Ai2 Climate Emulator (ACE) Workshop

Overview

Join us for a 2-day workshop on the Ai2 Climate Emulator (ACE). ACE is a fast, accurate, state-of-the-art open-source AI emulator of weather and climate trained on observational reanalysis such as ERA5 or physics-based climate models. The workshop will be led by Andre Perkins, who is visiting us from the Allen Institute for AI (Ai2).

With this workshop, we want to bring together people using climate model emulators or want to explore their use in their research, to share experiences and foster exchange. Whether you are a seasoned climate modeler, a student eager to learn about new tools, or just curious about the potential of AI in atmospheric science, this workshop is for you. You will learn about the capabilities and limitations of ACE, get hands-on experience running ACE for your own research questions, and have the opportunity to connect with other researchers interested in using ACE.

ACE is a family of models designed to simulate atmospheric variability from the time scale of hours to centuries. ACE is a data-driven weather & climate model that is stable on climatic timescales. Depending on the application, multiple versions exist:

• ACE & ACE2 are autoregressive, atmosphere-only models that capture subseasonal to decadal atmospheric variability and forced responses. ACE & ACE2 have been trained on ERA5 reanalysis and different atmospheric climate models.
• SamudrACE is a coupled atmosphere-ocean emulator trained on GFDL's CM4. It couples ACE2 with the 3D Samudra ocean model to simulate Earth system interactions, including emergent phenomena like ENSO.
• ACE2-SOM couples ACE2 trained on GFDL's SHiELD to a slab ocean model and is trained on climate states with different CO₂ concentrations.
• HiRO-ACE uses a two-stage framework with a stochastic version of ACE (ACE2S) and diffusion-based downscaling to generate 3km-scale fields from coarse global inputs. It is trained on X-SHiELD, a global storm-resolving model.

Goal of the workshop

The workshop will include an introduction on ACE by Andre Perkins and presentations on recent research with ACE, but the main focus will be on practical applications of ACE: hands-on sessions where participants will have the opportunity to run ACE and its components on their own laptops (alone or in groups). We will provide potential applications to experiment with ACE, but encourage participants to bring their own ideas and questions. This includes, but is not limited to:

• Large ensembles: creating large ensembles of the historical climate using ACE2-ERA5 to study variability and forced responses on time scales from subseasonal to decadal.
• Idealized SST experiments: changing the boundary conditions of ACE to test the response to different SST perturbations.
• Multiscale dynamics: techniques for both global-scale circulation and regional downscaling with HiRO-ACE for localized impacts.
• Coupled dynamics: using SamudrACE to study coupled phenomena like ENSO.

Schedule & practical information

Please bring your own laptop on both days. Cloud computing resources will be made available to all participants. We encourage participants to experiment with ACE on their own research questions, but we will also provide example applications to get you started.

Day 1 (May 14): Introduction & ACE applications

Day 2 (May 15): ACE in the wild

All sessions will be held in person at CIRA Commons, Colorado State University. Lunch & coffee will be provided for registered participants.