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Recent Releases of ACE

ACE - 2026.5.1

Note that for PyPI versioning consistency reasons this release includes and supersedes the 2026.5.0 release.

What's Changed

Fine-Tuning & Checkpoint Resume

New config options make it easier to resume or fine-tune from existing checkpoints:

  • OptimizationConfig.resume_optimizer_ckpt_path: restore optimizer state when fine-tuning (#1043)
  • EMAConfig.resume_ema_ckpt_path: resume from an EMA checkpoint (#1118)
  • CheckpointStepperConfig: load stepper config directly from a checkpoint (#1103)
  • Optimizer/EMA state is now included in epoch checkpoints (ckpt_{epoch:04d}.tar) (#1104)

Ensemble Inference

  • Initial ensemble (IC ensemble) support added to the evaluator and inference aggregators (#709)

New Models & Architecture

  • filter_preserves_global_mean option added to SFNO (#1100)
  • SecondaryModuleStepConfig / SecondaryModuleStep: compose a secondary module during training steps (#1073)

Coupled Model

  • Stochastic CoupledStepper training (#750)
  • Randomly sampled LossContributions.n_steps (#869)
  • optimize_last_step_only added to coupled LossContributionsConfig (#868)

Diagnostics

  • Power spectrum diagnostics logged in the inference entrypoint (#1078, #1079)
  • Weather eval entrypoint replaced with a more general additional_inference list (#1096)

Data Processing

  • Time subsetting can now be configured prior to time coarsening (#1055)
  • PRMSL added to X-SHiELD data processing configurations (#1036)

Bug Fixes

  • Clamped SSR calculation that was producing NaNs silently dropped from W&B (#1088)
  • Worked around xarray StringDType serialization error (#1086)
  • Signal handler now exits with a nonzero code (#1068)
  • IceCorrectorConfig correctly registered in CorrectorSelector registry (#1044)

Breaking Changes

  • TrainStepperConfig.train_n_forward_steps renamed to TrainStepperConfig.n_forward_steps — all train YAML configs must update this field (#1052)
  • TrainConfig.n_forward_steps removed (was deprecated; use stepper_training.n_forward_steps) (#1052)
  • TrainConfig.weather_evaluation: WeatherEvaluationConfig | None replaced by TrainConfig.additional_inference: list[AdditionalInferenceConfig] (#1096)
  • Sub-aggregator record_batch(time, data) interface replaced by record_batch(data: InferenceBatchData) (#1097)
  • StepLoss.forward() now returns LossOutput instead of torch.Tensor; call .total() for the scalar (#1020)
  • fme.diffusion package removed (#1084)

Full Changelog: https://github.com/ai2cm/ace/compare/v2026.4.0...v2026.5.1

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by brianhenn 20 days ago

ACE - v2026.5.0

What's Changed

New Contributors

Full Changelog: https://github.com/ai2cm/ace/compare/v2026.4.0...v2026.5.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by jpdunc23 27 days ago

ACE - HiRO-ACE Release

This release is the official milestone for our team's change to fully open development, and includes the latest updates for our HiRO-ACE as described in our paper. HiRO-ACE is a two-stage emulation framework for generating 3 km resolution precipitation outputs using a stochastic climate emulator (ACE2S) to generate 100km climate simulations and a downscaling model (HiRO) to generate 3 km precipitation outputs.

See the docs for a quickstart on installation and use, and our huggingface repo for the models and some sample data to run on.

Open Development

Previously, the ACE repo solely held updates related to papers and releases, while most of the development happened behind the scenes in a separate repository. This made it harder for external collaborators to contribute and for users to track development progress. We hope the changeover to all of our development happening here brings us closer to users, facilitating easier paths for soliciting feedback, issues, and development from outside of our group.

Updates

Full Changelog: https://github.com/ai2cm/ace/compare/v2026.1.0...v2026.1.1

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by frodre about 2 months ago

ACE - v2026.4.0

Release date: April 9, 2026
Full Changelog: https://github.com/ai2cm/ace/compare/v2026.1.1...v2026.4.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by elynnwu about 2 months ago

ACE - v2026.1.0

Release marking the switch to open development for the ai2cm team.

What's Changed

Full Changelog: https://github.com/ai2cm/ace/commits/v2026.1.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by frodre 4 months ago

ACE - 2025.11.0

Release date: November 7, 2025
Full Changelog: https://github.com/ai2cm/ace/compare/2025.10.0...2025.11.0

What's Changed

We updated the versions of fme dependencies torch-harmonics (0.7.4 --> 0.8.0) and imageio(<2.27.0 --> >2.28.1) based on user feedback.

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by brianhenn 7 months ago

ACE - 2025.10.0

Release date: October 16, 2025
Full Changelog: https://github.com/ai2cm/ace/compare/2025.7.0...2025.10.0

What's Changed

This release includes the capability to run coupled models (such as those emulating the atmosphere, ocean, and sea ice!) via entrypoints in fme.coupled. We have provided documentation for running inference using coupled model weights.

The deprecated legacy training configuration format (SingleModuleStepperConfig) has been removed in this release. However, breaking changes have been avoided and backwards compatibility has been maintained with existing saved models for most cases.

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by brianhenn 8 months ago

ACE - 2025.7.0

What's Changed

This release includes major internal refactors and improved documentation. The previous training configuration format has been deprecated and will be removed in a future release. However, breaking changes have been avoided and backwards compatibility has been maintained with existing saved models for most cases.

Version updates:

  • Python 3.11 and torch 2.7.1

Internal refactors:

  • The fme package has been moved one level up (i.e., away from the legacy fme/fme/... layout and to fme/ace/ and fme/core/ instead).

Increased modularity for ML emulation:

  • Training configuration is now based around a more flexible StepperConfig; the legacy SingleModuleStepperConfig is deprecated and will be removed in a future release.
  • The stepper config now supports the modular step framework allowing composible steps for ML emulation.

Documentation

  • Added an improved quickstart.rst focused around the models saved in our Hugging Face collection.

Full Changelog: https://github.com/ai2cm/ace/compare/2024.12.0...2025.7.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by brianhenn 11 months ago

ACE - 2024.12.0

What's Changed

This release contains many internal changes for ACE code. However, all configuration options accessible by the entrypoints of the fme package (i.e. fme.ace.train, fme.ace.inference and fme.ace.evaluator) have had no breaking changes.

The following lists are not complete but just a highlight of changes which may be relevant to users.

Bug fixes:

  • resolved transient bug that sometimes occurred in XarrayDataset when trying to read the image shape from a scalar field
  • when using n_repeats greater than 1, XarrayDataset now correctly increments the values in the returned time arrays

New features:

  • ACE works on Apple Silicon! Set the environmental variable FME_USE_MPS=1 to use the pytorch MPS backend. Make sure to have the latest version of pytorch installed. This gives about a 5x speed up over running on CPU (tested on a Macbook Pro M3 Max).
  • add perturbations to sea surface temperature during inference (see ForcingDataLoaderConfig.perturbations)

Refactors:

  • deduplicated some inference code by using generics. Now the fme.ace.inference and fme.ace.evaluator entrypoints now share more code.

Full Changelog: https://github.com/ai2cm/ace/compare/2024.9.0...2024.12.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by oliverwm1 over 1 year ago

ACE - 2024.9.0

What's Changed

New Contributors

Full Changelog: https://github.com/ai2cm/ace/compare/2023.12.0...2024.9.0

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by oliverwm1 over 1 year ago

ACE - 2023.12.0

Inference code for model described in https://arxiv.org/abs/2310.02074

Atmosphere - Atmospheric Composition and Dynamics - Python
Published by oliverwm1 over 2 years ago