Area average time series

[mo-tomosevans]

Include area average time series plots capability.
Addresses #1910.

Contribution checklist

Aim to have all relevant checks ticked off before merging. See the developer's guide for more detail.

• Documentation has been updated to reflect change.
• New code has tests, and affected old tests have been updated.
• All tests and CI checks pass.
• Ensured the pull request title is descriptive.
• Ensure rose-suite.conf.example has been updated if new diagnostic added.
• Conda lock files have been updated if dependencies have changed.
• Attributed any Generative AI, such as GitHub Copilot, used in this PR.
• Marked the PR as ready to review.

[github-actions]

[mo-tomosevans]

The image attached was generated for air temperature, having used the AREA_AVG method. This is for one cycle, not yet introduced a method/recipe for running over multiple data file inputs.

[mo-tomosevans]

Having difficulty introducing existing aggregation methods to create aggregated area average plots.
When file path is pointing to operational UKV data at <path>/*.pp, ensure_aggregatable_cube does not produce an aggregated cube and fails, outputting

ValueError: ("Cube should have 'forecast_period' and 'forecast_reference_time' dimension coordinates."

I tried the pre-existing generic_surface_domain_mean_time_series_case_aggregation_*.yaml recipes with the same data and they all produced the above error, so I think it may be part of a wider issue for how the archived ukv data is loaded in read_cubes.

[James Frost (jfrost-mo)]

Having the aggregation be done area weighted for spatial collapses would be a nice enhancement. However, I wonder if you would always want it. In a team discussion earlier today we couldn't think of any cases where you wouldn't want this, so I'm tempted to make it happen for MEANs and SUMs without having to specify the special AREA_AVG method, conditional on the collapse being over two spatial coordinates. This would then be more easily usable, as we would default to doing the right thing.

Does that sounds like a sensible idea?

[mo-tomosevans]

That still covers what the RES generates with its area average plots so happy to go ahead with that approach.