Difficulties running inference with AIFS v1.1

AIFS, IFS and OpenIFS
1

Hello everyone,

I’m trying to run inference with AIFS v1.1, following the approach in run_AIFS_v1.1.ipynb. I’ve tested two different setups:

  • Running a forecast based on IFS data with minimal modifications to the notebook.

  • Adapting the code to read ERA5 data (converted into the required AIFS input format) and performing hindcast inference on historical data.

In both cases, the inference diverges quickly from the initial conditions and evolves toward an unphysical atmospheric state. Below, I’ve included examples showing this behavior for temperature and the U component of wind in the forecast inference for a lead time of 3 days. For the hindcast experiments based on ERA5, I also compared the results against ERA5 itself, finding very large discrepancies.

Has anyone experienced a similar issue, or could suggest possible causes for this divergence?

Any insights or advice would be greatly appreciated.

Thanks in advance!