Feature: MSE metrics inside/outside regional domain for stretched grid models (KNMI)

[jswijnands]

Description of functionality Four new metrics have been added for stretched grid models. The first two metrics compute the weighted MSE (i) only inside the regional domain and (ii) only outside the regional domain. The former will allow for comparison of LAM and stretched grid models in the future. Further, two additional metrics have been added that compute the contributions of these components to the overall weighted MSE. This enables monitoring which of the two is the main driver of the training process, as it indicates whether we are mainly optimising the loss inside or outside the regional domain.

Configuration options Both features can be turned on or off in the config options by specifying the following stretched grid metrics (sg_metrics) in the diagnostics config:

• wmse_per_region (True/False)
• wmse_contributions (True/False)

Outputs Plots of these metrics are generated in MLFlow, specified as ‘wmse_inside_lam_epoch’, ‘wmse_outside_lam_epoch’, ‘wmse_inside_lam_contribution_epoch’, and ‘wmse_outside_lam_contribution_epoch’.

Further comments

• Note that this PR is dependent on a PR that provides the stretched_grid.yaml graph config.
• This PR has also been tested together with the PR on custom domain weighting, to check that these features interact as expected.
• A CERRA config has been added for testing purposes, but does not have to be merged into anemoi.

[FussyDuck]

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:white_check_mark: jswijnands
:white_check_mark: havardhhaugen
:white_check_mark: Sooph-knmi
:x: Sophie Buurman

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