctly for the
case of a forest canopy with snow.  This only affected the reporting of
energy balance terms in VIC's output; internal calculations were fine.

In addition, a bug (sign error in flux summation) in VIC's calculation of
the surface energy balance (for output only) was fixed.  This reduces the
vast majority of the energy balance errors reported during the course of
a typical energy balance simulation.

Fixed incorrect summing of rain and snow components of precipitation over grid
cell

Files Affected:

full_energy.c

Description:

The amounts of rainfall and snowfall over the lake (or inundated wetland)
were being omitted from the grid cell totals.  This has been fixed.

Vapor pressure incorrect if user supplies (QAIR or REL_HUMID) + PRESSURE as
input forcings instead of vapor pressure.

Files Affected:

initialize_atmos.c

Description:

For the cases of the combination of (QAIR or REL_HUMID) plus PRESSURE
supplied as input forcings instead of VP, the logic distinguishing
between daily and sub-daily supplied PRESSURE was flawed, resulting
in incorrect values in both cases.  This has been fixed.

Incorrect handling of user-supplied tskc (cloud fraction) for LW_CLOUD==LW_CLOUD_DEARDORFF

Files Affected:

calc_longwave.c
mtclim_vic.c

Description:

Previous versions of VIC (before 4.1.2) used a full-sky longwave
formulation taken from two formulas in the Bras hydrology text.  For
the new Deardorff full-sky longwave formulation, the dependence on
cloud fraction is different from the old Bras formulation.   In 
4.1.2 (and 4.1.2.a-b), the new Deardorff formulation did not account
for the possibility of user-supplied cloud fraction; if the user
supplied cloud fraction as an input forcing, the resulting longwave
was wrong.  This has been fixed.

Changed default settings of MTCLIM_SWE_CORR and LW_TYPE to reflect best
general settings

Files Affected:

initialize_global.c
global.param.sample

Description:

In light of the findings of Bohn et al. (2012), we have changed the
default setting of MTCLIM_SWE_CORR to FALSE and of LW_TYPE to
LW_PRATA.  These settings give forcing estimates that are less biased
in general.

Vapor pressure set to 0 if user supplies (QAIR or REL_HUMID) + PRESSURE as
input forcings instead of vapor pressure.

Files Affected:

initialize_atmos.c

Description:

For the cases of the combination of (QAIR or REL_HUMID) plus PRESSURE
supplied as input forcings instead of VP, VIC was supposed to compute
VP from (QAIR or REL_HUMID) and PRESSURE, then transfer the computed
VP to the atmos data structure.  This transfer was being skipped, and
vapor pressure was consequently set to 0 during the simulation.  This
has been fixed.

Computed longwave sometimes is extremely large at high latitudes.

Files Affected:

mtclim_vic.c

Description:

Previously (VIC 4.1.2, 4.1.2.a, and 4.1.2.b only), when SHORTWAVE and
VP were supplied to VIC as input forcings (and LONGWAVE was NOT
supplied as a forcing), the incoming longwave radiation computed by
VIC would in rare cases become extremely large.  This happens only at
high latitudes in winter when the theoretical clear-sky potential
solar radiation is very small.  If the supplied VP was large enough,
it could cause the internal variable t_tmax (clear-sky transmittance)
to go negative.  This in turn would cause the internal variable
t_fmax (cloud transmittance) to go negative as well.  This, finally,
would cause computed LONGWAVE values to become extremely large, if
the LW_CLOUD method was set to DEARDORFF.  This has been fixed.

VIC was unnecessarily requiring WIND to be supplied as an input forcing.

Files Affected:

initialize_atmos.c
vicNl_def.h

Description:

VIC was requiring WIND (or the zonal and meridional components of
wind, WIND_E and WIND_N) to be supplied as an input forcing.  Now VIC
allows WIND to be omitted.  If WIND is not supplied as an input
forcing, VIC will supply a default wind speed, defined in vicNl_def.h
as DEFAULT_WIND_SPEED and currently set to 3.0 m/s.

Cloud fraction tskc was not accounting for the case in which observed incoming
shortwave is supplied as a forcing.

Files Affected:

mtclim_vic.c

Description:

In the absence of observations, VIC's estimate of cloud fraction, tskc,
is a function of some intermediate quantities that are computed within
the MTCLIM algorithm (in mtclim_vic.c).  These intermediate terms
can be computed from either observed daily shortwave radiation (if
available) or simulated daily shortwave radiation.  The computation
of tskc was previously taking place in a part of the code where
only the simulated daily shortwave radiation was available.  Thus,
tskc would not reflect the actual amount of incident shortwave, even
if observed incident shortwave was supplied as a forcing.

This has been fixed.  The tskc computation has been moved to another
location in the code where the observed daily shortwave can be
accessed (if supplied by the user as a forcing).

Incorrect timing of disaggregated radiation and air temperature when daily
forcings are supplied and off_gmt is 0.

Files Affected:

initialize_atmos.c

Description:

VIC was double-shifting the timeseries of subdaily radiation and
temperature in cases in which VIC was *not* given sub-daily incoming
shortwave as an input forcing *and* soil parameter "off_gmt" was not
set to the local time zone offset (i.e. not set to longitude*24/360).
This caused incorrect timing of the diurnal cycle of radiation and
air temperature.

This has been fixed.

Disaggregated radiation is constant throughout the day when daily incoming
shortwave radiation is supplied as an input forcing.

Files Affected:

initialize_atmos.c
mtclim_constants_vic.h
mtclim_vic.c
mtclim_wrapper.c

Description:

When VIC was supplied with *daily* incoming shortwave as an input
forcing variable, VIC would fail to disaggregate this correctly to
sub-daily time steps; it would simply repeat the daily average for
every sub-daily time step.  This has been fixed.  Now VIC will
compute a diurnal cycle whose daily average matches the supplied daily
average.

Miscellaneous:

Better out-of-box behavior for soil temperature scheme

Files Affected:

get_global_param.c
global.param.sample
initialize_global.c
initialize_model_state.c

Description:

Added constraints to help ensure efficient, physically reasonable
simulation of the soil temperature profile:

1. Set default values of IMPLICIT and EXP_TRANS to TRUE.

2. Made "cold" (no-spinup) initial soil temperatures more consistent
with air temperature and bottom boundary temperature.

3. Added validation of option.Nnodes for EXP_TRANS=TRUE to guarantee
that, for the given soil temperature bottom boundary depth "dp" (also
known as the damping depth), there are at least 3 nodes within the top
50 cm of the soil column.  This is to constrain errors to a reasonable
size.  To satisfy this condition, the following relationship must hold:
    Nnodes >= 5*ln(dp+1)+1

Some examples:
dp(m)   minimum Nnodes
  4        9
  7       12
 10       14
 25       18
 50       21

VIC will exit with an error message to this effect if Nnodes is too
small for the given value of dp.

Cleanup of compile-time options

Files Affected:

arno_evap.c
calc_atmos_energy_bal.c
calc_forcing_stats.c (removed)
calc_longwave.c
calc_surf_energy_bal.c
canopy_evap.c
check_files.c
close_files.c
display_current_settings.c
frozen_soil.c
full_energy.c
func_canopy_energy_bal.c
func_surf_energy_bal.c
get_global_param.c
ice_melt.c
initialize_atmos.c
initialize_global.c
initialize_lake.c
initialize_model_state.c
initialize_new_storm.c
initialize_soil.c
LAKE.h
lakes.eb.c
Makefile
output_list_utils.c
prepare_full_energy.c
put_data.c
read_lakeparam.c
read_initial_model_state.c
read_soilparam_arc.c
read_soilparam.c
read_vegparam.c
redistribute_during_storm.c
runoff.c
snow_intercept.c
soil_conduction.c
soil_thermal_eqn.c
SnowPackEnergyBalance.c
solve_snow.c
surface_fluxes.c
user_def.h (removed)
vicNl_def.h
vicNl.c
vicNl.h
write_data.c
write_forcing_file.c
write_header.c
write_layer.c
write_model_state.c

Description:

Cleanup of user_def.h, either by removing options/settings or moving
them to vicNl_def.h (becoming run-time options if appropriate).
user_def.h has been removed.

The following options were removed:

* NO_REWIND.  All parameter files must contain the same grid cells in
  the same order.
* QUICK_FS.
* EXCESS_ICE.
* OUTPUT_FORCE_STATS.
* LWAVE_COR.  If the user wishes to correct any of the forcing
  variables, the user can do this externally to VIC.

The following options were moved from compile-time to run-time (in the
options_struct in vicNl_def.h):

* LOW_RES_MOIST (renamed to LOG_MATRIC)
* OUTPUT_FORCE
* CLOSE_ENERGY
* SPATIAL_SNOW
* SPATIAL_FROST

The following terms were moved to vicNl_def.h without modification:

* VERBOSE (still a compile-time option)
* Max array dimensions such as MAX_VEG, MAX_LAYERS, etc.
* Constants such as MAXIT_FE and LAI_WATER_FACTOR

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 10 years ago

VIC - Release of VIC.4.2.a

Description of changes between VIC 4.2 and VIC 4.2.a

Bug Fixes:

Fixed unitialized bare soil albedo.

Files Affected:

full_energy.c

Description:

Previously, bare_albedo was unset for the bare soil case (`iveg!=Nveg`).
This fix sets the bare_albedo to the global variable value of
`BARE_SOIL_ALBEDO`.

Cleanup of frozen soil option constraints.

Files Affected:

calc_surf_energy_bal.c
get_global_param.c

Description:

Removed hardcoded, behind the scenes checks for the `EXP_TRANS` and
`NO_FLUX` global parameter values for case of `QUICK_SOLVE=TRUE` in
`calc_surf_energy_bal`.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 10 years ago

VIC - Release of VIC.4.1.2.m

* Description of changes from VIC 4.1.2.l to VIC 4.1.2.m *

Bug Fixes:

Fixed negative liquid soil moisture for bare soil conditions

Files Affected:

runoff.c

Description:

Previously, runoff() only checked whether total (liquid+ice) soil
moisture was > residual moisture, but not whether liquid soil moisture
was positive. In some cases, in the bare soil tile, liquid soil moisture
could occasionally go negative. This has been fixed by adding a check on
liquid soil moisture to runoff().

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman almost 11 years ago

VIC - Release of VIC.4.1.2.l

* Description of changes from VIC 4.1.2.k to VIC 4.1.2.l *

Bug Fixes:

Fixed memory leak in vicNl()

Files Affected:

vicNl.c

Description:

Several soil_con arrays, allocated in read_soilparam(), were not being
freed in vicNl() due to the "free" statements being inside the wrong
OUTPUT_FORCE "if" block. This has been fixed.

Uninitialized variables in write_forcing_file().

Files Affected:

write_forcing_file.c

Description:

Placeholder variables (dummy_*) in write_forcing_file() were not
initialized, resulting in warnings during compilation. These are now
initialized. This should not affect any model results, since these
variables were never used.

Compilation errors when EXCESS_ICE = TRUE

Files Affected:

full_energy.c
initialize_model_state.c
lakes.eb.c

Description:

Miscellaneous typos in the EXCESS_ICE code prevented compilation
when EXCESS_ICE = TRUE in user_def.h. These have been fixed.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman about 11 years ago

VIC - Release of VIC.4.1.2.k

* Description of changes from VIC 4.1.2.j to VIC 4.1.2.k *

Bug Fixes:

Fix for crash when FROZEN_SOIL, EXP_TRANS and IMPLICIT all == TRUE

Files Affected:

frozen_soil.c
func_surf_energy_bal.c
vicNl.h

Description:

Extended the "cold nose" hack to the "warm nose" condition, and also
extended to cover the IMPLICIT scheme.

This will be superceded by a more bug-free soil temperature scheme
in the next major release of the model.

Better out-of-box behavior for soil temperature scheme

Files Affected:

get_global_param.c
global.param.sample
initialize_global.c
initialize_model_state.c

Description:

Added constraints to help ensure efficient, physically reasonable
simulation of the soil temperature profile:

Set default values of IMPLICIT and EXP_TRANS to TRUE.
Made "cold" (no-spinup) initial soil temperatures more consistent
with air temperature and bottom boundary temperature.
Added validation of option.Nnodes for EXP_TRANS=TRUE to guarantee
that, for the given soil temperature bottom boundary depth "dp" (also
known as the damping depth), there are at least 3 nodes within the top
50 cm of the soil column. This is to constrain errors to a reasonable
size. To satisfy this condition, the following relationship must hold:
Nnodes >= 5*ln(dp+1)+1

Some examples:
dp(m) minimum Nnodes
4 9
7 12
10 14
25 18
50 21

VIC will exit with an error message to this effect if Nnodes is too
small for the given value of dp.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman about 11 years ago

VIC - Release of VIC.4.1.2.j

* Description of changes from VIC 4.1.2.i to VIC 4.1.2.j *

Bug Fixes:

Fixed incorrect assignment of input forcing variables that are moisture fluxes (all forms of precipitation and channel inflow) when ALMA_INPUT is TRUE.

Files Affected:

initialize_atmos.c

Description:

When ALMA_INPUT was TRUE, VIC was not rescaling moisture fluxes such
as precipitation to an hourly time step correctly in initialize_atmos.
This led to incorrect assignment of these fluxes to the atmos array.
This has been fixed.

Fixed selection of starting point in forcing file when starting in the middle of a day

Files Affected:

make_dmy.c

Description:

For the case of STARTHOUR not equal to 0, VIC was not finding the
correct starting record in the forcing file, due to its missing a
check on the hour of the forcing record.  This has been fixed.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman about 11 years ago

VIC - Release of VIC.4.1.2.i

* Description of changes from VIC 4.1.2.h to VIC 4.1.2.i *

Bug Fixes:

Fixed incorrect handling of case of a mix of cells with and without lakes.

Files Affected:

initialize_model_state.c
read_lakeparam.c

Description:

VIC was neither reading the lake parameter file correctly nor
initializing the lake data structures correctly for the case of a
mix of cells with and without lakes within a single lake parameter
file. This has been fixed.

Fixed use of tmp_moist array without initialization.

Files Affected:

initialize_model_state.c

Description:

Fixed use of tmp_moist array without initialization.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.2.h

* Description of changes from VIC 4.1.2.g to VIC 4.1.2.h *

Bug Fixes:

Fixed use of uninitialized soil moisture values on first time step.

Files Affected:

initialize_model_state.c

Description:

The tmp_moist array, used in initialize_model_state() as an input to
compute_runoff_and_asat(), was initialized within an if statement that
caused it to be sent to compute_runoff_and_asat() without initialization
in some cases.  This has been fixed by moving the initialization of
tmp_moist outside the if statement.

Fixed errors in forcing disaggregation under certain input cases.

Files Affected:

initialize_atmos.c
mtclim_vic.c
mtclim_wrapper.c

Description:

Fixed bugs in the following cases:
1. User supplied daily incoming shortwave (not sub-daily)
2. User supplied daily specific or relative humidity without supplying
   average daily pressure or temperature, respectively (with which to
   convert these to daily vapor pressure).

Fixed bug in root zone calculation.

Files Affected:

calc_root_fraction.c

Description:

Fixed infinite loop that was occurring when the total  of root zone
depths exceeded the total soil depth and one of the root zone boundaries
coincided with a soil layer boundary.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.2.g

* Description of changes from VIC 4.1.2.f to VIC 4.1.2.g *

Bug Fixes:

Fixed error in passing SensibleHeat to func_atmos_energy_bal.

Files Affected:

calc_atmos_energy_bal.c

Description:

Replaced (*SensibleHeat) with SensibleHeat in argument lists
of root_brent, error_print_atmos_energy_bal and
solve_atmos_energy_bal.

* Description of changes from VIC 4.1.2.e to VIC 4.1.2.f *

Bug Fixes:

Fixed use of uninitialized variable in cold nose fix for frozen soil

Files Affected:

frozen_soil.c

Description:

Fixed use of uninitialized variable in cold nose fix for
frozen soil.  Code was attempting to check all nodes for a
cold nose, but this check requires accessing the value of the
next node, which is undefined when we check the bottom node.
Now the code does not check the bottom node (which is unlikely
to experience a cold nose anyway).

Fixed bug in converting from ALMA_INPUT moisture flux units

Files Affected:

initialize_atmos.c

Description:

Fixed bug in converting from ALMA_INPUT moisture flux units
to traditional units (was multiplying by number of seconds in
model step when should have been multiplying by number of seconds
in forcing step).

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.2.d

* Description of changes from VIC 4.1.2.c to VIC 4.1.2.d *

Bug Fixes:

Fixed incorrect summing of rain and snow components of precipitation over grid
cell

Files Affected:

full_energy.c

Description:

The amounts of rainfall and snowfall over the lake (or inundated wetland)
were being omitted from the grid cell totals.  This has been fixed.

Vapor pressure incorrect if user supplies (QAIR or REL_HUMID) + PRESSURE as
input forcings instead of vapor pressure.

Files Affected:

initialize_atmos.c

Description:

For the cases of the combination of (QAIR or REL_HUMID) plus PRESSURE
supplied as input forcings instead of VP, the logic distinguishing
between daily and sub-daily supplied PRESSURE was flawed, resulting
in incorrect values in both cases.  This has been fixed.

* Description of changes from VIC 4.1.2.b to VIC 4.1.2.c *

Bug Fixes:

Incorrect handling of user-supplied tskc (cloud fraction) for LW_CLOUD==LW_CLOUD_DEARDORFF

Files Affected:

calc_longwave.c
mtclim_vic.c

Description:

Previous versions of VIC (before 4.1.2) used a full-sky longwave
formulation taken from two formulas in the Bras hydrology text.  For
the new Deardorff full-sky longwave formulation, the dependence on
cloud fraction is different from the old Bras formulation.   In 
4.1.2 (and 4.1.2.a-b), the new Deardorff formulation did not account
for the possibility of user-supplied cloud fraction; if the user
supplied cloud fraction as an input forcing, the resulting longwave
was wrong.  This has been fixed.

Changed default settings of MTCLIM_SWE_CORR and LW_TYPE to reflect best
general settings

Files Affected:

initialize_global.c
global.param.sample

Description:

In light of the findings of Bohn et al. (2012), we have changed the
default setting of MTCLIM_SWE_CORR to FALSE and of LW_TYPE to
LW_PRATA.  These settings give forcing estimates that are less biased
in general.

Vapor pressure set to 0 if user supplies (QAIR or REL_HUMID) + PRESSURE as
input forcings instead of vapor pressure.

Files Affected:

initialize_atmos.c

Description:

For the cases of the combination of (QAIR or REL_HUMID) plus PRESSURE
supplied as input forcings instead of VP, VIC was supposed to compute
VP from (QAIR or REL_HUMID) and PRESSURE, then transfer the computed
VP to the atmos data structure.  This transfer was being skipped, and
vapor pressure was consequently set to 0 during the simulation.  This
has been fixed.

Computed longwave sometimes is extremely large at high latitudes.

Files Affected:

mtclim_vic.c

Description:

Previously (VIC 4.1.2, 4.1.2.a, and 4.1.2.b only), when SHORTWAVE and
VP were supplied to VIC as input forcings (and LONGWAVE was NOT
supplied as a forcing), the incoming longwave radiation computed by
VIC would in rare cases become extremely large.  This happens only at
high latitudes in winter when the theoretical clear-sky potential
solar radiation is very small.  If the supplied VP was large enough,
it could cause the internal variable t_tmax (clear-sky transmittance)
to go negative.  This in turn would cause the internal variable
t_fmax (cloud transmittance) to go negative as well.  This, finally,
would cause computed LONGWAVE values to become extremely large, if
the LW_CLOUD method was set to DEARDORFF.  This has been fixed.

* Description of changes from VIC 4.1.2.a to VIC 4.1.2.b *

Bug Fixes:

VIC was unnecessarily requiring WIND to be supplied as an input forcing.

Files Affected:

initialize_atmos.c
vicNl_def.h

Description:

VIC was requiring WIND (or the zonal and meridional components of
wind, WIND_E and WIND_N) to be supplied as an input forcing.  Now VIC
allows WIND to be omitted.  If WIND is not supplied as an input
forcing, VIC will supply a default wind speed, defined in vicNl_def.h
as DEFAULT_WIND_SPEED and currently set to 3.0 m/s.

Cloud fraction tskc was not accounting for the case in which observed incoming
shortwave is supplied as a forcing.

Files Affected:

mtclim_vic.c

Description:

In the absence of observations, VIC's estimate of cloud fraction, tskc,
is a function of some intermediate quantities that are computed within
the MTCLIM algorithm (in mtclim_vic.c).  These intermediate terms
can be computed from either observed daily shortwave radiation (if
available) or simulated daily shortwave radiation.  The computation
of tskc was previously taking place in a part of the code where
only the simulated daily shortwave radiation was available.  Thus,
tskc would not reflect the actual amount of incident shortwave, even
if observed incident shortwave was supplied as a forcing.

This has been fixed.  The tskc computation has been moved to another
location in the code where the observed daily shortwave can be
accessed (if supplied by the user as a forcing).

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.2

* Description of changes from VIC 4.1.2 to VIC 4.1.2.a *

Bug Fixes:

Incorrect timing of disaggregated radiation and air temperature when daily
forcings are supplied and off_gmt is 0.

Files Affected:

initialize_atmos.c

Description:

VIC was double-shifting the timeseries of subdaily radiation and
temperature in cases in which VIC was *not* given sub-daily incoming
shortwave as an input forcing *and* soil parameter "off_gmt" was not
set to the local time zone offset (i.e. not set to longitude*24/360).
This caused incorrect timing of the diurnal cycle of radiation and
air temperature.

This has been fixed.

Disaggregated radiation is constant throughout the day when daily incoming
shortwave radiation is supplied as an input forcing.

Files Affected:

initialize_atmos.c
mtclim_constants_vic.h
mtclim_vic.c
mtclim_wrapper.c

Description:

When VIC was supplied with *daily* incoming shortwave as an input
forcing variable, VIC would fail to disaggregate this correctly to
sub-daily time steps; it would simply repeat the daily average for
every sub-daily time step.  This has been fixed.  Now VIC will
compute a diurnal cycle whose daily average matches the supplied daily
average.

* Description of changes from VIC 4.1.1 to VIC 4.1.2 *

New Features:

Cleaned up the sample global parameter file

Files Affected:

get_global_param.c
global.param.sample
initialize_global.c

Description:

The large number of options available in VIC 4.1.2 has begun
to clutter the global parameter file, making it difficult for
users to determine which options need to be set.

Now the sample global parameter file groups the various options
into several categories, making a clear distinction between
those options that need to be changed by the user for each
simulation, and those that rarely need to be changed.  Those
options that rarely need to be changed are commented out, and VIC
now sets those options to the most commonly-used default values.

Removal of obsolete model options

    Files Affected:

    arno_evap.c
    canopy_evap.c
    close_files.c
    cmd_proc.c
    compute_zwt.c
    display_current_settings.c
    dist_prec.c
    frozen_soil.c
    full_energy.c
    func_canopy_energy_bal.c
    func_surf_energy_bal.c
    get_global_param.c
    global.h
    global.param.sample
    initialize_global.c
    initialize_lake.c
    initialize_model_state.c
    initialize_snow.c
    Makefile
    open_debug.c (removed)
    put_data.c
    read_lakeparam.c
    read_soilparam_arc.c
    read_soilparam.c
    read_veglib.c
    read_vegparam.c
    runoff.c
    store_moisture_for_debug.c (removed)
    surface_fluxes.c
    user_def.h
    vicerror.c
    vicNl.c
    vicNl_def.h
    vicNl.h
    write_atmosdata.c (removed)
    write_data.c
    write_debug.c (removed)

    Description:

We have removed some of the available model simulation options, due
to their being unrealistic or rarely used.  These include:

  GF_FULL value of GRND_FLUX_TYPE option.  This setting double-counted
    the effect of canopy attenuation of radiation.
  AR_COMBO value of AERO_RESIST_CANSNOW option.  This setting double-
    counted the effects of canopy snow on aerodynamic resistance.
  LINK_DEBUG option.  This user_def.h option would print out values of
    various water balance terms for debugging purposes, but was rarely
    used and difficult to maintain.

Overhaul of meteorological forcing processing

    Files Affected:

    alloc_atmos.c
    CalcBlowingSnow.c
calc_air_temperature.c
calc_longwave.c
display_current_settings.c
    get_force_type.c
    get_global_param.c
    global.param.sample
    initialize_atmos.c
    initialize_global.c
    Makefile
    mtclim_constants_vic.h (was mtclim42_vic.h)
    mtclim_parameters_vic.h (new file)
    mtclim_wrapper.c (was mtclim42_wrapper.c)
    mtclim_vic.c (was mtclim42_vic.c)
    output_list_utils.c
    put_data.c
    read_atmos_data.c
    read_soilparam.c
    vicNl_def.h
    vicNl.h
    write_forcing_file.c

    Description:

Numerous bug fixes and improvements to VIC's meteorological forcing
processing.

Bug fixes:

Two main bugs fixed, both primarily affecting high-latitude grid
cells:

1. On days having only 1 hour of darkness, the diurnal cycle
   of temperature was incorrect, skipping that day's minimum
   temperature and smoothly transitioning to the next day's
   maximum.

2. The seasonal evolution of the diurnal cycle of solar radiation
   was always 366 days long, so that the number of daylight hours got
   increasingly out of phase with the time of year (by one day per
   non-leap year) as the simulation progressed.  After 20-30 years,
   the diurnal cycle was substantially different from what it should
   be.  Above 60 N, the number of days having no sunlight was
   substantially longer than it should be.

Also fixed inconsistencies in the timing of meteorological variables
when sub-daily met variables were supplied by the user.  Now, we have
adopted the following convention:
      daily supplied forcings are assumed to start/end at midnight in
    local time; for these forcings, off_gmt in the soil parameter file
    is ignored
  sub-daily supplied forcings are assumed to occur relative to the time
    zone indicated by off_gmt in the soil parameter file

New features:

    Updated VIC's internal version of the MTCLIM forcing disaggregation
    functions from version 4.2 (Thornton and Running, 1999) to include
elements of version 4.3 (Thornton et al 2000).  

    This update includes 6 main changes to the forcing estimation scheme:

    1. Optional correction of downward shortwave for the effect of snow.
   In the presence of snow, incoming shortwave radiation has been
   observed to be higher than MTCLIM 4.2's estimates, due to
   scattering of light from the snow back into the atmosphere (and
   ultimately back to the ground again).  This correction is optional
   and is controlled by the new global parameter option MTCLIM_SWE_CORR.
   If this is set to TRUE, the correction is performed when snow is
   present on the ground (estimated by a simple degree-day model in
   the forcing pre-processor).  If FALSE, the correction is not
   performed (and shortwave is estimated as in previous versions of
   VIC).  The default value of MTCLIM_SWE_CORR is TRUE.

    2. Optional changes in the iteration between shortwave and VP
   estimates.  The algorithm for estimating shortwave requires
   observed VP as an input; the algorithm for estimating VP requires
   observed shortwave as an input.  Therefore, when neither quantity is
   observed, MTCLIM 4.2 (and previous versions of VIC) used the
   Tdew = Tmin approximation to supply the shortwave estimate with
   an estimate of daily vapor pressure.  Then the resulting shortwave
   estimate was used to compute a more accurate estimate of Tdew and
   vapor pressure.  MTCLIM 4.3 imposes an annual aridity criterion for
   performing this final step; for humid environments (annual PET <
   2.5 * annual precip) the scheme simply assumes daily Tdew = daily
   Tmin.  We have found that this behavior introduces a strong
   positive bias into vapor pressure, and have chosen to make it
   optional.  Therefore, we have introduced the new global
   parameter option VP_ITER to control the shortwave-vp iteration.  It
   can take on the following values:

     VP_ITER_NEVER = never perform the final update of Tdew and VP
     VP_ITER_ALWAYS = always perform the final update of Tdew and VP
     VP_ITER_ANNUAL = use the annual aridity criterion (annual PET <
                          2.5 * annual precip) do decide whether to perform
                      the final update
     VP_ITER_CONVERGE = continue iterating between shortwave and vp
                        until the two values stabilize (this tends
                        to give almost identical results to
                        VP_ITER_ALWAYS)

   The default value of VP_ITER is VP_ITER_ALWAYS.

3. To make the sub-daily values of VP more accurate, we have introduced
   another global parameter option: VP_INTERP.  If set to TRUE, VIC will
   assign the daily VP value computed by the MTCLIM functions to the
   time of sunrise on that day, and interpolate linearly between sunrise
   vapor pressure values of adjacent days.  If set to FALSE, VIC will
   hold vapor pressure constant over the entire day as in previous
   versions.  The default value of VP_INTERP is TRUE.

4. Alternative clear-sky longwave algorithms.  We have introduced a
   new global parameter option: LW_TYPE.  This option determines which
   algorithm is used to compute clear-sky longwave radiation.
   Choices are:

     LW_TVA = algorithm of Tennessee Valley Authority (TVA, 1972)
    (This is what all previous versions of VIC have used.  Our tests
    indicate that this algorithm is still the best when observed
    cloud fractions are unavailable and are estimated by MTCLIM,
    which is the current situation for VIC.)
     LW_ANDERSON = algorithm of Anderson (1964)
     LW_BRUTSAERT = algorithm of Brutseart (1975)
     LW_SATTERLUND = algorithm of Satterlund (1979)
     LW_IDSO = algorithm of Idso (1981)
     LW_PRATA = algorithm of Prata (1996) (Our tests indicate that
    this algorithm is best when observed cloud fractions are
    supplied as a forcing.)

   Default is set to LW_TVA.

5. Alternative cloud longwave emission algorithms.  We have introduced
   a new global parameter option: LW_CLOUD.  This option
   determines which algorithm is used to simulate the effect of
   cloudiness on incoming longwave radiation.  Choices are:

     LW_CLOUD_BRAS = algorithm composed of equations 2.29 and 2.43
    from the Bras textbook (Bras, R. L., "Hydrology, an
    introduction to hydrologic science", Addison-Wesley, Reading,
    Massachusetts, 1990).  This was the algorithm used in all
    previous releases of VIC. (Our tests indicate that this
    algorithm introduces substantial temperature-dependent biases
    in longwave estimates outside of the temperate zone)
     LW_CLOUD_DEARDORFF = algorithm used in Deardorff (1978) in which
    cloud_fraction is assumed equal to
        (1 - actual_shortwave/theoretical_clear_sky_shortwave)
    and total sky emissivity is represented as the weighted average:
        cloud_fraction * cloud_emissivity
        + (1-cloud_fraction) * clear_sky_emissivity
    (Our tests indicate that this algorithm is superior)

   Default is set to LW_CLOUD_DEARDORFF.

6. Optional threshold for daily precipitation to cause dimming of
   incoming shortwave radiation.  Previously, any precipitation would
   cause estimated daily incoming shortwave radiation to dim by 25%.
   Because the smoothing/resampling methods used in creating gridded
   forcings can artificially "bleed" trace amounts of precipitation
   into neighboring grid cells, we introduced this threshold to
   counteract any resulting low biases in shortwave.  This is
   controlled by the global parameter file option SW_PREC_THRESH,
   which is the minimum amount of daily precipitation (in mm) that
   must be exceeded for shortwave to dim.  The default value is set to
   0.1 mm.

Added the ability to simulate organic soil.

Files Affected:

display_current_settings.c
frozen_soil.c
full_energy.c
func_surf_energy_bal.c
get_global_param.c
global.param.sample
initialize_global.c
initialize_model_state.c
lakes.eb.c
prepare_full_energy.c
read_soilparam_arc.c
read_soilparam.c
runoff.c
soil_conduction.c
vicNl_def.h
vicNl.h

Description:

Added logic to handle organic soil properties.  Added a new global
parameter file option, ORGANIC_FRACT. If ORGANIC_FRACT is TRUE, VIC
assumes that there are 3*Nlayer extra columns in the soil parameter
file, containing for each layer the organic fraction and bulk and soil
densities of the organic matter.  If ORGANIC_FRACT is FALSE or is
omitted, VIC assumes that the soil param file does not contain these
extra columns, and assumes that the soil contains 0 organic matter (as
in previous versions of VIC).

The organic fraction in the soil parameter file is the fraction of
soil (by volume) that is organic matter.  If this fraction is > 0,
then the quartz content and the original bulk and soil densities are
assumed to apply only to the mineral portion of the soil.  Internally,
VIC will compute the aggregate bulk and soil densities of the combined
mineral and organic portions of the soil and compute an aggregate soil
porosity.

VIC now uses equations taken from Farouki 1986 to compute the thermal
conductivity and heat capacity of the soil containing organic matter.
As organic fraction approaches 0, the soil properties approach those
of the mineral portion of the soil.

Extended computation of soil temperatures and ground heat flux to all modes of
operation.

Files Affected:

calc_soil_thermal_eqn.c
calc_surf_energy_bal.c
display_current_settings.c
frozen_soil.c
full_energy.c
func_surf_energy_bal.c
get_global_param.c
initialize_global.c
initialize_model_state.c
soil_conduction.c
surface_fluxes.c
vicNl_def.h
vicNl.h

Description:

Extended computation of soil temperatures and ground heat flux to all
modes of model operation.  Previously these quantities were only
computed when FROZEN_SOIL was TRUE.

Now soil temperatures, ice content, and ground heat flux are computed
as follows:

1. If FROZEN_SOIL is TRUE, there is no change to previous model
    behavior.  By default, soil temperature profile is computed via
    the finite element method of Cherkauer and Lettenmaier (1999),
    taking account of the phase change of ice.  (To use the Liang
    et al (1999) approximation, set QUICK_FLUX to TRUE; however
    this is not recommended because it doesn't handle the phase
    change of ice.)  If FULL_ENERGY is also TRUE, the surface
    temperature is computed via iteration over the surface energy
    balance; if FULL_ENERGY is FALSE, the surface temperature is
    set to air temperature.  Soil layer average temperatures and
    ice contents are computed and available for output.

2. If FROZEN_SOIL is FALSE, the ice phase change is not accounted for
    and soil layer ice contents are all set to 0.  Unlike previous
    versions, the soil layer temperatures and ice contents (=0)
    are now available for output.  The default method of computing
    soil temperature profile depends on the setting of the
    QUICK_FLUX option:
    a. QUICK_FLUX FALSE: use approximation of Liang et al (1999).
       This is the default method, if QUICK_FLUX is not specified
       in the global param file.
    b. QUICK_FLUX TRUE: use finite element method of Cherkauer et
       al. (1999).

Now that soil temperatures, ice contents, and ground heat fluxes are
always computed, the GRND_FLUX option has been removed.

Added computation of water table position.

Files Affected:

compute_zwt.c (new)
initialize_lake.c
initialize_soil.c
lakes.eb.c
Makefile
output_list_utils.c
put_data.c
read_soilparam.c
read_soilparam_arc.c
runoff.c
user_def.h
vicNl_def.h
vicNl.c
vicNl.h

Description:

Added computation of the water table position, "zwt".  Units are [cm]
and the position is negative below the soil surface.  To monitor
the water table position, we have added the following output variables:

  OUT_ZWT  - water table position [cm] computed by requiring that all
         layers below it are saturated, i.e. the water table will
         appear only in the lowest unsaturated layer.
  OUT_ZWT_LUMPED - water table position [cm] computed by combining all soil
         layers into a single layer and assuming the soil below
         is completely saturated.

The water table's position within a soil layer is computed from soil
water retention curves following Letts et al. (2000):

  w(z) = { ((zwt-z)/bubble)**(-1/b), z <  zwt-bubble
         { 1.0,                      z >= zwt-bubble
where
  z      = depth below surface [cm]
  w(z)   = relative moisture at depth z given by
           (moist(z) - resid_moist) / (max_moist - resid_moist)
  zwt    = depth of water table below surface [cm]
  bubble = bubbling pressure [cm]
  b      = 0.5*(expt-3)
Note that zwt-bubble = depth of the free water surface, i.e.
position below which soil is completely saturated.

This assumes water in unsaturated zone above water table
is always in equilibrium between gravitational and matric
tension (e.g., Frolking et al, 2002).

So, to find the soil moisture value in a layer corresponding
to a given water table depth zwt, we integrate w(z) over the
whole layer:

w_avg = average w over whole layer = (integral of w*dz) / layer depth

Then,
  layer moisture = w_avg * (max_moist - resid_moist) + resid_moist

Instead of the zwt defined above, we actually report free
water surface elevation zwt* = -(zwt-bubble).  I.e. zwt* < 0
below the soil surface, and marks the point of saturation
rather than pressure = 1 atm.

To store the (zwt,moisture) pairs in this relationship for each layer,
two new variables have been added to the soil_con_struct:
  zwtvmoist_zwt[MAX_LAYER][MAX_ZWTVMOIST]
  zwtvmoist_moist[MAX_LAYER][MAX_ZWTVMOIST]
These are computed in read_soilparam().  Then, in compute_zwt() VIC
interpolates between these points to estimate the water table depth
in each layer given the layer's current soil moisture.

Added channel inflow from upstream into the lake to the list of forcing
variables. Added lake water balance terms to input/output variables.

Files Affected:

alloc_atmos.c
full_energy.c
get_force_type.c
initialize_atmos.c
initialize_lake.c
initialize_model_state.c
LAKE.h
lakes.eb.c
output_list_utils.c
output.PILPS-2E.ALMA.template
output.TRADITIONAL.410.template
set_output_defaults.c
put_data.c
read_lakeparam.c
vicNl.c
vicNl_def.h
vicNl.h

Description:

Added forcing variable CHANNEL_IN to allow channel flow from
upstream grid cells to be an input into the lake.  This variable
is ignored if LAKES is set to FALSE or the lake/wetland tile has 0
area.  CHANNEL_IN must be in units of cubic meters [m3] per forcing
time step (or cubic meters per second [m3/s] if ALMA_INPUT is TRUE).

Several output variables have been added to aid in tracking the
lake water budget.  The complete set of lake water budget variables
is (in mm over grid cell area):

  OUT_LAKE_BF_IN    baseflow into lake from catchment
  OUT_LAKE_BF_OUT   baseflow out of lake
  OUT_LAKE_CHAN_IN  channel inflow into lake
  OUT_LAKE_CHAN_OUT channel outflow from lake
  OUT_LAKE_DSTOR    change in lake moisture storage (liquid plus
                ice cover)
  OUT_LAKE_DSWE     change in snowpack on top of lake ice
  OUT_LAKE_EVAP     (was OUT_EVAP_LAKE)
  OUT_PREC      (already existed)
  OUT_LAKE_RCHRG    recharge from lake to wetland
  OUT_LAKE_RO_IN    runoff into lake from catchment
  OUT_LAKE_VAPFLX   sublimation from lake snow
These same variables exist in units of volume (m**3):
  OUT_LAKE_BF_IN_V  baseflow into lake from catchment
  OUT_LAKE_BF_OUT_V baseflow out of lake
  OUT_LAKE_CHAN_IN_V    channel inflow into lake
  OUT_LAKE_CHAN_OUT_V   channel outflow from lake
  OUT_LAKE_DSTOR_V  change in lake moisture storage (liquid plus
                ice cover)
  OUT_LAKE_DSWE_V   change in snowpack on top of lake ice
  OUT_LAKE_EVAP_V   evap from lake
  OUT_LAKE_PREC_V   (note the "LAKE" in the name)
  OUT_LAKE_RCHRG_V  recharge from lake to wetland
  OUT_LAKE_RO_IN_V  runoff into lake from catchment
  OUT_LAKE_VAPFLX_V sublimation from lake snow

This change also involved changing how lake fluxes are represented
internally in VIC.  They are now represented as volumes (m3) per step.
This allows better handling of cases in which the lake shrinks to 0
area.

Added the output variable OUT_LAKE_AREA_FRAC, the lake surface area as a
fraction of the grid cell area.

Files Affected:

output_list_utils.c
put_data.c
vicNl_def.h

Description:

Added the output variable OUT_LAKE_AREA_FRAC, which tracks the lake
surface area as a fraction of the grid cell area.  This allows quick
comparison of VIC outputs with lake area observations (e.g. from
remote sensing).

Added validation of b_infilt

Files Affected:

read_soilparam.c

Description:

VIC now checks to make sure b_infilt > 0.  If the value is <= 0,
VIC exits with an error message.

Removed MIN_LIQ option.

Files Affected:

arno_evap.c
frozen_soil.c
get_global_param.c
global.param.sample
initialize_global.c
initialize_lake.c
initialize_model_state.c
initialize_soil.c
lakes.eb.c
runoff.c
soil_conduction.c
vicNl_def.h
vicNl.h

Description:

This option was intended to allow a dynamic (temperature-dependent)
lower bound on liquid soil moisture, based on the principle that, even
at very low temperatures, some moisture remains unfrozen.  However,
it ended up being unnecessary and its implementation introduced
undesirable complexity into the code.  In addition, it contained a bug
that allowed soil moisture to fall below residual moisture level.
Therefore this feature has been removed.

Bug Fixes:

Users can inadvertently choose an unstable soil temperature scheme

Files Affected:

get_global_param.c
initialize_global.c
initialize_model_state.c
newt_raph_func_fast.c

Description:

Previously VIC's default soil temperature scheme when
FROZEN_SOIL=TRUE was an explicit scheme whose stability
was not guaranteed.  VIC has had an optional implicit
scheme but this was not turned on unless the user chose
it.  This led to users inadvertently running VIC with
an unstable temperature scheme under certain combinations
of model time step and thermal node spacing.

This has been fixed.  Now the implicit scheme is turned
on by default (IMPLICIT=TRUE by default when FROZEN_SOIL
is TRUE).  The implicit scheme is stable for all combinations
of model time step and thermal node spacing.  Because this
can slow down VIC simulations in some cases, this option
can still be overridden by setting IMPLICIT to FALSE in the
global parameter file.  However, if the user does this,
VIC now checks to see if the simulation's model time step
and thermal node spacing are in the stable region; if not,
VIC aborts with an error message.

Clarified description and variable names in SPATIAL_SNOW option

Files Affected:

calc_snow_coverage.c
calc_surf_energy_bal.c
ice_melt.c
initialize_lake.c
initialize_snow.c
read_soilparam_arc.c
read_soilparam.c
solve_snow.c
vicNl_def.h
write_snow_data.c

Description:

The parameter for the snow pack depth distribution was previously
named "depth_full_snow_cover".  However, this parameter's function
was actually to represent the slope of the snow pack depth
distribution.  If we define "depth_thresh" to be the minimum snow
pack depth below which the coverage < 1, then
  depth_full_snow_cover MUST = 2*depth_thresh
This was very misleading and caused users some confusion.  Therefore
we have changed the name of the parameter to "max_snow_distrib_slope".
In addition, other associated variables in the snow_data structure
have been renamed accordingly (max_swq became max_snow_depth and
swq_slope became snow_distrib_slope).

Fixed incorrect diurnal radiation cycle at high latitudes

Files Affected:

See "Overhaul of meteorological forcing processing" under
new features

Description:

See "Overhaul of meteorological forcing processing" under
new features.  Two main bugs fixed, both primarily affecting
high-latitude grid cells:
  1. On days having only 1 hour of darkness, the diurnal cycle
     of temperature was incorrect, skipping that day's minimum
     temperature and smoothly transitioning to the next day's
     maximum.
  2. The seasonal evolution of the diurnal cycle of solar radiation
     was always 366 days long, so that the number of daylight hours got
     increasingly out of phase with the time of year (by one day per
     non-leap year) as the simulation progressed.  After 20-30 years,
     the diurnal cycle was substantially different from what it should
     be.  Above 60 N, the number of days having no sunlight was
     substantially longer than it should be.

Fixed incorrect computation of snow cover fraction over lake/wetland

Files Affected:

lakes.eb.c

Description:

Previously VIC didn't compute snow cover fraction correctly
over the lake/wetland tile.  This has been fixed.

Fixed VIC's inability to handle the case where some cells have lakes and
others don't.

Files Affected:

full_energy.c
read_initial_model_state.c
read_lakeparam.c
vicNl_def.h
write_model_state.c

Description:

VIC 4.1.1 and previous versions of 4.1.2 were unable to handle the
case in which some cells contain lakes and others don't.  If
options.LAKES was TRUE, all cells were required to have a valid
value of lake_idx to indicate which veg tile contained a lake,
even if no lakes existed in the cell.

This has been fixed.  Now, users can specify a cell that has no
lakes by setting lake_idx to -1 in the lake parameter file.  In
this case, VIC will ignore all other lake parameters for the cell
and set the cell's lake area permanently to 0.

Fixed bugs in declarations of frost_fract for SPATIAL_FROST TRUE

Files Affected:

lakes.eb.c
put_data.c
vicNl.h

Description:

Declarations for frost_fract were wrong or missing.  This has
been fixed.

Fixed various lake water balance errors.

Files Affected:

initialize_lake.c
initialize_model_state.c
initialize_soil.c
LAKE.h
lakes.eb.c
runoff.c
vicNl.h

Description:

Now calls to get_depth() are all consistent, using *liquid* water
volume instead of total volume (thus ldepth is always the liquid water
depth).  Lake ice area is not allowed to increase if ice area > liquid
area.  Ice cover is now treated like a "skin" on top of the liquid
(regardless of its thickness).  Ice is assumed to be completely buoyant,
i.e. none of the ice is below the water line.  If ice completely covers
the lake and the liquid part of the lake shrinks, the ice is assumed to
bend like a blanket, so that the outer edges now rest on land but the
center rests on top of the liquid.  The lake "area" is still considered
to be the ice cover in this case.  Baseflow out of the lake is only
allowed in the area of the lake containing liquid.  The edges of the ice
sheet are assumed to be vertical, i.e. the surface area of the top of the
ice sheet is equal to the surface area of the bottom of the ice sheet.
This fixes water balance errors arising from inconsistent estimates of
lake ice area.  Also fixed bugs in computation of lake->recharge.

Fixed incorrect snow albedo decay for southern hemisphere.

Files Affected:

LAKE.h
lakes.eb.c
solve_snow.c

Description:

Previously the computation of the USACE snow albedo decay would
only switch from accumulation to melt curves for dates between
March 1 and October 1.  These dates are only appropriate for the
northern hemisphere.  This has been fixed so that the reverse
condition must be met in the southern hemisphere.

Saturated area fraction incorrect for SPATIAL_FROST = TRUE.

Files Affected:

runoff.c

Description:

Previously the computation of cell.Asat occurred in the wrong
place in runoff.c so that it was only correct for SPATIAL_FROST
= FALSE.  This has been fixed.

State file handles are never closed.

Files Affected:

vicNl.c

Description:

Previously VIC was not closing the intial and final state files.
This has been fixed.

VIC aborts with soil temperature node moisture > max moisture.

Files Affected:

soil_conduction.c

Description:

Previously VIC would abort the simulation if soil temperature node
moisture ever became greater than the maximum allowable moisture.
This behavior has been replaced with a resetting of node moisture to
the maximum.  This is not intended to be a permanent fix; it simply
allows simulations to continue with minimal errors.  A more robust
fix is planned.

Initial lake depth < mindepth is reset to mindepth.

Files Affected:

read_lakeparam.c

Description:

The validation of initial lake depth was incorrectly resetting depth
to mindepth if initial depth < mindepth.  This has been fixed.

Soil moisture falls below residual moisture level in some cases.

Files Affected:

(see "Removed MIN_LIQ option" under "New Features")

Description:

The MIN_LIQ option contained a bug that allowed soil moisture to fall
below residual moisture level in some cases.  This feature has been
removed (see "Removed MIN_LIQ option" under "New Features").

Incorrect calculation of grnd_flux, deltaH, and fusion for EXP_TRANS=TRUE.

Files Affected:

arno_evap.c
calc_surf_energy_bal.c
frozen_soil.c
func_surf_energy_bal.c
get_global_param.c
initialize_model_state.c
modify_Ksat.c
solve_snow.c
surface_fluxes.c
vicNl.h

Description:

In 4.1.1, the calculation of grnd_flux, deltaH, and fusion involved
the assumption that soil thermal nodes 1 and 2 were at depths of
1*soil_con->depth[0] and 2*soil_con->depth[0], respectively.  This is
not true for exponential node spacing (EXP_TRANS=TRUE) or any other
node spacing scheme in general.  This has been fixed to allow
aribitrary node spacing.

The temperature profile given by the exponential node spacing is now
interpolated to find the temperatures at the same depths as for the
linear node spacing, i.e.  the boundary between the first and second
soil hydrologic layers.  This makes the computation of grnd_flux,
deltaH, and fusion consistent across all modes of operation (linear
and exponential node spacing AND the QUICK_FLUX approximation), since
now they all apply to the same control volume (first soil layer).

Simulation log messages appear out of order.

Files Affected:

display_current_settings.c
put_data.c

Description:

In 4.1.1, some messages sent to the screen would appear out of order
when saved to a log file.  This has been fixed by redirecting messages
from stdout to stderr.

Fixed typo in setting of fallback T value for the soil T profile.

Files Affected:

frozen_soil.c

Description:

In 4.1.1, the fallback temperature was erroneously set to "oldT",
which is the T value of the previous iteration, but not the value
from the beginning of the time step (except on the first iteration).
Now, "oldT" has been replaced by "T0".

Fixed typo in initialization of fallback counts for the soil T profile.

Files Affected:

frozen_soil.c

Description:

In 4.1.1, only the fallback counts for nodes 1 to Nnodes-2 were
initialized (to 0).  Now initialization is done for nodes 0 to
Nnodes-1.

Fixed various water balance errors in the lake model and added logic to handle
the case when lake area goes to 0.

Files Affected:

full_energy.c
lakes.eb.c
put_data.c
vicNl_def.h

Description:

In 4.1.1, the lake model would generate small water balance errors
when lake area would change, particularly in the presence of lake ice.
In addition, lake water balance terms would become NaN when lake
fraction went to 0.  These errors have been fixed.

Replaced "assert" statements with "if" statements.

Files Affected:

calc_atmos_energy_bal.c
calc_surf_energy_bal.c
ice_melt.c
snow_intercept.c
snow_melt.c
water_energy_balance.c
water_under_ice.c

Description:

Previous versions of these files contain "assert" statements, which
cause the model to abort if the assertions are not true.  These have
been replaced by "if" statements, so that the offending conditions can
be remedied and the simulation can continue.

Removed save_data structure initialization from initialize_model_state().

Files Affected:

initialize_model_state.c
put_data.c
vicNl.c
vicNl.h

Description:

For each time step, the initial values of the major moisture storage
terms are stored in the save_data structure, so that the difference
between final and initial states can be computed and written to
output.  In earlier versions, these variables needed to be initialized
in initialize_model_state() so that they contained valid values before
the first call to put_data().  This is no longer necessary, as the
model now initializes all output variables with an initial call to
put_data() before the simulation begins.  Thus, the initialization
has been removed from initialize_model_state().

Fixed typo in condition for reading Wdew values.

Files Affected:

read_initial_model_state.c

Description:

In 4.1.1, Wdew values were expected for even the bare soil veg tile,
despite the fact that these values are not saved for bare soil in the
function write_model_state().  This has been fixed; Wdew is no longer
expected for the bare soil tile.

Fixed bug in runoff computation when soil column is completely saturated.

Files Affected:

runoff.c

Description:

runoff() first computes total runoff for the timestep, and then computes
hourly vertical water movement through the soil column.  During the
hourly computations, if the entire soil column becomes saturated, some
downward-moving water may be "regurgitated" back up to the surface,
where it is added to the total runoff for the time step.

In 4.1.1, the hourly infiltration into the soil column is computed
using runoff[frost_area].  However, in the case of complete saturation,
the regurgitated excess water is added to runoff[frost_area] within
the hourly loop, so that the next hour's infiltration is computed
using a larger value of runoff[frost_area].  This leads to water
balance errors.  This has been fixed in 4.1.2.  Now, hourly
infiltration is only computed relative to the original estimate of
runoff[frost_area], before any regurgitated excess water is added to
it.

Fixed typo in writing of number of lake active nodes to ASCII-format state file.

Files Affected:

write_model_state.c

Description:

Fixed a typo in the writing of the number of lake active nodes to the
statefile, for ASCII format.  The error involved omitting a space that
would separate the active node number from the temperature of the
deepest soil thermal node, preventing the state file from being read
correctly in subsequent VIC runs.

Added TFALLBACK logic to soil thermal profile solution for case in which max
iterations are exceeded.

Files Affected:

frozen_soil.c

Description:

In 4.1.1, errors due to exceeding the maximum number of iterations in
the soil temperature profile computation in calc_soil_thermal_fluxes()
were not handled by the TFALLBACK option.  Logic to handle this case
has now been added.

Fixed bugs in initialization of various TFallback counts and flags.

Files Affected:

initialize_snow.c
frozen_soil.c

Description:

In 4.1.1, the number of Tfallbacks reported to the screen sometimes
came out negative; this has been fixed for fallbacks in snow surface
temperature and soil temperature profile.

Misc fixes to handling of aerodynamic resistance.

Files Affected:

func_surf_energy_bal.c
surface_fluxes.c

Description:

Replaced ra_under with Ra_used[0] in func_surf_energy_bal.c - this
should not change behavior; it simply cleans up the code a tad.

Added logic to surface_fluxes.c to handle cases when aero_cond and
aero_resist are 0 or very large.

Added hack to prevent runaway cold nose in soil temperature profile. This is
only enabled when options.TFALLBACK = TRUE.

Files Affected:

frozen_soil.c

Description:

In 4.1.1, the soil temprature computation could sometimes encounter a
runaway "cold nose", in which one node was colder than its neighbors
and continued to grow colder than its neighbors over time, due to
instabilities in the soil heat equation (in the presence of ice in the
soil).  A rigorous numerical solution to this problem has not yet been
implemented, but this hack causes the offending node to be reset to
the average of its neighbors' temperatures as soon as the runaway
behavior is detected.  We hope to implement a more rigorous solution
to this problem in future releases.

Simplified arguments lists of various functions.

Files Affected:

arno_evap.c
func_surf_energy_bal.c
initialize_atmos.c
snow_intercept.c
solve_snow.c
surface_fluxes.c
vicNl.c
vicNl.h

Description:

Replaced individual forcing and date/time variables in argument
lists of solve_snow() and snow_intercept() with the dmy and atmos
data structures.  Removed several unused variables from the arg list
of arno_evap().  Replaced individual soil_con variables in arg list
of initialize_atmos() with the soil_con structure.

Replaced GLOBAL_LAI option with 2 options: VEGPARAM_LAI and LAI_SRC.

Files Affected:

display_current_settings.c
get_global_param.c
global.param.sample
initialize_global.c
read_veglib.c
read_vegparam.c
vicNl_def.h

Description:

In previous versions, the GLOBAL_LAI option caused some confusion.
GLOBAL_LAI=TRUE indicated that LAI values should be read from the veg
parameter file (usually because they vary globally), and FALSE
indicated that LAI values should be read from the veg library (meaning
they were constant across the globe).  But the natural interpretation
of "GLOBAL_LAI=TRUE" is that LAI values are globally constant.  In
addition, the presence of LAI values in the veg param file was
dictated by the setting of GLOBAL_LAI.  If the user wanted to have VIC
read LAI values from the veg library, GLOBAL_LAI would need to be
FALSE, and the veg param file would need to have its LAI values
removed.  This linkage of veg param file format and where VIC was
looking for LAI values seemed unnecesary.

There are now 2 options controlling these 2 separate aspects of LAI.
VEGPARAM_LAI controls the *format* of the veg param file.  Independent
of this, LAI_SRC controls *where* VIC looks for LAI values.  This way,
1) the user can switch between the two sources of LAI values without
having to change the veg param file, and 2) the meanings of these
options are more clear than the old GLOBAL_LAI option.

The old GLOBAL_LAI setting has been maintained for backwards-
compatibility, i.e. if VIC encounters GLOBAL_LAI in the global
param file, it will set VEGPARAM_LAI and LAI_SRC appropriately.

Changed default number of soil layers from 2 to 3 (the most common
configuration).

Files Affected:

initialize_global.c

Description:

The default number of soil layers has been changed from 2 to 3 (the
most common configuration).  This will only affect users who have
omitted this setting from their global parameter files.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.0

* Description of changes from VIC 4.1.0 beta r4 to VIC 4.1.0 beta r5 *

New Features:

Updated lake model.

Files Affected:

full_energy.c
get_dist.c (new)
ice_melt.c
initialize_lake.c
lakes.eb.c
LAKE.h
Makefile
output_list_utils.c
put_data.c
read_initial_model_state.c
read_lakeparam.c
read_soilparam_arc.c
read_soilparam.c
vicNl_def.h
vicNl.c
vicNl.h
water_energy_balance.c
water_under_ice.c
wetland_energy.c
write_model_state.c

Description:

Merged Laura Bowling's latest lake model code into UW version.
Changes include:
  * Fixed lake snow physics to be consistent with land snow pack
  * Lake ice formation now takes into account availability of liquid water
  * Lake ice now explicitly tracked in water balance
  * Drainage now depends only on liquid water content, not total water+ice
  * Drainage now modeled as flow over broad-crested wier
  * New lake parameter file format - see read_lakeparam.c for details
  * Fixes for crashes in extreme cases; fixes for water balance errors
  * New output variable OUT_SOIL_TNODE_WL, the soil thermal node
    temperatures in the wetland tile
                                    LCB via TJB

New optional snow density computation.

Files Affected:

display_current_settings.c
get_global_param.c
initialize_global.c
snow.h
snow_utility.c
solve_snow.c
user_def.h
vicNl_def.h
vicNl.h

Description:

In addition to the previous algorithm (as a function of day of year,
based on a plot of seasonal variation of typical snow densities found
in Bras, figure 6.10, p 258), added a new algorithm that computes the
snow density based on swe and snow metamorphism.  The new algorithm is
taken from SNTHERM89, adjusted for an essentially single-layer model.
Introduced a new global parameter file option, SNOW_DENSITY, to choose
which of these density algorithms will be used.  If SNOW_DENSITY is set
to DENS_BRAS, the original algorithm is used.  If SNOW_DENSITY is set
to DENS_SNTHRM, the new algorithm is used.  The default value (i.e. if
SNOW_DENSITY is omitted) is DENS_BRAS.  Also moved snow-related
constants from user_def.h to snow.h, for consistency.           KMA via TJB

New optional snow albedo algorithm.

Files Affected:

display_current_settings.c
get_global_param.c
initialize_global.c
LAKE.h
lakes.eb.c
snow_utility.c
solve_snow.c
vicNl_def.h
vicNl.h

Description:

In addition to the previous algorithm (based on US Army Corps of
Engineers empirical snow albedo decay curves), added a new algorithm
based on Sun et al., 1999.  Introduced a new global parameter file
option, SNOW_ALBEDO, to choose which of these density algorithms will
be used.  If SNOW_ALBEDO is set to USACE, the original algorithm is
used.  If SNOW_ALBEDO is set to SUN1999, the new algorithm is used.
The default value (i.e. if SNOW_ALBEDO is omitted) is DENS_BRAS.    KAC via TJB

Bug Fixes:

Allow lakes to be empty or very shallow.

Files Affected:

initialize_lake.c
initialize_model_state.c
LAKE.h
lakes.eb.c
read_lakeparam.c
wetland_energy.c

Description:

Previously, lakes could not be initialized to be empty or with volume
below the minimum volume of 1 lake node.  This modification removes
that constraint.  In addition, the lake-specific get_* functions were
modified to return ErrorFlag values instead of aborting on error,
making them more consistent with the CONTINUEONERROR option.        KAC via TJB

Miscellaneous fixes to lake model

Files Affected:

lakes.eb.c
read_lakeparam.c
wetland_energy.c

Description:

Fixes for swe accounting errors and incorrect parsing of lake
parameter file.                             LCB via TJB

Lake snow and ice fixes

Files Affected:

LAKE.h
lakes.eb.c
vicNl_def.h

Description:

Modified to set lake ice fraction to 0 if new lake fraction is 0.
Previously lake ice was always adjusted by dividing old by new fractions,
which causes nans when the new fraction is 0.  Modified redistribution of
snow variables between wetland and lake ice.  Surface water is now stored
as a lake variable and used to reestablish surf_water at the start of a
new time step.                              KAC via TJB

Better validation of global parameter file options

Files Affected:
get_global_param.c
make_in_and_outfiles.c
parse_output_info.c
read_soilparam_arc.c
read_vegparam.c

Description:
Now, all options in the global parameter file involving input and
output files are checked to ensure that the filenames have been
specified.  In addition, SOIL_DIR and RESULT_DIR no longer require
a trailing "/"; a "/" is automatically appended when constructing
the soil parameter filename or results filename.  Also, makes sure
that N_OUTFILES matches number of output files actually defined in
the global param file.                          TJB

Incorrect soil ice fractions for the case when FROZEN_SOIL = TRUE and
options.SNOW_BAND > 1.

Files Affected:

full_energy.c
prepare_full_energy.c
surface_fluxes.c

Description:

Changed initial total and frozen moistures from scalars (moist and
ice0) to arrays (moist0 and ice0).  Previously, when
options.SNOW_BAND > 1, the values of moist and ice0 computed for
earlier bands were always overwritten by the values of moist and
ice0 computed for the final band (even if the final band had 0
area).                                  JS and KAC via TJB

Bad results when SNOW_STEP = 24 hours

Files Affected:

get_global_param.c
initialize_atmos.c

Description:

Fixed the criterion for deciding whether to store NET longwave or
INCOMING longwave in atmos[rec].longwave[NR].  Previously, VIC
stored NET lw if SNOW_STEP != global.dt, under the assumption that
this condition was equivalent to running in 24 h water balance mode.
However, this caused problems for users who unwittingly ran 24 h
water balance mode with SNOW_STEP = 24.  The new criterion is that
both FULL_ENERGY and FROZEN_SOIL must be FALSE.             TJB

Incorrect setting for NOFLUX option in calc_surf_energy_bal()

Files Affected:

calc_surf_energy_bal.c

Description:

Modified code to reset NOFLUX boundary to global option
value before computing final soil column temperatures.
Previously NOFLUX was set to FALSE for initial QUICK_SOLVE
estimates, but never reset to reflect actual bottom
boundary conditions for final pass through solver.          KAC

Removed -g from normal compiling options.

Files Affected:

Makefile

Description:

At some point, "-g" was added to the normal compiling options.
This has been removed.  To use the -g option, users should uncomment
the "debug" section of the makefile.                    TJB

Changed "vicInterp" to "vicDisagg".

Files Affected:

Makefile

Description:

Changed the name of the makefile option to compile vic with the
OUTPUT_FORCE option set to TRUE.  The term "disaggregate" is more
correct than the term "interpolate", so "vicDisagg" seems more
appropriate.  The usage of this option is as follows:

At command prompt, type
    make disagg

This will create the executable vicDisagg, which is simply vicNl
compiled with OUTPUT_FORCE set to TRUE in user_def.h.           TJB

Added end-of-file check to read_lakeparam.c

Files Affected:

read_lakeparam.c

Description:

Added check on !feof(lakeparam) to loop over lake param file, to
avoid infinite loop when current grid cell has no lakes and is not
mentioned in the lake param file.                   TJB

Compilation problems for QUICK_FS user_def.h option

Files Affected:

func_surf_energy_bal.c
get_global_param.c
initialize_model_state.c
read_lakeparam.c
water_energy_balance.c
wetland_energy.c

Description:

Previous updates for the EXCESS_ICE option had inadvertently introduced
bugs into the logic for the QUICK_FS option.  These included removal of
the logic that modifies calls to distribute_node_moisture_properties()
and estimate_layer_ice_content().                   TJB

OUT_SUB_BLOWING, OUT_SUB_SURFACE, and OUT_SUB_SNOW missing from default snow_*
output files.

Files Affected:

set_output_defaults.c

Description:

Added OUT_SUB_BLOWING, OUT_SUB_SURFACE, and OUT_SUB_SNOW to default
snow output file for case of options.BLOWING == TRUE.  This makes it
almost the same as previous versions of 4.1.0, (r3 and earlier) with
the exception that previous versions of 4.1.0 multiplied these terms
by 100 when saving to the snow file.                    TJB

Error in computation of initial water storage for DIST_PRCP = TRUE

Files Affected:

vicNl.c

Description:

Added dist_prcp fraction (mu) to the computation of initial water
storage terms.  Otherwise, when DIST_PRCP = TRUE, the water storage
terms for wet and dry fractions were added together with no weighting,
resulting in twice the storage as actually present.         TJB

Fixed various issues with uninitialized variables, un-freed arrays, NaN's, etc.

Files Affected:

dist_prec.c
put_data.c
read_vegparam.c
runoff.c
surface_fluxes.c
vicNl.h

Description:

put_data() was attempting to return an ErrorFlag but it was defined
as type int.  Therefore, changed the type of put_data() and changed
the call to put_data() in dist_prec.c.  read_vegparam() allocated
but never freed a temporary array vegarr[].  This was fixed.
In runoff(), top_moist could sometimes exceed top_max_moist due
to rounding errors, leading to NaN's in i_0 and A_0.  surface_fluxes()
was sending incorrectly-indexed displacement and roughness values to
CalcBlowingSnow().  These have all been fixed.      LCB via TJB

* Description of changes from VIC 4.1.0 beta r3 to VIC 4.1.0 beta r4 *

New Features:

Flexible output configuration & aggregation of output variables

    Files Affected:

    Makefile
alloc_atmos.c
calc_water_energy_balance_errors.c (new)
close_files.c
conv_force_vic2alma.c (removed)
conv_results_vic2alma.c (removed)
display_current_settings.c
dist_prec.c
full_energy.c
get_global_param.c
global.h
global.param.sample
IceEnergyBalance.c
initialize_atmos.c
initialize_global.c
initialize_model_state.c
make_in_and_outfiles.c
output.LDAS_OUTPUT.template (new)
output.OPTIMIZE.template (new)
output.OUTPUT_FORCE.ALMA.template (new)
output.OUTPUT_FORCE.template (new)
output.PILPS-2E.ALMA.template (new)
output.TRADITIONAL.410.template (new)
output.TRADITIONAL.template (new)
output_list_utils.c (new)
parse_output_info.c (new)
put_data.c
read_atmos_data.c
set_output_defaults.c (new)
SnowPackEnergyBalance.c
    solve_snow.c
surface_fluxes.c
user_def.h
vicNl.c
vicNl.h
vicNl_def.h
vicerror.c
water_energy_balance.c
wetland_energy.c
write_data.c
write_forcing_file.c

    Description:

    In earlier versions of VIC, the set of output files and their contents
    were hard-coded.  A few settings in user_def.h (OPTIMIZE and
LDAS_OUTPUT) allowed the user to change the contents of the output
files, but this has not been enough to accomodate the various needs of
users.  Users inevitably have had to modify write_data.c to produce the
type of output they want, and when VIC is updated, they must merge their
changes into the new version of the code.

    VIC 4.1.0 now allows the user to specify exactly which output files to
    create and which variables to store in each file.  This way, users can
    save space by only writing those variables that are useful, and will
be less likely to need to maintain a private version of the code to do
this.

In addition, VIC 4.1.0 can now aggregate the output variables to a
user-defined output interval, via the OUT_STEP setting in the global
parameter file.  Currently, the largest output interval allowed is 24
hours, so this option is only useful for simulations running at sub-
daily time steps.


    Main points:

    1. Output file names and contents can be specified in the global param
       file (see below).

    2. If you do not specify file names and contents in the global param
       file, VIC will produce the same set of output files that it has
       produced in earlier versions, namely "fluxes" and "snow" files,
   plus "fdepth" files if FROZEN_SOIL is TRUE and "snowband" files if
       PRT_SNOW_BAND is TRUE.  These files will have the same contents and
       format as in earlier versions.

    3. The OPTIMIZE and LDAS_OUTPUT options have been removed.  These
       output configurations can be selected with the proper set of
       instructions in the global param file.  (see the output.*.template
       files included in this distribution for more information.)

    4. If you do specify the file names and contents in the global param
   file, PRT_SNOW_BAND will have no effect.

    To specify file names and contents in the global param file, one
    should use the following format:

      (typical global param file contents here...)

      # Output File Contents
      N_OUTFILES    <n_outfiles>

      OUTFILE       <prefix>        <nvars>
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]

      OUTFILE       <prefix>        <nvars>
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]
      OUTVAR        <varname>       [<format>       <type>  <multiplier>]

    where
            <n_outfiles> = number of output files
            <prefix>     = name of the output file, NOT including latitude
                           and longitude
            <nvars>      = number of variables in the output file
            <varname>    = name of the variable (this must be one of the
                           output variable names listed in vicNl_def.h.)

            <format>, <type>, and <multiplier> are optional.  For a given
            variable, you can specify either NONE of these, or ALL of
            these.  If these are omitted, the default values will be used.

            <format>     = (for ascii output files) fprintf format string,
                           e.g.
                             %.4f = floating point with 4 decimal places
                             %.7e = scientific notation w/ 7 decimal
                             %places
                             *    = use the default format for this
                             *    variable
            <type>       = (for binary output files) data type code.
                           Must be one of:
                             OUT_TYPE_DOUBLE = double-precision floating
                       point
                             OUT_TYPE_FLOAT  = single-precision floating
                       point
                             OUT_TYPE_INT    = integer
                             OUT_TYPE_USINT  = unsigned short integer
                             OUT_TYPE_SINT   = short integer
                             OUT_TYPE_CHAR   = char
                             *               = use the default type
            <multiplier> = (for binary output files) factor to multiply
                           the data by before writing, to increase
                           precision.
                             *    = use the default multiplier for this
                             *    variable

    Here's an example.  To specify 2 output files, named "wbal" and
    "ebal", and containing water balance and energy balance terms,
    respectively, you could do something like this:

      N_OUTFILES    2

      OUTFILE       wbal    6
      OUTVAR        OUT_PREC
      OUTVAR        OUT_EVAP
      OUTVAR        OUT_RUNOFF
      OUTVAR        OUT_BASEFLOW
      OUTVAR        OUT_SWE
      OUTVAR        OUT_SOIL_MOIST

      OUTFILE       ebal    7
      OUTVAR        OUT_NET_SHORT
      OUTVAR        OUT_NET_LONG
      OUTVAR        OUT_LATENT
      OUTVAR        OUT_SENSIBLE
      OUTVAR        OUT_GRND_FLUX
      OUTVAR        OUT_SNOW_FLUX
      OUTVAR        OUT_ALBEDO

    Since no format, type, or multiplier were specified for any variables,
VIC will use the default format, type, and multiplier for the variables.

    If you wanted scientific notation with 10 significant digits for
ALBEDO, you could do the following:

      OUTVAR        OUT_ALBEDO              %.9e    *       *

    Note that even if you only want to specify the format, you must supply
a value in the type and multiplier columns as well.  This can be "*" to
indicate the default value.  Similarly, if you only want to specify the
type (e.g.  as a double), you would need to do something like:

      OUTVAR        OUT_ALBEDO              *       OUT_TYPE_DOUBLE *


    Date variables:

    For typical output files, the date is always written at the beginning
of each record.  This will consist of the following columns:
      year month day hour
    For daily output timestep, "hour" is not written.

    If BINARY_OUTPUT is TRUE, these will all be written as type int
(OUT_TYPE_INT).

    If OUTPUT_FORCE is TRUE, the date will NOT be written.


    Multiple-valued variables:

    Since variables like SOIL_MOIST have 1 value per soil layer, these
variables will be written to multiple columns in the output file, one
column per soil layer.  Other multiple-valued variables are treated
similarly.


    Snow band output:

    To specify writing the values of variables in each snow band,  append
    "_BAND" to the variable name (this only works for some variables - see
    the list in vicNl_def.h).  If you specify these variables, the value
of the variable in each band will be written, one band per column.  For
    example, for a cell having 2 snow bands:

      OUTVAR        OUT_SWE_BAND
      OUTVAR        OUT_ALBEDO_BAND

    will result in an output file containing:

      year month day (hour) swe[0] swe[1] albedo[0] albedo[1]

                                    TJB

Cleanup of structures holding filenames and file pointers

Files Affected:

check_files.c
check_state_file.c
close_files.c
display_current_settings.c
dist_prec.c
get_global_param.c
initialize_model_state.c
make_in_and_outfiles.c
open_state_file.c
read_initial_model_state.c
vicerror.c
vicNl.c
vicNl_def.h
vicNl.h
write_model_state.c

Description:

1. Merged infiles and outfiles structs into filep_struct.
2. Merged builtnames into filenames struct.
3. Renamed infiles.statefile to filep.init_state
4. Moved global.statename to filenames.statefile.
5. Added f_path_pfx[] to the filenames_struct, to store
   the path and prefix of forcing files.  Now, forcing[]
   only stores the full forcing file names.
                                    TJB

Soil thermal node temperature is now an output variable

Files Affected:

output_list_utils.c
put_data.c
vicNl_def.h

Description:

Soil thermal node temperature can now be selected for output, via the
key "OUT_SOIL_TNODE".  If selected, the temperatures at all valid soil
thermal nodes will be output.                       TJB

Removed LAKE_MODEL compile-time option

Files Affected:

check_files.c
display_current_settings.c
dist_prec.c
full_energy.c
get_global_param.c
IceEnergyBalance.c
ice_melt.c
initialize_lake.c
initialize_model_state.c
initialize_soil.c
LAKE.h
lakes.eb.c
make_dist_prcp.c
put_data.c
read_initial_model_state.c
read_lakeparam.c
user_def.h
vicNl.c
vicNl_def.h
vicNl.h
water_energy_balance.c
water_under_ice.c
wetland_energy.c
write_model_state.c

Description:

From a functional standpoint, the LAKE_MODEL compile-time option was
redundant with the options.LAKE switch.  Meanwhile, the difference in
the size of the executable between when the LAKE_MODEL switch was on
or off was deemed insignificant.  Therefore, this switch was removed
in the interest of making the code easier to maintain and reducing
user confusion.  Now, to turn off lake functionality, simply set LAKE
to FALSE in the global parameter file (or omit the "LAKE" line
completely).                                TJB

More complete set of supported input variables

    Files Affected:

    display_current_settings.c
    get_force_type.c
    get_force_type_pilps.c (removed)
    get_global_param.c
    initialize_atmos.c
    initialize_atmos_pilps.c (removed)
    initialize_global.c
    vicNl_def.h

    Description:

    Added REL_HUMID (relative humidity, as a fraction) to the list of
    supported met input variables.  Added the ALMA_INPUT option, which
    causes temperatures to be interpreted as Kelvin, pressures as kPa,
    and moisture fluxes as rates (mm/s) instead of accumulated fluxes
    (mm/timestep).  This allowed us to remove TAIR and PSURF from the
    list of supported met input variables, since AIR_TEMP and PRESSURE
    provide this ability when ALMA_INPUT is TRUE.  This also makes
    input variable specification more consistent with output variable
    specification.

    Since now the forcing files from PILPS can be read via the
    appropriate specification of input variables and ALMA_INPUT option
    in the global parameter file, the file initialize_atmos_pilps.c
    has been removed.                           TJB

Optional headers for output and input files

    Files Affected:

    display_current_settings.c
    get_global_param.c
    global.param.sample
    initialize_global.c
    Makefile
    read_atmos_data.c
    vicNl.c
    vicNl_def.h
    vicNl.h
    write_header.c (new)

    Description:

    Added the PRT_HEADER option to the global parameter file.  If
    this is set to TRUE, VIC will insert a short header into its
    output files, describing the time step, start date/time,
    variables and units included in the file.

    For ascii files, the output header has the following format:

            # NRECS: (nrecs)
            # DT: (dt)
            # STARTDATE: yyyy-mm-dd hh:00:00
            # ALMA_OUTPUT: (0 or 1)
            # NVARS: (Nvars)
            # VARNAME    VARNAME   VARNAME   ...

    where
       nrecs       = Number of records in the file
       dt          = Time step length in hours
       start date  = Date and time of first record of file
       ALMA_OUTPUT = Indicates units of the variables; 0 = standard VIC
                     units; 1 = ALMA units
       Nvars       = Number of variables in the file, including date
                     fields

    For binary files, the output header has the following format:

        // Data        Stored As           Comment
        //
        // Identifier  (unsigned short)*4  0xFFFF, repeated 4 times
        // Nbytes      (unsigned short)*1  Number of bytes in the header,
        //                                 INCLUDING THE IDENTIFIER
        //
        // Part 1: Global Attributes
        // Nbytes1     (unsigned short)*1  Number of bytes in part 1
        // nrecs       (int)*1             Number of records in the file
        // dt          (int)*1             Time step length in hours
        // startyear   (int)*1             Year of first record
        // startmonth  (int)*1             Month of first record
        // startday    (int)*1             Day of first record
        // starthour   (int)*1             Hour of first record
        // ALMA_OUTPUT (char)*1            0 = standard VIC units; 1 = ALMA units
        // Nvars       (char)*1            Number of variables in the file,
        // including date fields
        //
        // Part 2: Variables
        // Nbytes2     (unsigned short)*1  Number of bytes in part 2
        // For each variable, the following fields: { len varname type mult }
        //   len       (char)*1            Number of characters in varname
        //   varname   (char)*len          Variable name
        //   type      (char)*1            Code identifying variable type
        //   mult      (float)*1           Multiplier for variable


    To accomodate input forcing files that might have been produced via
    VIC's OUTPUT_FORCE option, and therefore could contain a header,
    read_atmos_data.c has been modified to detect and skip headers that
    follow the formats outlined above.                  TJB

Variable TYPE specifications for binary-format output files in the global parameter
file must match the strings listed in vicNl_def.h.

Files Affected:

parse_output_info.c

Description:

When listing output variables in the global parameter file, if the
output file format is binary, the variable data TYPE must match the string
from vicNl_def.h exactly, e.g. "OUT_TYPE_INT" rather than just "INT".   TJB

Added global option CONTINUEONERROR allowing simulation to continue on cell error.

Files Affected:

arno_evap.c
CalcAerodynamic.c
calc_atmos_energy_bal.c
CalcBlowingSnow.c
calc_rainonly.c
calc_surf_energy_bal.c
display_current_settings.c
dist_prec.c
frozen_soil.c
full_energy.c
func_surf_energy_bal.c
get_global_param.c
ice_melt.c
initialize_new_storm.c
lakes.eb.c
redistribute_during_storm.c
root_brent.c
runoff.c
snow_intercept.c
snow_melt.c
soil_conduction.c
solve_snow.c
surface_fluxes.c
vicNl.c
water_energy_balance.c
water_under_ice.c
wetland_energy.c
global.param.sample
LAKE.h
vicNl_def.h
vicNl.h

Description:

If the global option CONTINUEONERROR is set to TRUE then the
simulation continues to run even if a cell fails and produces
partial output. Default is is for CONTINUEONERROR to be FALSE,
as in previous versions of model. The return value of some modules
was changed from void to an int numeric return value. The ERROR
value is defined in vicNl_def.h.                    KAC via GCT

Exponential grid transformation option for soil thermal nodes in finite
difference heat equation

Files Affected:

calc_surf_energy_bal.c
display_current_settings.c
frozen_soil.c
func_surf_energy_bal.c
get_global_param.c
initialize_global.c
initialize_model_state.c
soil_conduction.c
soil_thermal_eqn.c
vicNl_def.h

Description:

New option is now EXP_TRANS to have an exponential distribution
of the thermal node depths in the vertical dimension.  This allows for
closer thermal nodes near the surface of soil where the variance is
greatest.  The transformation allows for the solution to be solved in
linear-space, wherein the nodes are distributed linearly with depth,
but the physical system exists in exponential space.  This change also
involves a rearranging of the terms in the finite-difference equaton
(equation 8 of Cherkauer et al. 1999).  Therefore the constants (A-E)
are calculated in a new way.  These constants are equal to the constants
in each of the terms in equation 8 multiplied by alpha^2*deltat.    JCA

Implicit solution option for finite difference frozen soils algorithm

Files Affected:

calc_surf_energy_bal.c
display_current_settings.c
frozen_soil.c
func_surf_energy_bal.c
get_global_param.c
initialize_global.c
Makefile
surface_fluxes.c
vicNl_def.h
vicNl.h

Description:

The implicit solution uses Newton Raphson to solve the system of non-
linear equations.  Therefore there is a new option, IMPLICIT.  If the
implicit solution fails (which can sometimes occur at the initial
formation of ice in the soil column), the model will use the original
explicit solver to solve for the thermal temperatures for that time
step only.  The implicit option is unconditionally stable and therefore
the Courant-Friedrichs-Lewy condition does not need to be checked (as
it should be for the explicit solver).                  JCA

Zsum_node calculated once and passed in soil_con to other subroutines

Files Affected:

calc_surf_energy_bal.c
func_surf_energy_bal.c
initialize_model_state.c
lakes.eb.c
read_initial_model_state.c
runoff.c
soil_conduction.c
vicNl_def.h
write_debug.c
write_model_state.c

Description:

Zsum_node is the depth of each of the thermal nodes needed
for the finite difference frozen soils algorithm.  Rather than re-
calculating this value in various places, this vector is now passed
in the soil_con structure to the various subroutines where it is
needed.  The one exception is set_node_parameters, because this is
a slightly different definition of Zsum.                JCA

Patch for "cold nose" problem

Files Affected:

frozen_soil.c
soil_thermal_eqn.c

Description:

This is an inelegant fix for "cold nose" problem that may occur in
the finite different frozen soil algorithm in each mode of operation.
This involves a thermal node that is of a lower temperature than the
upper and lower thermal nodes.  Due to the first term of the heat
conduction term (the term that accounts for a change in the thermal
conductivity in space), the first term can become more negative
than the second term. This causes this cold node to become
much colder and thus breaks the second law of thermodynamics (because
flux_term1 exceeds flux_term2 in absolute magnitude).  Therefore, a check
is now made to set the first term to zero when this begins to happen.
This only seems to happen in the first and second near-surface nodes.   JCA

Added EXCESS_ICE option (set in user_def.h)

Files Affected:

calc_surf_energy_bal.c
calc_water_energy_balance_errors.c
display_current_settings.c
frozen_soil.c
full_energy.c
func_surf_energy_bal.c
get_global_param.c
initialize_model_state.c
initialize_soil.c
LAKE.h
lakes.eb.c
output_list_utils.c
prepare_full_energy.c
put_data.c
read_initial_model_state.c
read_soilparam_arc.c
read_soilparam.c
runoff.c
soil_conduction.c
soil_thermal_eqn.c
surface_fluxes.c
user_def.h
vicNl.c
vicNl_def.h
vicNl.h
wetland_energy.c
write_model_state.c

Description:

If TRUE, VIC allows for excess ground ice, i.e. an expanded porosity
to account for an initial volumetric ice fraction larger than
soil porosity.  The ground subsides (therefore soil depth is no
longer static) and the porosity decreases as the excess ice melts.
Once porosity reaches the soil porosity (1-bulk density/soil density),
it does not change.  The initial volumetric ice fraction for
each soil layer must be defined in the soil file. The maximum value
for this initial ice fraction is set by MAX_ICE_INIT in
vicNl_def.h.  Another new parameter is ICE_AT_SUBSIDENCE, also set
in vicNl_def.h.  This parameter controls the rate of subsidence as
the ground warms.  Setting a larger value will cause the ground to
subside sooner and faster.  The physical bounds of this parameter
are 0.0 and 1.0, although setting this to a value of 1.0 will result
in the ground continually subsiding despite very cold soil
temperatures because there is always a small amount of unfrozen water
in each soil layer due to the function used in maximum_unfrozen_water.
The recommended value is 0.8.                       JCA

Bare soil evap for LAI=0

Files Affected:

func_surf_energy_bal.c

Description:

Modified to use arno_evap rather than canopy_evap if LAI
is 0, e.g. winter cropland.                     KAC via TJB

Drop canopy snow if thin

Files Affected:

snow_intercept.c

Description:

Modified to drop canopy snow if it is especially thin
(< MIN_SWQ_EB_THRES), which should improve the numeric
stability of the canopy energy balance solution.            KAC via TJB

Bug Fixes:

Various bugs in output variables

Files Affected:

global.param.sample
output_list_utils.c
output.PILPS-2E.ALMA.template
output.TRADITIONAL.410.template
output.TRADITIONAL.template
put_data.c
set_output_defaults.c
vicNl_def.h

Description:

1. Shortened the names of variables whose names were too long
2. Fixed typos in other names
3. Added OUT_IN_LONG
                                    TJB

Uninitialized value of ice[] in transpiration()

Files Affected:

canopy_evap.c

Description:

Modified to initialize ice[] for all soil layers before computing
available moisture (to avoid using uninitialized values later on).  TJB

Uninitialized value of mixdepth in solve_lake()

Files Affected:

lakes.eb.c

Description:

Now set mixdepth=0 for case of complete ice cover; this guarantees that
it is initialized for all cases.                    TJB

Incorrect sub-daily temperature interpolation when referencing GMT instead of
local time

Files Affected:

calc_air_temperature.c

Description:

Temperature interpolation didn't account for case in which min or max
temperature could cross the boundary of the current day.  This can
happen when referencing GMT instead of local time, for cells far away
from 0 E longitude.  This has been fixed.               TJB

Water budget errors in snow pack on top of lake ice

Files Affected:

lakes.eb.c

Description:

Convert swq and surf_water from mm over lake to mm over ice fraction at
beginning of solve_lake().  This was needed to avoid a water budget
error since swq and surf_water were being converted to mm over lake at
end of solve_lake().                            TJB

Incorrect filenames in Makefile for variable output list functions

Files Affected:

Makefile

Description:

Changed ".c" to ".o" for output_list_utils.o, parse_output_info.o,
set_output_defaults.o                           TJB

Output variable OUT_DELSURFSTOR not functioning

Files Affected:

output_list_utils.c
put_data.c

Description:

Default properties for OUT_DELSURFSTOR were not set in
output_list_utils.c, and OUT_DELSURFSTOR was not assigned a
value in put_data.c.  These problems have been fixed.           TJB

Pressure and vapor pressure output in wrong units

Files Affected:

put_data.c
write_forcing_file.c

Description:

The output variables pressure and vapor pressure were output in Pa
instead of kPa.  This has been fixed.                   TJB

Changed OUT_SURF_TEMP from the average of T[0] and T[1] to exactly
equal to T[0].

Files Affected:

put_data.c

Description:

Previously, OUT_SURF_TEMP had been set to the average of node
temperatures T[0] and T[1].  This has been changed to just T[0],
since OUT_SURF_TEMP represents the surface skin temperature.        TJB

Added case of SPATIAL_FROST = TRUE in full_energy.c

Files Affected:

full_energy.c

Description:

This module needed to handle the case of SPATIAL_FROST = TRUE.      GCT

Fixed fread statements

Files Affected:

read_initial_model_state.c

Description:

Fixed fread checks to make sure correct number of items were read
in rather than the size of the item read in.                JCA

Read in order incorrect in error_print_surf_energy_bal

Files Affected:
calc_surf_energy_bal.c
                                    GCT

Removed (1.-snow_coverage) from three equations where it did not belong

Files Affected:

func_surf_energy_bal.c
                                    GCT

setup_frozen_soil subroutine removed as it is never called

Files Affected:

frozen_soil.c
                                    GCT

Bug fix for previous bug fix to dt_baseflow calculation.

Files Affected:

runoff.c

Description:

Fixed bug arising from earlier fix to dt_baseflow
calculation.  Earlier fix took residual moisture
into account in the linear part of the baseflow eqn,
but not in the non-linear part.  Now we take residual
moisture into account correctly throughout the whole
equation.                               TJB

Sub-daily snow step for 24h wb mode not aggregating correctly

Files Affected:

snow_melt.c
solve_snow.c
surface_fluxes.c

Description:

The implementation of the canopy iteration in surface_fluxes() 
caused the data structures containing the results
for the sub-daily snow steps to be reset at the beginning
of every sub-daily step, resulting in large water
balance errors and incorrect daily results.  This has been fixed by
creating distinct data structures to store results for 
iterations (iter_*) and steps (step_*).  In addition,
the units of snow melt were corrected to
be consistent (mm) across functions.                    TJB

Moved Implicit error counting above call for solve_T_profile.

Files Affected:

func_surf_energy_bal.c
                                    GCT

Moved ARNO/NIJSSEN conversion after calculation of max_moist.

Files Affected:

read_soilparam_arc.c
                                    GCT

Added ErrorFlag return value from initialize_prcp.

Files Affected:

lakes.eb.c
LAKE.h
                                    GCT

Trap cases of T-errors matching variable ERROR for root_brent.

Files Affected:

calc_atmos_energy_bal.c
calc_surf_energy_bal.c
frozen_soil.c
ice_melt.c
root_brent.c
snow_intercept.c
snow_melt.c

Description:

Basically, what was happening was that when root_brent was called
from calc_surf_energy_bal with func_surf_energy_bal as Function,
then func_surf_energy_bal was ocasionally returning a value of ERROR to
root_brent, and root_brent was then (in some cases) interpreting
this as an actual surface temperature and continuing merrily on
its way. So, there was an error in the model that was never
caught. So, now root_brent checks for this and returns a value of
ERROR if there is a problem. Because of this change, all of the
routines that call root_brent had to be changed since they checked
against an error of -9998 - now they check for
values less than -998, since ERROR = -999.              JCA

Trap cases of negative soil moisture.

Files Affected:

full_energy.c

Description:

No longer resets ice content to previous time-step ice content if
subsidence has occurred.                        JCA

Fixed bug for read-in during EXCESS_ICE option.

Files Affected:

read_initial_model_state.c

Description:

Fixed bug for read-in during EXCESS_ICE option.             JCA

Memory errors for ARC_SOIL=TRUE and OUTPUT_FORCE=TRUE

Files Affected:

get_force_type.c
get_global_param.c
initialize_global.c
read_soilparam.c
read_soilparam_arc.c
vicNl.c

Description:

Memory errors would occur when ARC_SOIL=TRUE and OUTPUT_FORCE=TRUE.
In addition, the output files would not contain sufficient contents due
to not closing properly.  These have been fixed.            TJB

Handling of cells missing from snowband file

Files Affected:

read_snowband.c

Description:

Previously, if SNOW_BAND = TRUE and a particular cell was not listed
in the snowband file, VIC would abort.  Now, when VIC encounters
cells with no information in the snowband file, VIC issues a warning
and sets the cells to have 1 band, with Tfactor = 0 and Pfactor = 1.    KAC via TJB

Moved check for soil moisture > max to initialize_model_state.c

Files Affected:

read_initial_model_state.c
initialize_model_state.c

Description:

For initializing the model state the check for soil
moist > max moist was moved from read_initial_model_state.c
to initialize_model_state.c. The check is performed on all veg types
even if the area fraction = 0. There was a situation with
EXCESS_ICE = TRUE when the model was trying to distribute
moisture values that exceeded max moist to each thermal node
in the wetland area when Cl = 0.                    JCA

Incorrect limits on soil layer evap in runoff() for SPATIAL_FROST = TRUE

Files Affected:

runoff.c

Description:

Modified to correctly handle evaporation from spatially
distributed soil frost.  Original version could produce
negative soil moisture in fractions with high ice content
since only total evaporation was checked versus total
liquid water content, not versus available liquid water
in each frost subsection.                       KAC via TJB

Bug fixes in EXCESS_ICE calculations

Files Affected:

full_energy.c
vicNl_def.h

Description:

Added MAX_SUBSIDENCE parameter to EXCESS_ICE option.
Fixed bug in subsidence calculation.                    JCA

Return ERROR instead of exiting in ice_melt.c module

Files Affected:

ice_melt.c

Description:

Return ERROR instead of exiting, if ice_melt could not converge to
a solution in root_brent.                       JCA

Force runoff() to use user-specified resid_moist

Files Affected:

runoff.c

Description:

Removed logic that reset resid_moist[i].  Previously,
resid_moist[i] was reset to 0 for i > 0 when
resid_moist[0] == 0.  Such resetting of soil properties
was deemed unnecessary and confusing, since VIC would end
up using different residual moisture values than those
specified by the user.  If a user truly wants to specify
residual moisture in all layers to be 0, the user should
set these explicitly in the soil parameter file.  Also
fixed typo in fprintf() on line 289.                    TJB

Fixed error in EXP_TRANS formulation

Files Affected:

frozen_soil.c
soil_thermal_eqn.c

Description:

Fixed error in EXP_TRANS formulation.                   JCA

Updated default output file variable lists to match traditional 4.1.0
output files

Files Affected:

set_output_defaults.c

Description:

Updated to reflect variables present in traditional 4.1.0
output files.  Previously the defaults matched the traditional
4.0.6 output files.                         TJB

Model aborts when TIME_STEP = 24 and STARTHOUR is not specified.

Files Affected:

get_global_param.c

Description:

Added validation of dt, start date, end date, and nrecs.        TJB

Miscellaneous bugs in frozen soils.

Files Affected:

frozen_soil.c
soil_conduction.c

Description:

Fixed miscellaneous bugs (typos) in frozen soil equations.      JCA

Output file headers contain "hour" field despite output dt == 24 hours.

Files Affected:

write_header.c

Description:

Replaced all instances of global.dt with global.out_dt,
since out_dt is the time interval used in the output files.     TJB

Liquid soil moisture sometimes falls below residual.

Files Affected:

runoff.c

Description:

Fixed the checks on the lower bound of soil moisture.
Previously, the condition was
  (moist[lindex]+ice[lindex]) < resid_moist[lindex]
which led to liquid soil moisture falling below residual
during winter conditions.  This has been changed to
  moist[lindex] < resid_moist[lindex]
to eliminate these errors and make the logic consistent
with the rest of the code.                      TJB

Variable "moist" in runoff() has different meaning than in other functions.

Files Affected:

runoff.c

Description:

Renamed all *moist* variables to *liq* if they only refer
to liquid soil moisture.  This makes the logic much easier
to understand.                              TJB

Soil moisture drops below residual for sub-daily time step interval and
FULL_ENERGY or FROZEN_SOIL = TRUE.

Files Affected:

runoff.c

Description:

Fixed the checks on the lower bound of soil moisture.  Previously,
the lower bound on soil moisture was
  (liquid + ice >= residual moisture)
and the way this bound was enforced was to reduce baseflow to
bring total liquid + ice content back up to residual, but this
compensation was limited so that the compensation would never
be larger than baseflow (i.e. the compensation would never create
negative baseflow).

However, this condition had two main problems: 1. it allowed liquid
moisture to fall to very low values (due to evap being over-estimated
in arno_evap() and transpiration(), and/or Q12 being over-estimated
earlier in runoff() due to bad numerics) in the presence of ice, and
2.  it had limited ability to recover from these low values because
baseflow (already small) wasn't allowed to be reduced below 0.

This behavior has been replaced with the following conditions: For
unfrozen soil, the new lower bound is
  (liquid >= resid_moist)
while for frozen soil, the new error condition is
  (liquid >= min_liq_fraction * resid_moist)
where
  min_liq_fraction = the value returned by maximum_unfrozen_water()
                     for a unit maximum moisture content.

If overestimates of evap or drainage do occur, baseflow is allowed
to be reduced below 0 to bring liquid water back up to the lower
limit.  Then, further down in the code, if baseflow is negative,
bottom-layer evap is reduced by (-baseflow) and baseflow is set to 0.   TJB

* Description of changes from VIC 4.1.0 beta r2 to VIC 4.1.0 beta r3 *

New Features:

Improved lake model

Files Affected:
CalcBlowingSnow.c, LAKE.h, IceEnergyBalance.c, ice_melt.c,
initialize_atmos.c, initialize_lake.c, lakes.eb.c, read_lakeparam.c,
solve_snow.c, surface_fluxes.c, vicNl.h, vicNl_def.h,
water_energy_balance.c, water_under_ice.c

Description:
This fixes the following bugs:

    Lake model crashes when lakes fill up
    Lake model crashes when lakes dry out

And introduces the following new features:

    Blowing snow sublimation computed over lakes
    Tuning of default lake profile (parabolic to square)

The new parameter BETA in LAKE.h can be used to control the shape of the
automatic lake profile (when the global option LAKE_PROFILE is FALSE).
BETA=0.5 is strongly parabolic, while BETA=0.001 is almost square
(vertical walls).

If LAKE_PROFILE=FALSE, the lake parameter file from VIC 4.1.0 beta 2 can
be used without any changes.  However, if LAKE_PROFILE=TRUE, the lake
parameter file must now contain a (depth,area) pair for each lake node.
See read_lakeparam.c for details.

VIC now supports ALMA input and output variables.

Files Affected:
Makefile, conv_force_vic2alma.c, conv_results_vic2alma.c, close_files.c,
display_current_settings.c, dist_prec.c, get_force_type.c,
get_global_param.c, initialize_atmos.c, initialize_global.c,
make_in_and_outfiles.c, put_data.c, read_atmos_data.c, vicNl.h,
vicNl_def.h, write_data.c, write_forcing_file.c

Description:
VIC now supports ALMA input and output variables.  To have VIC read ALMA
input (forcing) variables, all that is required is to identify them by
the appropriate names in the forcing section of the global parameter file.
The appropriate names are listed in vicNl_def.h.  To have VIC write ALMA
output variables, it is necessary to include the option ALMA_OUTPUT in the
global parameter file and set it to TRUE.  This option does not affect
model physics.

State file is now written at the END of the final timestep of the date indicated
in the global parameter file.

Files Affected:
dist_prec.c

Description:
Previous versions of VIC wrote the state file at the beginnning of the
date indicated (via STATEYEAR, STATEMONTH, and STATEDAY) in the global
parameter file.  For sub-daily model time steps, this meant that the
simulation's end could not be aligned exactly with the writing of the
state file, since the model would continue simluating for the remainder
of the final day after writing the state file.  This created difficulties
when running VIC in real-time simulations, in which the forcings are
broken up into short time periods and the previous state file must be
used as the initial condition for the next time period.

Now that the state file is written at the end of the final timestep of the
date indicated in the global parameter file, it is possible for the end of
a forcing file, the end of the simulation, and the timing of the state file
all to align on the same time.  This simplifies re-starting the model for
a forcing file that begins immediately after the previous forcing file
ended, since the state file now is equivalent to the initial condition at
the beginning of the new forcing file.

EQUAL_AREA global parameter option

Files Affected:
display_current_settings.c, get_global_param.c, initialize_global.c,
read_lakeparam.c, vicNl_def.h

Description:
New global parameter option.  When EQUAL_AREA is TRUE, all grid cells are
assumed to have the same area, and the global parameter RESOLUTION is
interpreted to store the grid cell area in km^2.  When EQUAL_AREA is FALSE,
grid cells are assumed to have the same side length in degrees, and
RESOLUTION is interpreted to store the grid cell side length in degrees,
as before.

New vicInterp executable

Files Affected:
Makefile, check_files.c, close_files.c, get_global_param.c,
read_soilparam.c, vicNl.c

Description:
Now users can create a stand-alone executable called "vicInterp" by
typing "make interp".  This executable is a stripped-down version 
of VIC that reads a set of forcing files and outputs diurnally-varying
sub-daily forcings.  The interpolation scheme, based on the Thornton and
Running (mtclim) algorithm, can convert from from daily Prec, Tmin, Tmax,
and Wind to sub-daily Prec, AirTemp, Shortwave and Longwave radiation,
Wind, Pressure, and air Density.  The interpolated forms of Prec, Wind,
Pressure, and Density do not vary diurnally but are assumed constant
during each day.

vicInterp is vicNl, compiled with the OUTPUT_FORCE option set to TRUE.
As such, vicInterp can read a standard VIC global parameter file.  While
it will ignore many of the options, it understands (and requires) the
following:
    TIMESTEP
    STARTYEAR
    STARTMONTH
    STARTDAY
    STARTHOUR
    ENDYEAR
    ENDMONTH
    ENDDAY
    GRID_DECIMAL
    FORCING1
    N_TYPES
    FORCE_TYPE
    FORCE_FORMAT
    FORCE_ENDIAN
    FORCE_DT
    FORCEYEAR
    FORCEMONTH
    FORCEDAY
    FORCEHOUR
    SOIL
    RESULT_DIR
In addition, the following options are optional:
    BINARY_OUTPUT
    ALMA_OUTPUT

For example, if FORCE_DT is 24 and TIMESTEP is 3, vicInterp will
interpolate the input daily forcings to a 3-hour time step.  If
ALMA_OUTPUT is TRUE, these output forcings will be standard ALMA
variables.

This new feature also involves an update to the OUTPUT_FORCE option
that fixes a bug in which output files were not properly closed
before exiting.  This prevented all of the output data from being
completely written.

Bug Fixes:

Large water balance errors in daily water balance mode when snow is present

Files Affected:
surface_fluxes.c

Description:
Fixed broken snow step in surface_fluxes.c.  Per-snow-step snow
quantities were being reset at the beginning of each canopy-surface
energy balance iteration, preventing snow characteristics from being
accumulated over all snow steps, and resulting in large water balance
errors.  Now per-iteration snow quantities are stored separately
from per-snow-step quantities.

Aerodynamic resistance incorrect in output fluxes file

    Files Affected:
    IceEnergyBalance.c, LAKE.h, SnowPackEnergyBalance.c,
    calc_surf_energy_bal.c, full_energy.c, func_canopy_energy_bal.c,
    func_surf_energy_bal.c, ice_melt.c, lakes.eb.c, put_data.c,
    snow_intercept.c, snow_melt.c, solve_snow.c, surface_fluxes.c,
    vicNl.h, vicNl_def.h, wetland_energy.c

    Description:
    In 4.1.0 beta r2 and earlier, the aerodynamic resistance written to the
    output fluxes file rarely reflected the value actually used in flux
    computations.  This has been fixed.

    VIC actually computes an array of 3 different aerodynamic resistances,
    as follows:
      aero_resist[0] : over vegetation or bare soil
      aero_resist[1] : over snow-filled overstory
      aero_resist[2] : over snow pack
    VIC determines which element of the array to use depending on the
current vegetation type and whether snow is present.  In addition, in
most cases, VIC applies a stability correction to this aerodynamic
resistance before using it in flux computations.  Furthermore, when the
current vegetation tile contains overstory and snow is present on the
ground, aero_resist[2] is used for snow pack flux computations and
either aero_resist[1] or aero_resist[0] is used for canopy flux
computations, meaning that two different aerodynamic resistances are in
use in the same time step.

    However, VIC 4.1.0 beta r2 always wrote the uncorrected value of
    aero_resist[0] to the fluxes file.

    In 4.1.0 beta r3 and later, the value written to the fluxes file is the
    actual value used in flux computations, including any corrections that
    were applied.  In the case mentioned above in which two different
    aerodynamic resistances are in use at the same time, the one used for
    the snow pack is written.  In addition, the aerodynamic resistance of
    the canopy air/surrounding atmosphere interface is not tracked.

Aerodynamic resistance not correctly aggregated for output

Files Affected:
conv_results_vic2alma.c, put_data.c, vicNl_def.h

Description:
In previous releases, aerodynamic resistance (out_data->aero_resist)
was aggregated by a simple area-weighted average over veg tiles.  This
led to an aggregate value that was not the true effective resistance
of the entire grid cell.  Since evaporation is proportional to
1/aero_resist, it is (1/aero_resist), or the aerodynamic conductivity,
that should be averaged over the grid cell.  Therefore, a new variable,
out_data.aero_cond, was created for the purposes of aggregation.  After
aggregation, out_data.aero_resist is computed as 1/out_data.aero_cond.

The effect of the change is most pronounced when there is a large range
of values of aerodynamic resistance among the veg tiles in a grid cell.
The effective aerodynamic resistance, computed the new way, will tend
to be smaller than the old way when the values cover a wide range.
However, the effective aerodynamic resistance will never be smaller than
the smallest value among the various veg tiles in the cell.

State variables for SPATIAL_FROST and LAKE_MODEL options not stored in state
file.

Files Affected:
dist_prec.c, initialize_model_state.c, read_initial_model_state.c,
vicNl.h, write_model_state.c

Description:
State variables for SPATIAL_FROST and LAKE_MODEL options were not stored
in state files, causing these variables to be reset to default values
when reading from an initial state file.  This has been fixed.

NOTE: this fix involves a change in the format of state files which
makes state files used with 4.1.0 beta 3 incompatible with earlier
releases (and vice versa).

ARNO_PARAMS global parameter option changed to BASEFLOW

    Files Affected:
    display_current_settings.c
    get_global_param.c
    global.param.sample
    initialize_global.c
    read_soilparam.c
    read_soilparam_arc.c
    vicNl_def.h

    Changed the name of the ARNO_PARAMS global parameter option to
    BASEFLOW.  The meaning of the ARNO_PARAMS option was actually
    opposite to its name: when ARNO_PARAMS was FALSE, VIC would
    interpret the first four parameters in the soil parameter file
    to be the standard ARNO soil parameters Ds, Dsmax, Ws, and c,
    while when ARNO_PARAMS was TRUE, VIC would interpret the first
    four parameters to be d1, d2, d3, and d4, the soil parameters
    used in Nijssen et al. (2001).  The new option now can take
    values of "ARNO" and "NIJSSEN2001".  When BASEFLOW == NIJSSEN2001,
    VIC assumes the soil parameter file contains d1, d2, d3, and d4.
    When BASEFLOW == ARNO, VIC assumes the soil parameter file
    contains Ds, Dsmax, Ws, and c.

Removed some snowband output

Files Affected:
write_data.c

Description:
    Removed  net sw radiation, net lw, albedo, latent heat flux, 
sensible heat flux, ground heat flux

STATE file option is now specified in global file, not in user_def.h at compile time

    Files Affected:

    display_current_settings.c
    dist_prec.c
    get_global_param.c
    initialize_global.c
    open_state_file.c
    user_def.h
    vicNl.c
    vicNl.h
    vicNl_def.h
    write_model_state.c

    Previously, to be able to read/write state files, VIC required
    users to define SAVE_STATE to be TRUE in user_def.h and
    recompile VIC, in addition to having the correct settings of
    INIT_STATE, STATENAME, STATEYEAR, STATEMONTH, and STATEDAY in
    the global parameter file.

    This was both unnecessary and confusing.  Setting SAVE_STATE
    to FALSE did not improve VIC performance noticeably, and
    having both a SAVE_STATE compile option and state file
    information in the global parameter file only led to mistakes
    in which the user made a change in one place without realizing
    a change needed to be made elsewhere.

    Now VIC behaves as follows:
    1. To read an initial state file, the following line
    must be in the global parameter file:
      INIT_STATE init_state_filename

    where init_state_filename is the name of the initial state
    file.  If this line is absent or commented out (preceded by a
    "#"), VIC will start from default initial conditions.

    2. To write a state file during the simulation, the
    following lines must be in the global parameter file:
      STATENAME  state_file_name
      STATEYEAR  state_year
      STATEMONTH state_month
      STATEDAY   state_day

    where state_file_name is the path and prefix of the file to
    save the state information in (the simulation date on which
    the state file is saved will be appended to the state file
    name), and state_year, state_month, and state_day are the
    year, month, and day of the simulation on which to save state.
    The state will be saved AFTER the FINAL time step of that
    date.  If all of these lines are absent or commented out, VIC
    will not save a state file.  If some (but not all) of these
    lines are present, VIC will give an error.

Now reads extra_veg from state file

    Files Affected:
    read_initial_model_state.c

Reverting from version 5.10 to 5.9 in surface_fluxes.c

    Files Affected:
    surface_fluxes.c

    Energy balance errors had been introduced in the changes from 5.9 to 5.10.
    This is an intermittent problem that appears to depend on versions of FreeBSD
    when compiling with the optimization flag. This temporary reversion should
    be okay as long as the time steps are sub-daily.  GCT

Skip reading/writing of snow band for areafract <= 0

    Files Affected:
    read_initial_model_state.c
    write_model_state.c

    This will reduce the size of the statefile. GCT

Lake model energy terms NaN for southern hemisphere lakes

    Files Affected:
    lakes.eb.c

    The computation of ks in the eddy() function was attempting to compute
  ks=6.6*pow(sin((double)lat*PI/180.),0.5)*pow(wind,-1.84);
however, in the southern hemisphere, lat is negative and ks evaluates
to NaN, causing lake temperatures to all become NaN.  This line has
been replaced by
  ks=6.6*pow(sin((double)fabs(lat)*PI/180.),0.5)*pow(wind,-1.84);
This appears to fix the problem.    TJB

Miscellaneous fixes for memory leaks and uninitialized variables.

    Files Affected:

    free_dist_prcp.c
    get_global_param.c
    initialize_lake.c
    initialize_model_state.c
    lakes.eb.c
    make_dmy.c
    mtclim42_vic.c
    output_list_utils.c
    parse_output_info.c
    put_data.c
    read_veglib.c
    solve_snow.c
    vicNl.c
    vicNl.h

    Description:

    Miscellaneous fixes for memory leaks and uninitialized variables.
    Also changed comments in vicNl.h to reflect type changes introduced
    in 4.1.0._r4h   TJB

* Description of changes from VIC 4.1.0 beta r1 to VIC 4.1.0 beta r2 *

New Features:

"-v" and "-o" command-line options and display of run/compile-time options

    Files Affected:
    cmd_proc.c, display_current_settings.c, get_global_param.c, global.h,
    vicNl.c, vicNl.h, vicNl_def.h

    Description:
    In VIC 4.1.0 beta r2, if VERBOSE is TRUE, all compile-time options (from
    user_def.h) and run-time options (from your global parameter file) are
    displayed for you at the beginning of a model run.  If you are saving
    your model output to a log file, this information will be stored with
    your log, so you will have a record of the option settings that produced
    the results of that particular model run.

The new "-v" option will display the release number of your vicNl
executable.  For example, typing:
    vicNl -v
gives
    ***** VIC Version 4.1.0 Beta Release 2 *****

    Meanwhile, the new "-o" option displays the current compile-time
    options.  One benefit of this option is that you can see what the
    options in user_def.h were set to when vicNl was compiled, without
    having to start a model run.  Since your version of user_def.h may have
    changed since you compiled vicNl, this is the most reliable way to see
    what these options are set to.  For example:

gen.hydro.washington.edu 175: vicNl -o

***** VIC Version 4.1.0 Beta Release 2 - Current Model Settings *****

COMPILE-TIME OPTIONS (set in user_def.h)
----------------------------------------

Output to Screen:
OUTPUT_FORCE_STATS      FALSE
VERBOSE                 TRUE

Input Files:
NO_REWIND               TRUE

Output Files:
LDAS_OUTPUT             FALSE
LINK_DEBUG              FALSE
OPTIMIZE                FALSE
OUTPUT_FORCE            FALSE
SAVE_STATE              FALSE

Simulation Parameters:
CLOSE_ENERGY            FALSE
COMPUTE_TREELINE        FALSE
LAKE_MODEL              FALSE
LOW_RES_MOIST           FALSE
QUICK_FS                FALSE
SPATIAL_FROST           FALSE
SPATIAL_SNOW            FALSE

Maximum Array Sizes:
MAX_BANDS               10
MAX_FRONTS               3
MAX_LAKE_NODES          20
MAX_LAYERS               3
MAX_NODES               18
MAX_VEG                 12

Snow Constants:
NEW_SNOW_ALB            0.850000
SNOW_ALB_ACCUM_A        0.940000
SNOW_ALB_ACCUM_B        0.580000
SNOW_ALB_THAW_A         0.820000
SNOW_ALB_THAW_B         0.460000
TraceSnow               0.030000

Other Constants:
LAI_WATER_FACTOR        0.200000
LWAVE_COR               1.000000
MAXIT_FE                25

Automatic recompilation on updates to *.h

    Files Affected:
    Makefile

    Description:
    In VIC 4.1.0 beta r1, updating a .h file and recompiling VIC would not
result in recompilation of files that depend on the .h file, unless a
"make clean" command was issued first.  Now, if any .h files are
    updated, all dependent .c files are recompiled on the next "make".

NEW_ARNO_TYPE global option is now ARNO_PARAMS

Files Affected:
get_global_param.c, read_soilparam.c, vicNl_def.h

Description:
Changed the name of the global option NEW_ARNO_TYPE to be ARNO_PARAMS.
"NEW_ARNO_TYPE" is confusing, since this option will not be new
forever, and doesn't refer to a "type" but rather a set of parameters.

NOTE: This change requires the user to replace all occurrences of
"NEW_ARNO_TYPE" in their global control files with "ARNO_PARAMS".

Bug Fixes:

Spurious condensation at low temperatures

    Files Affected:
    arno_evap.c

    Description:
    Changed logic of evap limit check to avoid creating spurious
    condensation.  In VIC 4.1.0 beta r1, whenever evaporation > (liquid
    moisture - residual moisture), evaporation would be set to (liquid
    moisture - residual moisture).  However, at low temperatures, when most
    or all soil moisture is frozen, liquid moisture < residual moisture,
    causing (liquid moisture - residual moisture) to be negative.  Any non-
    negative evap would be greater than this, resulting in evap getting set
    to (liquid moisture - residual moisture), which would be negative (i.e.
    condensation).  This artificially created condensation in whatever
    amount necessary to bring liquid moisture up to residual, causing 1)
    large latent heat flux, 2) incorrect surface temperatures, 3) occasional
    inability for calc_surf_energy_bal to converge in root_brent, and 4)
    spuriously high runoff and baseflow.  Now there is an added condition
    that liquid moisture > residual moisture for evap to be capped at
    (liquid moisture - residual moisture).

    NOTE: This fix results in lower runoff and baseflow in unvegetated areas
    with frozen soils, and may require recalibration of soil parameters.

Incorrect baseflow limits

    Files Affected:
    runoff.c

    Description:
    In 4.1.0 beta r1, runoff.c checked for the wrong bounds on baseflow,
    allowing baseflow to become negative when liquid soil moisture < residual
    moisture.  These bounds have been fixed in 4.1.0 beta r2, as follows:
    baseflow is not allowed to exceed (liquid soil moisture - residual moisture);
    when baseflow < 0, baseflow is set to 0; when baseflow > 0 and the resulting
    soil moisture < residual moisture, water is taken out of baseflow and
    given to the soil as follows:
      if baseflow > (residual moisture - soil moisture), then
        baseflow -= (residual moisture - soil moisture);
        soil moisture += (residual moisture - soil moisture);
      else
        soil moisture += baseflow;
        baseflow = 0;

    NOTE: This fix may result in small changes in baseflow and evaporation.

Runs using initial state files starting at state file date rather than global
start date

    Files Affected:
    check_state_file.c

    Description:
    In 4.1.0 beta r1, check_state_file.c would increment the index of the
    forcing data array until it reached the record corresponding to the date
    stored in the state file.  This caused the simulation to start at the
    date at which the state file was saved rather than the start date
    specified in the global parameter file.  If the state file's date was
    earlier than the start date in the global parameter file, the index
    would be incremented until a segmentation fault occurred.  This has
    been fixed in 4.1.0 beta r2 so that the start date in the global parameter
    file is always the start date of the simulation.  The date stored in
    the initial state file is ignored.

    NOTE: If you have been relying on the state file to dictate when your
    simulations start, this fix may require you to change your global
    parameter file so that STARTYEAR, STARTMONTH, etc. reflect the start
    date/time you want.

Incorrect sublimation values for BLOWING option

Files Affected:
CalcBlowingSnow.c, IceEnergyBalance.c, SnowPackEnergyBalance.c,
calc_surf_energy_bal.c, func_surf_energy_bal.c, ice_melt.c, lakes.eb.c,
latent_heat_from_snow.c, put_data.c, snow_melt.c, solve_snow.c,
surface_fluxes.c, vicNl.h, vicNl_def.h

Description:
Fixed 3 bugs in the sublimation terms: 1) sub_surface was wrong when
snow step was not 1 hour, 2) sub_blowing was wrong under certain
conditions, and 3) sub_blowing and sub_surface did not contain the
contribution from lakes, even though sub_total did.  The fix
establishes the convention that the internal variables VaporMassFlux,
BlowingMassFlux, and SurfaceMassFlux always have units of kg/m2s; and
that internal variables vapor_flux, blowing_flux, and surface_flux
always have units of m/timestep.  Unnecessary terms were removed from
the parameter lists of several functions.

NOTE: The effects of this fix on major water balance terms such as
runoff, baseflow, evaporation, etc. should be very small.

NOTE 2: The lake contribution to sub_blowing is currently set to 0.

Negative incoming shortwave radiation at high latitudes

    Files Affected:
    mtclim42_vic.c

    Description:
    In 4.1.0 beta r1, when sub-daily shortwave radiation is estimated from
    daily min/max temperatures, negative values occasionally are calculated
    in coastal areas above the Arctic Circle in winter.  Now, if estimated
    sub-daily incident shortwave is negative, it is set to 0.0.

Undefined daily precipitation for deserts

    Files Affected:
    mtclim42_vic.c

    Description:
    In 4.1.0 beta r1, if a grid cell's annual precipitation (specified in
    the soil parameter file) is 0, then the adjusted daily precipitation
    calculated in mtclim42_vic.c ends up being undefined.  In 4.1.0 beta r2
    this has been fixed.

    More specifically, the MTCLIM 4.2 algorithm (which VIC uses for
    estimating sub-daily forcing values) was originally set up to expect a
    base precipitation as an input, and to translate this base precip into
    a site-specific precip via an adjustment function.  The adjustment
    function multiplies the base precip by the ratio of site_isohyet to
    base_isohyet to get site precipitation.  In calling the MTCLIM 4.2
    functions, VIC sets site_isohyet and base_isohyet to the grid cell's
    annual precipitation.  So this ratio should always = 1.  However,
    when annual precipitation is 0.0, this ratio is undefined.  So, the
    fix is to set the ratio to 1 when both site_isohyet and base_isohyet
    are 0 (or very small). (found by Liz Clark)

Snow_flux incorrectly set to Tcanopy in fluxes output file

Files Affected:
put_data.c

Description:
In 4.1.0 beta r1, the snow_flux output variable was incorrectly set to
Tcanopy.  This has been corrected.

Incorrect value for sub_snow in fluxes output file

Files Affected:
write_data.c

Description:
Replaced output of sub_snow[0] in fluxes file with sub_total.

Special case in Penman equation

    Files Affected:
    penman.c

    Description:
    Changed
            if (vpd > 0.0 && evap < 0.0)
    to
            if (vpd >= 0.0 && evap < 0.0)
    to correctly handle evap when vpd == 0.0. (found by Justin Sheffield
    at Princeton)

Rint() function not supported on all platforms

    Files Affected:
    compute_dz.c, initialize_atmos.c, read_soilparam.c,
    read_soilparam_arc.c

    Description:
    Replaced rint(something) with (float)(int)(something + 0.5) to
    handle rounding without resorting to rint(), which isn't supported
    on all platforms.  (found by Justin Sheffield at Princeton)

Global parameter initialization

    Files Affected:
    initialize_global.c

    Description:
    Initialize ARC_SOIL, COMPRESS, and ARNO_PARAMS to FALSE.  Also changed
    limit on loop over forcing types from hard-coded 17 to variable
    N_FORCING_TYPES.  (found by Justin Sheffield at Princeton)

Bottom soil node thickness initialization

    Files Affected:
    initialize_model_state.c

    Description:
    Initialize soil_con->dz_node[Nnodes] to 0.0, since it is accessed in
    set_node_parameters().  (found by Justin Sheffield at Princeton)

Canopy evaporation and distributed precipitation

    Files Affected:
    surface_fluxes.c

    Description:
    Fixed initialization of canopyevap to initialize for every value of
    dist, rather than just dist 0. (found by Justin Sheffield at Princeton)

Output debug file error

    Files Affected:
    write_atmosdata.c

    Description:
    No longer close the debug file, since the next cell must write to it.
    (found by Justin Sheffield at Princeton)

Calculation of deltaH when FS_ACTIVE is FALSE

    Files Affected:
    func_surf_energy_bal.c

    Description:
    Added check that both FS_ACTIVE and FROZEN_SOIL are true before
    adjusting *deltaH.  This is just a safety measure; ice and ice0 should
    both be 0 when FS_ACTIVE is FALSE.  (found by Justin Sheffield at
    Princeton)

Root_brent error message clarification

    Files Affected:
    calc_atmos_energy_bal.c, calc_surf_energy_bal.c, frozen_soil.c,
ice_melt.c, root_brent.c, snow_intercept.c, snow_melt.c, vicNl.h

    Description:
    Instead of printing warning or error messages, root_brent.c now
passes descriptions of the errors to the functions that called it,
    leaving it to them to describe the specific error and its consequences.
In 4.0.4, root_brent's messages sometimes were wrong.

Display current grid cell number for arc/info soil files

    Files Affected:
    read_soilparam_arc.c

    Description:
    In 4.1.0 beta r1, for arc/info-format soil files, the current grid
    cell is not displayed (for regular-format soil files, it is displayed).
    Now the current grid cell number is always displayed.

Inconsistent format in state file

Files Affected:
write_model_state.c

Description:
Removed initial space on veg/band info line in ASCII file.

Pending Issues:

Lake model crashes when lake level gets too high

Lake model crashes when lake level gets too low

COMPUTE_TREELINE option non-functional

Description:
This issue is waiting for completion of a treeline-computation scheme
that allows landcover fractions to be stated explicitly as a function
of elevation band.

Lakes smeared across multiple elevation bands

Description:
Currently, VIC assumes that the percentage of grid cell area covered by
lakes is constant throughout the grid cell, and therefore when multiple
elevation bands are specified for a grid cell, the lake percentage is
distributed evenly across all elevations.  However, when modeling large
lakes, this assumption does not hold; the bulk of the lake coverage may
be due to a single large lake, which by definition cannot exist in
multiple elevation bands.  Therefore, we need a way of explicitly
specifying lake coverage as a function of elevation.

Updates 7-30-2003: VIC 4.1.0 r1

(1) Added support for ASCII as well as Binary state files (NOTE: ASCII
state files were added for easier editing when trying to start the 
model from observed state - Only Binary state files will produce
identical runs if used to store and restart from the model state).
Added BINARY_STATE_FILE to the global file, if TRUE state file I/O
is in binary, if FALSE it is ASCII.
(2) Made certain that local NOFLUX flag is set in calc_surf_energy_bal.c
every time the routine is executed.
(3) write_data.c: Corrected output of sub_snow variable to item [0] 
rather than a point - will need to decide what parts of this array 
are important to output.
(4) Modified runoff.c so that only the top two layers are used when
computing infiltration.  Previously, all but the bottom layer was 
used.  Therefore this only affects you if you tried running with
more than three layers.  This change was made as it makes more sense 
for a situation where you are trying to improve the representation
    of the soil column by increasing the resolution (and perhaps depth)
of the soil column.
(5) snow_utility.c (snow_density): Added check to keep compression from 
aging from exceeding the actual depth of the snowpack.
(6) solve_snow.c: Added check so that MELTING flag is only TRUE if melt
    occurs in the melt season - currently this is defined between March 1 
and October 1.  Otherwise the MELTING flag can trigger rapid very 
early season melt.

Updates 4-21-2003: Mering codes to form VIC 4.1.0 r0

From comparison of LatestAdminSource and LatestTestSource

Dynamic allocation of as many arrays and structures as are currently 
used by the VIC model cause electric fence (a memory debugging tool)
to bog down/fail in the allocation process.  As the allocation of
memory is unlikely to be the cause of new memory errors, hard wired 
memory can be used instead, letting eleectric fence penetrate further
into the code.
alloc_atmos.c: (KAC) MEMORY_DEBUG update
Modified so that dynamic allocation of the atmospheric data arrays
does not occur when the debugging code is linked to the model.  
This makes it possible to use electric fence to debug memory errors
without changing the model code.  Previously, dynamic allocation
of the atmospheric arrays was only skipped if VIC was configured 
for optimization work.
vicNl_def.h: (KAC) MEMORY_DEBUG update
    See alloc_atmos.c.

Newest version of the model had water balance errors when using 
distributed precipitation.  Model crashes were also witnessed.  Fixed
errors introduced by other model updates.
arno_evap.c: (KAC) DIST_PRCP fix
Moved unit conversion of moist_resid outside of the distributed
precipitation loop.  This prevents it from being multiplied by 
D1 * 1000 twice for the DRY fraction of the grid cell.
initialize_model_state.c: (KAC) DIST_PRCP fix
    Modified to initialize soil and vegetation parameters for the dry 
grid cell fraction, if distributed precipitation is activated.
snow_intercept.c: (KAC) DIST_PRCP fix
    Added check of intercepted before mass balance error calculation.  
Since interception quantity can be greater than Wd_max when snow 
is present, the routine could return dew values higher than maximum 
in a time step when intercepted snow melted.  If there is no other 
snow, and distributed precipitation is active this could cause the 
model to crash in redistribute_during_storm as it will be unable to 
conserve water when too much water is in the canopy.

** Make sure that all updates from surface_fluxes.c are accounted for
after merge with 4.0.4beta **

From comparison of LatestAdminSource (updated above) and LaurasNewestSource

IceEnergyBalance.c: (LCB) LAKE_WETLAND updates
    SnowFlux variable renamed to qf to match the lake-ice model 
documentation.
LAKE.h: (LCB) LAKE_WETLAND updates
    Modified some model parameters (need to check with Laura as to their
applicability outside dissertation basins).  Also updated profiles
for several subroutines.
SnowPackEnergyBalance.c: (KAC) OTHER
    Certain constant definitions have been moved to vicNl_def.h to 
standardize the location of model constants.  This is especially 
useful for eliminating redundant and unused constant definitions.
SnowPackEnergyBalance.c: (LCB) BLOWING_SNOW update
    New variables are passed to the routine and along to 
latent_heat_from_snow to add the effects of blowing snow to the
accumulation and ablation of the snowpack.
calc_surf_energy_bal.c: (LCB) BLOWING_SNOW update
    Modified to include the effects of blowing snow in the surface 
energy balance calulations.
close_files.c: (LCB) LAKE_WETLAND updates
    Now closes the lake and wetland debugging file.
full_energy.c: (LCB) BLOWING_SNOW updates
    Modified to handle blowing snow.
full_energy.c: (LCB) LAKE_WETLAND updates
Modified to output lake model variables during debugging.
func_surf_energy_bal.c: (LCB) BLOWING_SNOW updates
    Modified to handle blowing snow.
func_surf_energy_bal.c: (KAC) OTHER
    Modified so that the calculation of sensible heat flux so that 
occurs in all model versions.  This eliminates a problem in
WB mode where sensible heat flux was not set to 0, instead it
showed the cumulative sensible heat flux from the snowpack.
get_global_param.c: (LCB) BLOWING_SNOW update
    Added BLOWING_SNOW parameter
get_global_param.c: (Jenny?) NEW_ARNO_TYPE
    Added parameter for reading Bart's new Arno parameters
get_global_param.c: (LCB) LAKE_WETLAND updates
    Added PRT_LAKE parameter to output lake variables during debugging.
ice_melt.c: (LCB) LAKE_WETLAND updates
    Modified method by which lake coverage fraction and ice height 
    are updated? ** Check with Laura **
initialize_global.c: (LCB) LAKE_WETLAND updates
    Added the initialization of PRT_LAKE to the list of debugging flags.
initialize_global.c: (LCB) BLOWING_SNOW update
    Added initialization of BLOWING_SNOW to the list of global parameters.
initialize_lake.c: (LCB) LAKE_WETLAND updates
    Made improvements to the initialization process for lakes.  
    ** Check with Laura **
initialize_model_state.c: (LCB) LAKE_WETLAND updates
    Modified to initialize lake variables.
initialize_snow.c: (LCB) BLOWING_SNOW update
    Modified to initalize blowing_snow variable.
initialize_soil.c: (LCB) LAKE_WETLAND updates
    Modified to initialize wetland soil moisture.
initialize_veg.c: (LCB) LAKE_WETLAND updates
    Modified to get the maximum number of vegetation types passed to 
it.  This allows the maximum number of vegetation types to include 
the wetland vegetation fraction when the lake model is active.
lakes.eb.c: (LCB) LAKE_WETLAND updates
    Modifications were made to improve handling of snow and ice and to 
make the lake algorithm interact with the wetland algorithm.
latent_heat_from_snow.c: (LCB) BLOWING_SNOW update
    Modified to handle the effects of blowing snow.
make_dist_prcp.c: (LCB) LAKE_WETLAND updates
    Modified to allocate vegetation variables for the wetland 
vegetation class.
make_in_and_outfiles.c: (LCB) OTHER
    Modified to print notification that the output fluxes file will be 
in a binary format.
open_debug.c: (LCB) LAKE_WETLAND updates
Modified to open lake model debugging file.
put_data.c: (LCB) LAKE_WETLAND updates
    Updated output of lake variables to reflect algorithm changes.  
put_data.c: (LCB) BLOWING_SNOW update
    Added output variables for blowing snow algorithm.
read_lakeparam.c: (LCB) LAKE_WETLAND updates
    Modified to reflect updates to the lake and wetland algorithms.
read_soilparam.c: (JA) OTHER
    Modified to convert from Bart's new Arno parameters into the 
    standard parameters (Dsmax, Ds, Ws, and c).
read_vegparam.c: (LCB) BLOWING_SNOW update
    Added code to read in blowing snow parameters.
snow_melt.c: (LCB) BLOWING_SNOW update
    Modified to handle blowing snow.
soil_conduction.c (set_node_parameters): (KAC) OTHER
    Modified to correct differences between calculations to determine 
maximum node moisture and node moisture, so that nodes on the 
boundary between soil layers are computed the same way for both.
soil_conduction.c (distribute_node_moisture_properties): (KAC) OTHER
    Modified to check that node soil moisture is less than or equal 
to maximum node soil moisture, otherwise an error is printed to 
the screen and the model exits.
solve_snow.c: (LCB) BLOWING_SNOW update
    Modified to handle the effects of blowing snow.
surface_fluxes.c: (LCB) BLOWING_SNOW update
    Modified to add the effects of blowing snow.
user_def.h: (KAC) SPATIAL_SNOW
    Added TraceSnow to indicate the minimum depth of new snow required 
to reset the snow surface albedo from the ablation to the 
accumulation curve.
vicNl.c: (LCB) LAKE_WETLAND updates
    Updated storage of lake water for water balance calculations.
vicNl.h: (LCB,KAC,JA)
    Updated to reflect model changes.
vicNl_def.h: (LCB,KAC,JA)
    Updated to reflect model changes.
water_energy_balance.c: (LCB) LAKE_WETLAND updates
    Updated to reflect changes in algorithm structure.
water_under_ice.c: (LCB) LAKE_WETLAND updates
    Updated to reflect changes in algorithm structure.
write_data.c: (LCB) LAKE_WETLAND updates
    Updated output of model for lakes and wetlands algorithm.
    ** No lake variables are output when using LDAS format. **
write_data.c: (KAC) BLOWING_SNOW update
    Added additional sublimation terms to LDAS and standard snow
    output files.

Added:
CalcBlowingSnow.c: (LCB) BLOWING_SNOW update
    Subroutine to compute the effects of blowing snow on snowpack 
sublimation.
wetland_energy.c: (LCB) LAKE_WETLAND updates
    Subroutine computes the surface energy balance for exposed 
wetland vegetation.

From comparison of LatestAdminSource (updated above) and SOURCE_4.0.4beta

CalcAerodynamic.c: (KAC) CANOPY_ENERGY_BALANCE update
    This routine was modified to store wind speed, aerodynamics
resistance, reference height, roughness lengh and displacement
height for three conditions: (1) snow-free, (2) snow-covered and
(3) canopy wind speed.
SnowPackEnergyBalance.c: No Changes Needed
StabilityCorrection.c: (KAC) OTHER
    Moved definition of G (gravity) to vicNl_def.h to provide a 
consistant location for all model constants.
alloc_atmos.c: No Changes Needed
arno_evap.c: No Changes Needed
calc_longwave.c: No Changes Needed
calc_rainonly.c: 
    Why does version 4.0.4 check to see if MAX_SNOW_TEMP <= MIN_RAIN_TEMP,
rather than justt less than as the new version does?  Was this a bug
or personal preference?  ** Check This **
calc_surf_energy_bal.c: (KAC) CANOPY_ENERGY_BALANCE update
    Modified to work with the canopy energy balance updates.
calc_surf_energy_bal.c: (KAC) SPATIAL_FROST update
    Modified to work with the spatial frost updates.
calc_surf_energy_bal.c: (KAC) QUICK_SOLVE update
    Modified determine the minimum number of soil thermal nodes to 
capture the maximum amount of the surface energy flux exchange.
This reduces solution time with frozen soil significantly, but 
increases energy balance errors.
canopy_energy_bal.c: (KAC)
This include changes for spatial snow and frost plus the new
canopy energy balance.  No notes indicate fixes made to v4.0.4
that need to be incorporated.
- converted internal time step accounting to seconds from hours
- added check to further restrict evaporative losses if ice content
  is less than wilting point, otherwise dry soils can evaporate too
  much if ice is present.
check_files:
Added lines for lake file
check_state_file.c: (KAC) STATE_FILE updates
    Modified to work with new binary state file, fixed in version 4.0.4.
close_files:
Added lines for lake file
compress_files.c: No changes made
Modified to nice the backgrounded file compression processes.
dist_prcp.c: (KAC) DIST_PRCP, TREELINE and STATE_FILE updates
This will have to be carefully merged, as there are several fixes
and improvements which should be maintained.  Some of these include 
fixes to the accounting storms, updates for spatial frost and snow,
updates for the state file, updates to account for the treeline.
** This will involve some extra effort, especially since distributed
precipitation variables are now account for in several locations. **
--> DRY_TIME and STILL_STORM are now computed separatly for vegetation
    types, this needs to be incorporated into state file.
frozen_soil.c: (KAC)
Modified so that soil layer ice content is only calculated if the 
frozen soil algorithm is implemented and active in the current grid 
cell.
full_energy.c: (KAC)
Added lake algorithm, and canopy energy balance updates.  Nothing
appears to be needed from v4.0.4.
func_surf_energy_bal.c: (KAC)
updated for spatial snow and frost as well as the canopy energy 
balance.  No important changes in v4.0.4 found.
get_global_param.c: (KAC)
    Nothing new in v4.0.4, all additions are in the admin code.
initialize_atmos.c: (KAC)
    Modified to initialize atmospheric pressues in Pa rather than kPa,
all calculations now use Pa eliminating internal conversions.  Added
treeline calculations. Added output of forcing file statistics (this
is in addition to the output of forcing files which was in v4.0.3).
initialize_global.c: (KAC)
    Added initialization of lake variables, blowing snow variables and
QUICK_SOLVE for frozen soil energy fluxes.
initialize_model_state.c: (KAC)
    Updated for canopy energy balance, new model state file, and lakes 
and wetlands algorithm.
initialize_new_storm.c: (KAC)
    Modified to work with spatial frozen soil.
initialize_snow.c: (KAC)
    Modified to initialize blowing snow and spatial snow algorithm 
    variables.
make_dist_prcp.c: (LCB)
    Modified to include wetland variables in the new structures.
make_dmy.c:
    Only white space changes
make_in_and_outfiles.c: (KAC)
    Lake model file control was added
mtclim42_vic.c: (KAC) 
    Modified to compute all pressures in Pa rather than kPa.
mtclim42_vic.h: (KAC)
    Definition of EPS constant moved to vicNl_def.h
mtclim42_wrapper.c: (KAC)
    Changed calls to vicrerror to calls to nrerror.  Now handles 
pressure in Pa, rather than kPa.
open_state_file.c: (KAC)
    Updated to handle binary state file.
penman.c: (KAC)
    Now handles pressure in Pa, rather than kPa.
prepare_full_energy.c: (KAC)
    modified so that ice content is set to zero unless the frozen soil 
algorithm is implemented and active in the current grid cell. 
put_data.c: (KAC)
    modified to incorporate the effects of treeline calculations, the
lake and wetland algorithm, spatial snow and frost algorithms, and 
the canopy energy balance.
read_atmos_data.c: (KAC)
    v4.0.4 multiplies nrecs by NF to check for a long enough file,
    v.4.1.0 multiples by dt.  I think new version is probably correct.
read_initial_model_state.c: (KAC)
    Updated to handle binary state file.  Need to address storm state
variables!
read_snowband.c: (KAC)
Modified to allocate treeline variable.  Will need to update to fix
    lake model/snow band problem!
read_soilparam.c: (KAC, JA)
    Modified to read in spatial snow and frost parameters and to read in 
Bart's new Arno parameter set.  
read_soilparam_arc.c: (KAC)
    Modified to read in spatial snow and frost parameters and to read in 
Bart's new Arno parameter set.
read_vegparam.c: (DP,KAC)
    Modified code to update Wdmax based on LAI values read in for the 
current grid cell.  If LAI is not obtained from this function, then 
the values cacluated in read_veglib.c are left unchanged.
redistribute_during_storm.c: (KAC)
    Modified to work with distributed snow and frozen soil.
runoff.c: (KAC)
    Modified to handle spatial snow and soil frost.
snow.h: (KAC)
    Added minimum SWQ for computing snow pack energy balance.  Added
    coefficients of shortwave attenuation through the snowpack.  
Removed minimum SWQ for full coverage, now included in the soil 
files.
snow_intercept.c: (KAC)
    Modified to handle new variables required to close the canopy 
energy balance.
snow_melt.c: (KAC)
    Modified to handle partial snow cover.  Modified to assure that 
ground heat flux is used properly in the snow surface energy 
balance as well as imporving the handling of energy fluxes for 
partial snow cover.  Modified to handle blowing snow.
snow_utility.c: (KAC)
    Moved definition of G to vicNl_def.h.
soil_conduction.c: (KAC)
set_node_parameters:
    Modified to correct differences between calculations to determine 
maximum node moisture and node moisture, so that nodes on the 
boundary between soil layers are computed the same way for both.
distribute_node_moisture_propertes:
Modified to check that node soil moisture is less than or equal to 
maximum node soil moisture, otherwise an error is printed to the 
screen and the model exits.
estimate_layer_ice_content:
Modified to find ice content in spatial frost bands.
solve_snow.c: (KAC)
- Added partial snow cover and advection of sensible heat from local 
bare patches.
- Modified to pass the minimum depth of full snow cover as a variable 
in soil_con rather than a globally defined constant.
- Fixed check of new snow accumulation for setting understory flag to 
use snowfall[WET] not snowfall.
- Set MELTING flag to maintain melting albedo curve even during brief 
periods of refreezing, until a snowfall exceeds SnowThres.
- Modified to handle the effects of blowing snow.
- Modified to handle closed canopy energy balance.
surface_fluxes.c: (KAC)
    - Modified to handle partial snow cover.
    - Modified to iterate a solution for the exchange of energy between 
the snowpack and the ground surface.
    - Modified to add the effects of blowing snow.
    - Fixed indexing problem for sub-daily snow model within daily water 
balance VIC: hour (now hidx) is incremented by 1 rather than the 
sub-daily time step, so the atmospheric forcing data is now properly 
indexed.
- Indexing fix sent SNOW_STEP to calc_surf_energy_bal rather than the 
model time step, meaning that without snow the evaporation was 
computed for SNOW_STEP hours rather than a full day.  This was fixed 
by introducing step_inc to index the arrays, while step_dt keeps 
track of the correct time step.
svp.c: (KAC)
    Modified internal calculations to use kPa rather than Pa for 
consistancy
user_def.h: (KAC)
    Added options for lake model, closing the canopy energy balance,
computing the treeline, computing statistics from the input 
forcings, and controls for spatial snow and frost.
vicNl.c: (KAC)
    - Added controls for lake model.
- Updated storage of lake water for water balance calculations.
- Modifed to add AboveTreeLine to soil_con_struct so that the model 
can make use of the computed treeline.
- Modified to initialize storm parameters using the state file.
    - Modified to start the model by skipping records until the state 
file date is found.  This replaces the previous method of modifying 
the global file start date, which can change the interpolation of 
atmospheric forcing data.
- Modified to store wet and dry fractions when intializing water 
balance storage.  This accounts for changes in model state 
initialization, which now stores wet and dry fractions rather than 
just averaged values.
vicNl.h: (KAC)
    Added definitions for treeline and forcing stats subroutines and
made some needed modifications to subroutine definitions due to
other changes, however, other changes still need to be made.
vicNl_def.h: (KAC)
    Modified to handle lake algorithm, blowing snow, spatial snow and
frost, and treeline calculations.
write_data.c: (KAC)
- Made hour a variable in all output data file formats even if the 
model is run at a daily time step.  Also modified all output files 
to account for new variables introduced by the spatial frost and 
snow algorithms, the lake algorithm and the PILPS 2e study.
- Added energy fluxes to snow band output files.
- Updated output of model for lakes and wetlands algorithm.  Added 
output of blowing snow sublimation to LDAS and standard snow output 
files.  ** No Lake Variables are included in the LDAS output format. 
**
- Modified LDAS SWQ output, so that it is multiplied by 10 instead 
of 100 before being converted to a short integer.  This reduces 
stored value precision to 0.1, but increases the maximum storable 
SWQ, which was exceeded in previous LDAS simulations.
    - Eliminated different formats between energy balance and water
balance model output.
write_debug.c: (KAC)
    Modified to work with closed canopy energy balance.
write_forcing_file.c: (KAC)
Modified to output pressures, which are handled internally in kPa, 
as Pa for backward compatability.
write_layer.c: (KAC)
    Modified to handle spatial soil frost.
write_model_state.c: (KAC)
- Rewritten to handle updates to vicNl_def.h and to write the file 
as binary to minimize write time and differences with simulations 
started with the state file.
- Model is now restarted with the correct values for mu and 
LAST_STORM.
    ** Still need to account for differences with distributed 
precipitation flags, which now differ with vegetation - also need
to check storage of lake variables, blowing snow variables and 
MELTING flag.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.1.1

* Description of changes from VIC 4.1.0 beta r5 to VIC 4.1.1 *

New Features:

Modified reporting of aerodynamic resistance in output files.

Files Affected:

full_energy.c
func_canopy_energy_bal.c
func_surf_energy_bal.c
output_list_utils.c
put_data.c
surface_fluxes.c
vicNl_def.h
wetland_energy.c

Description:

Replaced the existing variables aero_resist_used and Ra_used with
arrays of two elements each; [0] corresponds to surface values
(bare soil or non-overstory veg; with snow or snow-free) and [1]
corresponds to overstory or non-overstory veg.  For non-overstory
veg, elements [0] and [1] are the same.

Added the following output variables to store the average aerodynamic
conductance and resistance of the grid cell corresponding to elements
[0] and [1], respectively: OUT_AERO_COND1, OUT_AERO_COND2,
OUT_AERO_RESIST1, and OUT_AERO_RESIST2.  Changed the computation
of OUT_AERO_COND and OUT_AERO_RESIST to be "scene" values, i.e.
veg tiles containing overstory contribute their overstory (element
[1]) values, and non-overstory veg tiles contribute their surface
(element [0]) values.  Earlier versions of VIC simply output the
values of AERO_COND and AERO_RESIST computed latest during the time
step (whether from surface or overstory).

Added AERO_RESIST_CANSNOW option.

Files Affected:

display_current_settings.c
func_canopy_energy_bal.c
get_global_param.c
global.param.sample
initialize_global.c
vicNl_def.h

Description:

This option allows the user to control how aerodynamic resistances
in the overstory are corrected for the presence of snow in the canopy.

Possible values are:
  AR_406: Multiply aerodynamic resistance by 10 for latent heat
      calculation but NOT for sensible heat, and do NOT apply
      stability correction, as in VIC 4.0.6 and earlier.
      Additionally, use surface aero_resist for ET when no
      no snow in canopy.
  AR_406_LS: Multiply aerodynamic resistance by 10 for both latent
      and sensible calculations, but do NOT apply stability
      correction.  Additionally, use surface aero_resist for
      ET when no no snow in canopy.
  AR_406_FULL: Multiply aerodynamic resistance by 10 for both latent
      and sensible calculations, but do NOT apply stability
      correction.  Always use canopy aero_resist for ET.
  AR_410: Apply stability correction but do not multiply by 10, as in
      VIC 4.1.0.  Always use canopy aero_resist for ET.
  AR_COMBO: Apply stability correction and multiply resulting resistance
      by 10.  Always use canopy aero_resist for ET.

VIC 4.1.0 differed from VIC 4.0.6 (and earlier) in the computation
of aerodynamic resistances in snow-filled canopy.  This new option
allows backwards-compatibility with both of these model versions, as
well as the new "AR_406_LS", "406_FULL" and "AR_COMBO" options, for
comparison.  The default is set to AR_410.

Reinstated the COMPUTE_TREELINE option, with option to supply the average July
air temperature.

Files Affected:

compute_treeline.c
display_current_settings.c
get_global_param.c
global.param.sample
initialize_atmos.c
initialize_global.c
read_snowband.c
read_soilparam_arc.c
read_soilparam.c
read_vegparam.c
user_def.h
vicNl.c
vicNl.h
vicNl_def.h

Description:

COMPUTE_TREELINE:

This option revives the treeline elevation computation that is a
current feature of VIC 4.0.x.  If set to TRUE this flag will
force the VIC model to compute the elevation of the tree line,
based on elevation at which the average annual July air temperature
is at or below 10C.  All snowbands above this evelation are then
assumed to be above the treeline, and vegetation types with
overstory are removed from the snow band average variables.  If no
non-overstory vegetation types exist in an above-treeline band,
the band will be treated as if it consists of a default vegetation
type, specified by the user.

To use this option, insert the following line into the global
parameter file:
  COMPUTE_TREELINE  n
where n is the id number of the desired default vegetation type to use
when no non-overstory vegetation types exist in the band.  To specify
bare soil, set n to a negative number.

To deactivate treeline calculation, change the line in the global
parameter file to
  COMPUTE_TREELINE FALSE
or remove the line from the global control file.

WARNING #1: Since the model does not store default root zone
distributions, the default vegetation type will use the
values from the last defined vegetation type for the current
grid cell (i.e. veg type N-1, prior to the addition of the
new vegetation type).

WARNING #2: If you are using GLOBAL_LAI, than the LAI and
dew storage terms for the default vegetation type will be set
to the values used by the last occurrence of the default
vegetation type.

JULY_TAVG_SUPPLIED:

The default behavior of VIC is to compute the average July temperature
from the meteorological input forcings, over the time span of the
simulation.  One drawback to this behavior is that, for short
simulations over different periods of time, the average July
temperature can vary enough to change which elevation bands are
considered to be above the treeline.

Therefore, if desired, the user can specify the average July
temperature for each grid cell by taking the following 2 steps:
  1. Add each grid cell's average July air temperature to the soil
     parameter file, as the final field on each line.
  2. Set JULY_AVGT_SUPPLIED = TRUE in the global parameter file

The JULY_AVG_SUPPLIED option is ignored if COMPUTE_TREELINE is FALSE.

Added OUT_VPD output variable.

Files Affected:

output_list_utils.c
put_data.c
vicNl_def.h
write_forcing_file.c

Description:

Added the output variable OUT_VPD to track vapor pressure deficit.

Added OUT_ASAT output variable.

Files Affected:

full_energy.c
output_list_utils.c
put_data.c
runoff.c
surface_fluxes.c
vicNl_def.h
vicNl.h
wetland_energy.c

Description:

Added the output variable OUT_ASAT to track saturated area.

New MIN_LIQ option, with fixes to min_liq formulation.

Files Affected:

arno_evap.c
display_current_settings.c
frozen_soil.c
get_global_param.c
global.param.sample
initialize_global.c
initialize_model_state.c
initialize_soil.c
lakes.eb.c
runoff.c
soil_conduction.c
vicNl_def.h
vicNl.h

Description:

Made use of min_liq (instead of residual moisture) optional, via
options.MIN_LIQ.  If MIN_LIQ is FALSE (or omitted) in global
parameter file, all equations that depend on liquid soil moisture
use residual moisture as their absolute minimum liquid water
content.  If MIN_LIQ is TRUE, all of these equations use min_liq
as their absolute minimum liquid water content.  Min_liq is
computed in soil_conduction.c as residual moisture multiplied
by the max_unfrozen_water content at the current temperature.

Made min_liq formulation more consistent across the model code.
Added min_liq to the layer_struct so that this temperature-dependent
quantity can be computed once per time step and communicated to all
functions that look at soil moisture.           TJB

New PLAPSE option, which lapses air pressure (and density) by grid cell average elevation.

Files Affected:

display_current_settings.c
global.param.sample
initialize_atmos.c
initialize_global.c
vicNl_def.h

Description:

Previously, when air pressure was not supplied in the input forcings,
VIC would set it equal to a constant 95.5 kPa.  Now, if options.PLAPSE
is TRUE, and if air pressure is not supplied, VIC computes it by
lapsing sea level pressure by grid cell average elevation.  Air
density is handled the same way.            TJB

New GRND_FLUX_TYPE option, with fixes to deltaH and fusion equations.

Files Affected:

display_current_settings.c
func_surf_energy_bal.c
get_global_param.c
global.param.sample
initialize_global.c
surface_fluxes.c
vicNl_def.h

Description:

Corrected deltaH and fusion terms of surface energy balance, by taking
surf_atten into account, as in Liang et al 1999.  Added GRND_FLUX_TYPE
option, to allow backwards compatibility with versions 4.0.6 and
4.1.0.

Possible values are:
  GF_406: use (flawed) formulas for ground flux, deltaH, and fusion
          from VIC 4.0.6 and earlier
  GF_410: use formulas from VIC 4.1.0 (ground flux is correct,
          but deltaH and fusion ignore surf_atten)
  GF_FULL: use correct ground flux formula from VIC 4.1.0 and
          also take surf_atten into account in deltaH and fusion
GF_FULL is the default value.

Added validation of Campbell's expt and bubble pressure.

Files Affected:

read_soilparam.c

Description:

Previously, VIC did not check to see if "nodata" values such as -9999
were supplied in the soil parameter file for the Campbell's expt and
bubble pressure parameters.  These values would produce "nan" in
computations of soil hydraulic conductivity and soil ice content.  This
is especially insidious in the case of bubble pressure, as it is not
needed for the water balance mode, and therefore users often set it to
"nodata" values for water balance mode runs.  Subsequently using such a
soil parameter file for a full-energy balance or frozen soil simulation
would cause the model to crash without the cause being clear.  Now, the
validation in read_soilparam() prevents this case.

Note: read_soilparam_arc() computes these quantities internally and
already validates their values.

Added TFALLBACK option, to continue with previous temperature when energy
balance iteration fails to converge.

Files Affected:

calc_atmos_energy_bal.c
calc_surf_energy_bal.c
dist_prec.c
display_current_settings.c
frozen_soil.c
func_surf_energy_bal.c
get_global_param.c
global.param.sample
ice_melt.c
initialize_global.c
initialize_lake.c
initialize_model_state.c
lakes.eb.c
output_list_utils.c
put_data.c
root_brent.c
snow_intercept.c
snow_melt.c
solve_snow.c
surface_fluxes.c
vicNl_def.h
vicNl.h

Description:

Added options.TFALLBACK, which can take the following values:
  TRUE: If energy balance solution fails to converge, use previous
        T value and continue
  FALSE: If energy balance solution fails to converge, report an
         error
Default = TRUE.

Currently, the following temperature variables are affected by the
TFALLBACK option:
    snow.surf_temp  : snow pack surface temperature
    energy.T[]      : soil T profile nodes
    energy.Tsurf    : surface temperature
    energy.Tcanopy  : temperature of canopy air
    energy.Tfoliage : temperature of canopy snow

    For each grid cell, for each of the above variables, VIC will count
the number of instances when the previous step's T was used.  These
totals will be reported at the end of the grid cell's simulation.

In addition, VIC tracks occurrences of T fallbacks through time via
"flag" variables.  For each T variable, there is a corresponding T
fallback flag, which is set to 1 if, in a given time step, the
previous step's T was used in that time step, and 0 otherwise.  This
holds for each veg tile / elevation band combination in the grid cell.

These time series of occurrences of T fallbacks can be reported in
output files via the following 4 new output variables:
  OUT_SOILT_FLAG = array of flags, one for each soil T node
  OUT_SURFT_FLAG = flag for Tsurf
  OUT_SNOWT_FLAG = flag for snow.surf_temp
  OUT_TCAN_FLAG = flag for Tcanopy
  OUT_TFOL_FLAG = flag for Tfoliage
Each of these contain the AVERAGE over the entire grid cell and over
the output time interval (if aggregating temporally) of the flag
values.  Thus, these are NOT integers but fractions ranging from 0 to
1.

Additionally modified root_brent to continue attempting to bracket
root if one bound encounters undefined values/ERROR code from target
function.

Added computation of 6 types of potential evaporation.

Files Affected:

arno_evap.c
CalcAerodynamic.c
canopy_evap.c
compute_pot_evap.c (new)
full_energy.c
global.h
initialize_lake.c
initialize_model_state.c
lakes.eb.c
Makefile
output_list_utils.c
penman.c
put_data.c
read_soilparam_arc.c
read_soilparam.c
read_veglib.c
read_vegparam.c
surface_fluxes.c
vicNl.c
vicNl_def.h
vicNl.h
wetland_energy.c

Description:

Added computation of potential evaporation for 6 different reference
land cover types, along with new output variables for reporting them:
  OUT_PET_SATSOIL = pot evap from saturated soil
  OUT_PET_H2OSURF = pot evap from open water surface
  OUT_PET_SHORT   = pot evap from short reference crop (clipped grass)
  OUT_PET_TALL    = pot evap from tall reference crop (alfalfa)
  OUT_PET_NATVEG  = pot evap from current vegetation with canopy
            resistance computed in the usual manner except
            for the absence of water limitation
  OUT_PET_VEGNOCR = pot evap from current vegetation with canopy
            resistance set to 0

Four "default" veg library classes were created (defined in global.h)
so that veg characteristics for these landcover types (such as
roughness length, etc) are present regardless of the contents of the
externally-supplied vegetation library.  As a result, bare soil no
longer is treated as an exception within the code, but as a legitimate
class having its own area fraction Cv, etc.  This simplifies some of
the loops in the code.

In order to compute potential evaporation for these different cases,
several different aerodynamic resistances also needed to be computed.
Rather than store all of these in the cell_data structure, the
"aero_resist" array of the cell_data structure was removed and
the previously-named "aero_resist_used" array was renamed to
"aero_resist".  Now, the pre-stability-correction values of
aero_resist are stored in a temporary internal array and not reported.

Finally, computation of canopy resistance was moved out of penman()
and into a separate function calc_rc() within the same file.

Simplified argument lists of runoff() and surface_fluxes().

Files Affected:

full_energy.c
runoff.c
surface_fluxes.c
vicNl.h
wetland_energy.c

Description:

Simplified the argument lists of runoff() and surface_fluxes() by
replacing explicit references to individual cell_data variables by
a single reference to the cell_data structure.

Wetland portion of lake/wetland tile is now simulated in full_energy().

Files Affected:

free_dist_prcp.c
frozen_soil.c
full_energy.c
initialize_lake.c
initialize_model_state.c
initialize_soil.c
LAKE.h
lakes.eb.c
make_dist_prcp.c
Makefile
put_data.c
read_initial_model_state.c
read_lakeparam.c
read_soilparam.c
read_soilparam_arc.c
read_vegparam.c
soil_conduction.c
vicNl.c
vicNl_def.h
vicNl.h
wetland_energy.c (removed)
write_model_state.c

Description:

In previous versions of 4.1.x, the wetland portion of the lake/wetland
tile was stored in the (N+1)st vegetation tile, and processed in the

` function wetland_energy(), which was an almost exact duplicate of
full_energy(). This created several difficulties, including a) potential
conflicts with the COMPUTE_TREELINE option, b) conflicts with the new
implementation of bare soil and potential evap, c) hard-coding of
wetland vegetation to be equal to the grid cell's first listed cover
type, and d) general complexities in maintaining the code/adding new
features.

Now, the wetland portion of the lake/wetland tile must be listed in
the vegetation parameter file in the same was as all other veg cover
types.  Similarly, the wetland portion of the lake/wetland tile is
processed in full_energy() in the exact same way as all other tiles.
Wetland_energy() has been removed.  Lakemain() has also been removed,
as the calls to lake-specific functions are now executed directly from
full_energy().  To make all of this happen, the index of the veg tile
containing the lake/wetland must be indicated in the lake parameter
file (thus, the lake parameter file must contain an additional
value for each grid cell).

Users may now specify any type of desired vegetation to fill the
wetland portion of the lake/wetland tile, simply by listing the
desired veg cover in the veg param file and placing the index of this
tile in the lake parameter file.  The user is also free now to create
a new wetland vegetation class in the vegetation library.

State files now contain data for 0-area bands.

Files Affected:

read_initial_model_state.c
write_model_state.c

Description:

In order to ensure that the value of Nbands saved in the state file
accurately accounted for the number of bands whose states are stored
in the state file, changed VIC to read/write data for all bands,
whether or not their area is 0.

Bug Fixes:

Fixed conflict between PRT_SNOW_BAND option and flexible output configuration.

Files Affected:

global.param.sample
parse_output_info.c
put_data.c
vicNl_def.h

Description:

The PRT_SNOW_BAND option exists for backwards-compatibility with older
versions of VIC.  If the user is using the default output cofiguration,
and PRT_SNOW_BAND is set to TRUE, it creates "snowband" output files.
However, this was not made clear in the documentation; it is possible
to specify output files containing the snow-band-specific values of
variables without setting PRT_SNOW_BAND to TRUE.  However, put_data()
contained logic that only allowed it to record snow-band-specific
quantities if PRT_SNOW_BAND is TRUE, even if the user had specified
snow-band-specific output variables in the output files.

Therefore, the logic checking the value of PRT_SNOW_BAND was removed
from put_data().  Additionally, if the user has specified N_OUTFILES
in the global parameter file, PRT_SNOW_BAND will now be set to FALSE
by parse_output_info(), just to make sure that PRT_SNOW_BAND only
applies to the default output case.  Documentation in
global.param.sample and vicNl_def.h has been updated to reflect this
behavior.                       TJB

Fixed problems in soil temperature solution due to use of dz_node.

Files Affected:

calc_surf_energy_bal.c
frozen_soil.c
func_surf_energy_bal.c
initialize_model_state.c
lakes.eb.c
soil_conduction.c
vicNl.h
wetland_energy.c

Description:

The addition of the EXCESS_ICE option introduced a new variable,
Zsum_node, to the soil thermal solution code.  This conflicted with
the existing variable dz_sum.  Therefore, dz_sum has been replaced
by Zsum_node in several functions.          KAC via TJB

Fixed problem of errors from put_data() not being caught.

Files Affected:

dist_prec.c

Description:

Modified routine to store put_data() error in ErrorFlag2 and
return a single ERROR value if an error occurs.     KAC via TJB

Fixed uninitialized value errors in parse_output_info.c.

Files Affected:

parse_output_info.c

Description:

Added default values for format, typestr, and multstr, so that they
can be omitted from global param file.          TJB

Fixed inability to read tabs in soil/veg parameter files.

Files Affected:

read_soilparam.c
read_vegparam.c

Description:

At some point in earlier versions, the functions that read soil/veg
parameter files were modified to use the "strtok" function, and as a
result, VIC lost the ability to understand tabs as field separators
in these files.  This ability has now been restored.    TJB

Fixed bugs in snow bands implementation.

Files Affected:

output_list_utils.c
read_snowband.c
read_vegparam.c
vicNl.c
vicNl.h
vicNl_def.h

Description:

Some snowband-specific output variables had an incorrect number of
elements allocated in output_list_utils.c.  This has been fixed.  In
addition, added BandElev[] array to soil_con_struct.  Also added logic
to ensure that grid-cell-average elevation (from soil parameter file)
matches the average of the band elevations.  Also added allocation of
extra veg tile for the case of a band being above the treeline in the
COMPUTE_TREELINE case.                  TJB

Removed special logic for longwave in water balance mode

Files Affected:

func_surf_energy_bal.c
intialize_atmos.c
initialize_model_state.c

Description:

In the 4.0.x branch of VIC, net longwave radiation was stored in the
atmos.longwave variable for the case of water balance mode.  This
required that special logic be inserted into various parts of the
code wherever the longwave variable was used.  In 4.1.x, new features
were added and several different types of longwave flux were added.
None of these new fluxes took the water-balance case into account, and
as a result, the water balance case was handled incorrectly.  Now the
special handling of the water balance case has been removed; atmos.longwave
always contains incoming longwave.  This also simplifies the code.
TJB

VIC now can understand indented comment lines in the global parameter file

Files Affected:

get_global_param.c

Description:

Previously, VIC only understood a line to be a comment if it began
with a '#' character at the very beginning of the line, i.e. no
leading white space such as spaces or tabs.  Now, any line whose first
non-whitespace character is '#' is considered to be a comment.

Miscellaneous fixes to snow albedo aging scheme

Files Affected:

initialize_snow.c
SnowPackEnergyBalance.c
snow_melt.c
solve_snow.c

Description:

Previously, VIC's last_snow counter, which keeps track of the number
of time steps since the last fresh snowfall, and which is used to
compute the snow albedo, was not reset to 0 at the proper times.  This
has been fixed, along with its initialization.

Fixed errors in summing output variables

Files Affected:

dist_prec.c
full_energy.c
initialize_lake.c
initialize_model_state.c
initialize_snow.c
LAKE.h
lakes.eb.c
put_data.c
read_initial_model_state.c
read_snowband.c
read_soilparam_arc.c
read_soilparam.c
vicNl.c
vicNl_def.h
vicNl.h
write_model_state.c

Description:

Previously, many lake water and energy budget terms were lumped into
the wetland soil, snow, and energy structures.  This often led to
water/energy balance errors both internally and in summing these terms
for output.  To solve this problem, new cell, snow, and energy
structures were added to the lake_var structure.  These structures
allow all lake water and energy budget terms to be tracked
independently of the wetland.

In addition, previously, the initial computation of water/energy
storages for use in the water/energy balance checks was done in
vicNl().  This logic was not in sync with the computations in put_data().
Therefore the logic was replaced with an initial call to put_data()
(using rec= -Nrecs).  Within put_data(), two new functions were
created to help ensure that summing was consistent among upland veg
tiles, wetland, and lake: collect_wb_terms() and collect_eb_terms().  

Finally, another source of errors arose from the allocation and
initialization of snowband parameters in read_snowband().  These
terms were only initialized in read_snowband(), but were in some cases
used in put_data() for the non-snowband case.  Therefore, we have
moved the allocation/initialization of these terms to read_soilparam()
and read_soilparam_arc().  These parameters are further modified in
read_snowband(), as necessary.

Added error messages for case when LAI==0 and overstory==1.

Files Affected:

read_veglib.c
read_vegparam.c

Description:

Added error messages for case when LAI==0 and overstory==1.  Without
this check, a user could specify LAI of 0 for an overstory type (e.g.
a deciduous tree).  Unforutunately, the model code assumes that the
overstory itself always contains some minimum LAI (perhaps assuming
that the LAI contains stem area as well?), and in some cases divides
by the LAI.  If LAI ever is 0 for an overstory type, this will lead
to nan values in evap, soil moisture, canopy storage, etc.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.0.4

June 4, 2003: VIC release 4.0.4beta r2

This covers bugs found during tests with the snow algorithm.

    solve_snow.c: Bug found by KAC
    Counter for number of days since last snowfall was 
    incremented twice in the MELTING update.  This has been
    fixed.
solve_snow.c: modification by KAC
    Added check so that MELTING flag is only TRUE if melt
    occurs in the melt season - currently this is defined
    between March 1 and October 1.  Otherwise the MELTING
    flag can trigger rapid very early season melt
write_model_state.c, read_initial_model_state.c, open_state_file.c,
check_state_file.c: Modification by KAC
    Modified to handle both ASCII and BINARY state files.
    NOTE: ASCII mode is designed to make it easier to create 
    a state file for initializing a point model.  It includes 
    all features of the Binary state file, but values are 
    truncated so the resulting restart will not be identical.
    If you need an exact restart, use the Binary files.  Also
    removed ice content from the state file as it is computed
    at the beginning of each time step, so storing its value
    is unnecessary.

April 23, 2003: VIC release 4.0.4beta r1

This covers bug fixes found by beta testers and fixed in the version of
the code bundled with this file.

surface_fluxes.c: (found by Ingjerd Haddeland)
    Indexing fix sent SNOW_STEP to calc_surf_energy_bal rather
    than the model time step, meaning that without snow the 
    evaporation was computed for SNOW_STEP hours rather than a
    full day.  This was fixed by introducing step_inc to 
    index the arrays, while step_dt keeps track of the correct
    time step.

March 27, 2003: VIC release 4.0.4beta

This release covers patches for several bugs found in 4.0.3, which were
never formally released (i.e. the downloadable source code was modified,
but no major announcement was made). It also includes other fixes and
modifications that have been identified as being needed prior to releasing
version 4.1.0, which will involve several significant changes (including
lakes & wetlands, spatial snow & frost, and a closed canopy energy balance).

Modifications:

Snow albedo update: (found by Keith)
     In previous releases, the snow albedo function has been hyper 
     sensitive to trace amounts of snowfall during the melt period.  
     Whenever new snow falls or the cold content falls below 0, the 
     albedo is switched from the ablation curve to the accumulation 
     curve.  This curve is then followed until the cold content 
     exceeds 0, indicating it is in the spring melt season.  This is 
     fine when accounting for thin early season snowpacks or mid-
     season melt events, however, a cold snap or light dusting of 
     snow should not reset the snowpack albedo to much higher winter 
     values for days or weeks at a time.  This release of the model 
     monitors the state of pack with the variable MELTING.  This 
     flag keeps the snowpack on the ablation curve unless new snow-
     fall exceeds a threshold (TraceSnow in user_def.h) indicating 
     that the top of the snowpack should be represented by the albedo 
     of the new snow.
Model initialization: (found by Ulysses and Keith)
     In previous releases, the initialization of soil layer moist[] 
     and ice[] was within a second set of loops for band and 
     vegetation, using the same counters.  Because of the dual use
     of counters, initialization was not completed correctly.  The
     primary effect of this was that thermal node values beyond the
     first vegetation type were not correctly initialized, which 
     caused the model to crash during some simulations with full
         energy or frozen soils active.  Without frozen soil, most 
     simulations would compensate for the problem within their
     spin-up time, so it is unlikely that this bug impacts any 
     simulations not employing frozen soil.
Snow time step: (found by Andy, et al.)
     The snow algorithm needs to run sub-daily for the energy balance
     components to function properly.  This means that for daily 
     simulations, the snow model must be solved at a finer (sub-daily)
     time step.  In the previous release, initialize_atmos.c stored
     sub-daily met data in each days variable using positions (e.g. 
         0,1,..8 for 3 hour data).  In surface_fluxes.c the model indexed 
     the sub-daily time steps used by the snow algorithm with hours 
     (e.g. 0,3,6,...21 for three hour data).  This means the arrays
     were incorrectly indexed and the resulting model simulations 
     would be wrong.  The fix implemented here has been tested under 
     several model configurations and is deemed the official version.
     WARNING: There are several versions of this fix circulating,
     please update your code to this version - the previous fixes
     may not work in all circumstances!
FROZEN_SOIL active flag: (found by Ed and Justin)
     The cause of the problem is a bug in the code that occurs when 
     the global frozen soils flag (FROZEN_SOILS) is set to true but 
     the individual cell frozen soil flag (FS_ACTIVE) is set to 
     false. This causes the change in soil heat storage to be 
     calculated incorrectly.  This was fixed by adding additional
     conditions within frozen_soil.c and initialize_model_state.c,
     which verify the FS_ACTIVE is TRUE before running 
     estimate_layer_ice_content.  This avoids the problem of the 
     soil layer ice content being set to a positive value, ignored
     by the rest of the model.
Vapor pressure: (Keith)
     All internal vapor pressure calculations are now done in 
     Pascals.  Previous release versions, switched between Pa
     and kPa, so this simply removes the extra step.  The input
     file format is unchanged, so there should be no change to
     model output (model might run slightly faster, but it is
     also unlikely that this will be witnessed by a normal user).
Constant dew despite changing LAI: (Dave Peterson)
     The modification of read_vegparam.c to update LAI based on 
     a grid cell specific value did not change the values of Wdmax.  
     Wdmax values were computed in read_veglib.c based on the 
     default LAI values, so they did not necessarily reflect the 
     actually LAI values used for the grid cell.  Values for Wdmax 
     are now computed in read_vegparam.c whenever GLOBAL_LAI are 
     provided.  The effects of this change will change in magnitude
     based on how different the cell LAI values are from those in
     the default library file.
DRY_TIME error: (Reinur Schnur)
     DRY_TIME in dist_prcp.c was incremented by the time step in 
     hours.  Then to see if the current rain was part of the same 
     storm or the start of a new one, DRY_TIME was checked to see 
     if it was greater than or equal to 24/dt.  This compares 
     DRY_TIME in hours to the model time step.  The "/dt" has been 
     removed, so now DRY_TIME is checked versus the hours since the 
     last storm.
State file: (KAC)
     *** WARNING: This may require modifications to your global file ***
     The state file has been modified to account for model updates.
     It has also been converted to write binary files - this makes 
     them less convenient to edit, but means that model starts using
     the same forcing, soil and vegetation files will produce the
     exact same results.  There has also been a slight change in how
     the global file is set up to restart the model.  The global
     file should now have the same year, month, day and hour as the 
     original global file - the VIC model will compute the number of
     records to skip at the beginning to reach the point where the 
     model state was saved.  This means that calculations to yield
     sub-daily metrological forcings from daily forcings will produce 
     the exact same forcing values -> this also means that restarted
     simulations will be exactly the same as the original run.  Slight
     variations in the model results were also introduced because the
     method for storing soil node depths led to the possibility of 
     very small differences in dz_node for the restarted model.  
     Previous versions also did not store the snowpack cold content,
     this meant that for restarts during winter, the snowpack albedo
     might start on the ablation curve (as cold content was initialized
     to 0 and not to a value less than 0) rather than the accumulation
     curve.  This could lead to slight differences in the snowpack
     if no new snow fell and the snowpack was not melting - but
     after 10 years of simulations the differences were minor.  As 
     noted above the new version of the state file should allow the
     model to be restarted and to produce exactly the same results as
     the original complete result.  If there are cases where this is
     not true, please report.  If you edit the read/write model state
     functions - BE VERY CAREFUL to edit Nbytes to reflect any changes.
COMPUTE_TREELINE: (KAC and LCB)
     This is an added feature which computes the treeline elevation
     in the current grid cell and does not include vegetation 
     fractions with overstory in the grid cell averages for snow bands
     that exceed the treeline elevation.  This feature was added
     to the model to reduce the appearance of "glaciers" in high
     elevation snow bands.  It computes average annual July air
     temperatures using the temperature data from the atmospheric
     forcing files (WARNING - elevation of treeline may change if
     the period of forcing data used changes).  It then lapses the
     average annual July air temperature to locate the elevation 
     at which it equals 10C.  This is assumed to be the treeline,
     so vegetation types with overstory in snow bands with average 
     elevations higher than this, are excluded from the grid cell
     average variables in put_data.c.  For the time being full 
     energy and water balances are still computed for these 
     vegetation fractions, and no attempt is made to verify that
     a snow band has a non-overstory vegetation type that can be 
     expanded to represent the coverage area lost due to the 
     exclusion of the overstory fraction.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.0.3

August 15, 2000: VIC release 4.0.3

This release fixes a problem with the implementation of va_arg that
causes run time errors on some systems. Previous releases of the code
worked correctly on the LINUX and freeBSD systems where it was tested.
However on some systems (including Sun Ultra-2s) character variables
passed with va_arg are changed into integers so reading a character from
the argument list does not produce the value sent to the routine. The
character flags used by VIC to indicate if there is snow present and if
the frozen soil algorithm has been activated have now been converted to
integers, which should make the va_arg call work on all systems.

Also fixed in this release was a check in dist_prec.c to see if it is
still raining which actually used the memory address of the
precipitation variable rather than the daily value in the check.

MODIFIED FILES:
read_atmos_data.c - Fixed input file time step check
write_forcing_files.c - Added free statements for pointers
calc_surf_energy_bal.c - Converted char flags to int
dist_prec.c - Fixed logical statement error
frozen_soil.c - Converted char flags to int
func_surf_energy_bal.c - Converted char flags to int
initialize_atmos.c - Added flag for output forcing
vicNl.h - Converted char flags to int
vicNl_def.h - Converted char flags to int

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.0.2

July 19, 2000: VIC release 4.0.2

Two new pre-processor options have been added to VIC as well as minor
modifications to two subroutines.

If set to TRUE the NO_REWIND pre-processor option stops the VIC model from
rewinding the soil and vegetation parameter input files for each new grid
cell. This reduces run times but requires that all input files are in the
same order as the soil parameter file.

If set TRUE the OUTPUT_FORCE pre-processor option blocks off the main
model and only reads the provided forcing files. Once VIC has estimated
the missing forcing parameters the full forcing data set for the defined
simulation period is output to a series of gridded forcing files. The
gridded forcing files are written to the RESULTS directory defined in the
global control file with the prefix "full_data_". The new files are in
Binary or ASCII depending on the setting of BINARY_OUTPUT.

The error messages in get_global_param.c have been modified so that the
correct file is referenced when telling the user to change values found in
the model source code.

In read_soilparam.c, the soil parameters are defined only if the current
grid cell is run, otherwise the line in the file is skipped and soil_con
is returned without new data values.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.0.1

May 30, 2000: VIC release 4.0.1

Increased use of the released VIC model code has lead to the
discovery of a couple of minor bugs. This release fixes those bugs as
well as introducing a improved precipitation correction algorithm based on
Yang et al. 1998. Unless you have encountered these problems or are
trying to correct precipitation undercatch due to wind, in the VIC
model, your results will not be impacted by these fixes.

MODIFIED FILES:
correct_precip.c - changed to WMO correction equation for
NWS 8" standard gauge.
full_energy.c - modified to handle WMO correction.
initialize_atmos.c - modified to handle WMO correction.
fixed error in estimating minimum daily
temperature from sub-daily temperatures.
make_in_and_outfiles.c - removed line that opened the state file
again for each new grid cell.
open_state_file.c - modified comments.
put_data.c - modified to handle WMO correction.
snow_utility.c - cleaned source code.
solve_snow.c - modified to handle WMO correction.
surface_fluxes.c - modified to handle WMO correction.
vicNl.h - modified to handle WMO correction.
vicNl_def.h - modified to handle WMO correction.

REFERENCE:

Yang, D., B. E. Goodison, J. R. Metcalfe, V. S. Golubev, R.
Bates, T. Pangburn, and C. L. Hanson, Accuracy of NWS 8" Standard 
Nonrecording Precipitation Gauge: Results and Application of WMO 
Intercomparison, J. Atmos. Oceanic Tech., 15, 54-68, 1998.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

VIC - Release of VIC 4.0.0

Date: May 16, 2000

From: Keith Cherkauer

Topic: Release of VIC 4.0.0

The code for VIC release 4.0.0 has undergone several months of tests (as
VIC release 3.3.0 Beta) and has now been deemed ready for release to the
general public. This document is designed to provide information
concerning changes in the model between the last release version (3.2.1)
and the current version.

There is no formal users manual, information about how to use the current
version can be found at
http://www.hydro.washington.edu/Lettenmaier/Models/VIC/VIChome.html.
Information about the basic model design can be found in Liang, et al.
(1994), while the rewrite of the source code as well as the addition of
cold season processes is described in Cherkauer and Lettenmaier (1999).

The VIC macroscale hydrologic model was developed as a research tool. As
such it is the users responsibility to verify that it is working correctly
when applied to new situations. When using the VIC model reference should
be made to Liang, et al. (1994) and Cherkauer and Lettenmaier (1999) as
well as an acknowledgment that the code was received from the University
of Washington. Other important papers relating to the development of the
VIC model are included on the home page and in the source code.

Possible bugs in the code should be reported to
vicadmin@hydro.washington.edu. ALWAYS CHECK YOUR INPUT FILES! Most
"bugs" are actually caused by trying to run the model with bad parameters
or forcing data. The VIC model will run limited checks to find common
major errors but in most cases it will attempt to run with the bad values.
If after checking all of your input data you still believe you have found
a bug in the model, send an e-mail including the complete output from the
model as well as a description of the problem and the files necessary to
run the model to recreate the code (if files are large please put a
compressed tar file in
ftp://ftp.ce.washington.edu/pub/HYDRO/vicadmin/TEMP). Outdated and
modified versions of the code are the responsibility of the user to debug.
Modifications made to the code, which may improve the general model
performance, may be submitted to vicadmin@hydro.washington.edu for
possible inclusion in future versions of the code.

VIC release 4.0.0 represents a major change to the source code from
version 3.2.1. It is strongly recommended that if you were using version
3.2.1 or earlier versions that you update with a complete copy of the new
code.

Major changes from release version 3.2.1 to 4.0.0:

Radiation Estimation Update: The routines to estimate shortwave and
longwave radiation as well as vapor pressure from daily minimum and
maximum temperature and precipitation have been updated to correspond to
the algorithm described by Thornton and Running (1999). These routines
provide significantly improved radiation estimates especially in regions
outside the continental United States.
Model Core Update: The core of the VIC model was rewritten so that all
modes of the model (water balance, energy balance, etc.) make use of the
same model code. This makes it easier to modify the model and have
modifications apply to sll modes, it also allows the model to run with new
combinations of algorithms (i.e. full energy balance mode with the finite
difference ground heat flux solution).
Soil Moisture Transport Update: The frozen and thawed sub-layers added
to the model for the original frozen soil algorithm have been removed.
This makes the soil drainage routine cleaner and faster. Frozen soils now
estimate full layer ice contents from the ice content at each soil thermal
node. Without being confined by sub-layers, the frozen soil algorithm can
now be applied to regions of permafrost.
Forcing File Control Added: Version 4.0.0 moves controls of the forcing
file format and data types into the global control file. The model can
now handle most ASCII column and short int Binary files without writing
new subroutines and recompiling the source code.
Pre-processor Options Added: There are now more option flags in the
source code headers to control which parts of the model are in fact
compiled. This allows the model functionality to be adjusted without the
addition of computationally intensive conditional switching statements.
Model State File: With the release of version 4.0.0 separate snow and
soil initialization files have been combined into a single model state
file. The state file can be created outside the model for starting
simulations with prescribed initial conditions, or the model state can be
saved by VIC at a specified date. Note that currently there will be small
differences between a full and a warm started simulation because radiation
and vapor pressure are estimated using forcing data from the simulation
period, not from the full dataset included in the forcing file. It also
does not store wet and dry fraction information, when running with
distributed precipitation the model is restarted using average soil
conditions.

References:

Liang, X., D. P. Lettenmaier, E. F. Wood, and S. J. Burges, A simple
hydrologically based model of land surface water and energy fluxes for
GSMs, J. Geophys. Res., 99(D7), 14,415-14,428, 1994.

Cherkauer, K. A., and D. P. Lettenmaier, Hydrologic effects of frozen
soils in the upper Mississippi River basin, J. Geophys. Res., 104(D16),
19,599-19,610, 1999.

Thornton, P.E. and S.W. Running, An improved algorithm for estimating
incident daily solar radiation from measurements of temperature, humidity,
and precipitation, Ag. For. Met., 93, 211-228, 1999.

Hydrosphere - Freshwater and Hydrology - C
Published by jhamman over 11 years ago

Recent Releases of VIC

VIC - VIC 5.1.0

VIC 5.1.0 (December 14, 2021)

Announcements

VIC 5.1.0 rc2 (September 28, 2020)

Bug Fixes:

VIC 5.1.0 rc1

Model enhancement:

Bug Fixes:

VIC - VIC.5.1.0.rc2

VIC - VIC 5.1.0.rc1

VIC - VIC 5.0.1

Bug Fixes:

VIC - VIC.5.0.0

VIC 5.0.0

New Features:

Backwards Incompatible Changes:

Deprecated Features:

Bug Fixes:

VIC - VIC.5.0.0.rc2

Major new features in the VIC 5 series, compared to VIC 4

VIC - VIC.5.0.0.rc1

Major new features in the VIC 5 series, compared to VIC 4

VIC - VIC 4.2.d

Bug Fixes

VIC - VIC 4.2.c

Bug Fixes

VIC - Release of VIC.4.2.b

***** Description of changes between VIC 4.2.a and VIC 4.2.b *****

Bug Fixes:

VIC - Release of VIC.4.2

Description of changes between VIC 4.1.2 and VIC 4.2

New Features:

Bug Fixes:

Miscellaneous:

VIC - Release of VIC.4.2.a

Description of changes between VIC 4.2 and VIC 4.2.a

Bug Fixes:

VIC - Release of VIC.4.1.2.m

***** Description of changes from VIC 4.1.2.l to VIC 4.1.2.m *****

Bug Fixes:

VIC - Release of VIC.4.1.2.l

***** Description of changes from VIC 4.1.2.k to VIC 4.1.2.l *****

Bug Fixes:

VIC - Release of VIC.4.1.2.k

***** Description of changes from VIC 4.1.2.j to VIC 4.1.2.k *****

Bug Fixes:

VIC - Release of VIC.4.1.2.j

***** Description of changes from VIC 4.1.2.i to VIC 4.1.2.j *****

Bug Fixes:

VIC - Release of VIC.4.1.2.i

***** Description of changes from VIC 4.1.2.h to VIC 4.1.2.i *****

Bug Fixes:

VIC - Release of VIC 4.1.2.h

***** Description of changes from VIC 4.1.2.g to VIC 4.1.2.h *****

Bug Fixes:

VIC - Release of VIC 4.1.2.g

***** Description of changes from VIC 4.1.2.f to VIC 4.1.2.g *****

Bug Fixes:

***** Description of changes from VIC 4.1.2.e to VIC 4.1.2.f *****

Bug Fixes:

VIC - Release of VIC 4.1.2.d

***** Description of changes from VIC 4.1.2.c to VIC 4.1.2.d *****

Bug Fixes:

***** Description of changes from VIC 4.1.2.b to VIC 4.1.2.c *****

Bug Fixes:

***** Description of changes from VIC 4.1.2.a to VIC 4.1.2.b *****

Bug Fixes:

VIC - Release of VIC 4.1.2

***** Description of changes from VIC 4.1.2 to VIC 4.1.2.a *****

Bug Fixes:

***** Description of changes from VIC 4.1.1 to VIC 4.1.2 *****

New Features:

Bug Fixes:

VIC - Release of VIC 4.1.0

***** Description of changes from VIC 4.1.0 beta r4 to VIC 4.1.0 beta r5 *****

New Features:

Bug Fixes:

***** Description of changes from VIC 4.1.0 beta r3 to VIC 4.1.0 beta r4 *****

New Features:

* Description of changes between VIC 4.2.a and VIC 4.2.b *

* Description of changes from VIC 4.1.2.l to VIC 4.1.2.m *

* Description of changes from VIC 4.1.2.k to VIC 4.1.2.l *

* Description of changes from VIC 4.1.2.j to VIC 4.1.2.k *

* Description of changes from VIC 4.1.2.i to VIC 4.1.2.j *

* Description of changes from VIC 4.1.2.h to VIC 4.1.2.i *

* Description of changes from VIC 4.1.2.g to VIC 4.1.2.h *

* Description of changes from VIC 4.1.2.f to VIC 4.1.2.g *

* Description of changes from VIC 4.1.2.e to VIC 4.1.2.f *

* Description of changes from VIC 4.1.2.c to VIC 4.1.2.d *

* Description of changes from VIC 4.1.2.b to VIC 4.1.2.c *

* Description of changes from VIC 4.1.2.a to VIC 4.1.2.b *

* Description of changes from VIC 4.1.2 to VIC 4.1.2.a *

* Description of changes from VIC 4.1.1 to VIC 4.1.2 *

* Description of changes from VIC 4.1.0 beta r4 to VIC 4.1.0 beta r5 *

* Description of changes from VIC 4.1.0 beta r3 to VIC 4.1.0 beta r4 *

* Description of changes from VIC 4.1.0 beta r2 to VIC 4.1.0 beta r3 *

* Description of changes from VIC 4.1.0 beta r1 to VIC 4.1.0 beta r2 *

* Description of changes from VIC 4.1.0 beta r5 to VIC 4.1.1 *