ACE2 demo notebook on JASMIN (PET)

ACE2 is an ML climate model developed by the Allen AI institute, with models and code available from hugging face. They also have ACE-hiro, a diffusion downscaler. We could create a notebook which runs ACE2 for climate and then does some downscaling

- [paper](https://www.nature.com/articles/s41612-025-01090-0)
- [ace2-era5](model https://huggingface.co/allenai/ACE2-ERA5)
- [ace2-hiro](diffusion downscaler https://huggingface.co/allenai/HiRO-ACE)

- [ ] Get model weights
- [ ] Get sample input data (ERA5?, CMIP6?)
- [ ] totrial notebook on ACE2
- [ ] tutorial notebook on ACE-hiro
- [ ] joint tutorial
- [ ] find way to run ACE2 for future climate? downscale CMIP6 future climate stuff

Start by reading the linked paper and the ACE2-ERA5 and HiRO-ACE model pages, then determine how to obtain model weights and sample ERA5 or CMIP6 input data. The work is complete when reproducible notebooks cover ACE2, ACE-hiro downscaling, their joint use, and the proposed future-climate workflow.

Written by the indexing model from the issue text.