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NCAR / DART

Data Assimilation Research Testbed
https://dart.ucar.edu/
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Feature request: ...add a new DART quality flag for output in obs_seq.final #675

Closed prabshr closed 3 weeks ago

prabshr commented 2 months ago

Use case

Need to add a new DART quality flag for output in obs_seq.final

Is your feature request related to a problem?

If the geolocation of observation is outside the cutoff radius specified in "input.nml" for the grids in model domain, DART prints out Quality Flag of "0" although the increments are zero and there is no difference between prior and posterior ensemble. This was observed for a point scale model run.

Describe your preferred solution

Maybe a new Quality Flag to tell users that the observation is outside the influence area for the model domain?

Describe any alternatives you have considered

The user will need to understand what is happening.

hkershaw-brown commented 2 months ago

Hi @prabshr,

Just so we're on the same page about what you're requesting. Here's a sketch of a model domain which is a square with 9 grid points.

Do you mean the case where the cutoff (circle) is smaller than the grid spacing:

Or the observation being outside the grid? If the observation is outside the model grid, then the forward operator should fail, which would give a qc=4. If you're in this situation and getting qc=0 then this might be a bug in the model_mod code.

hkershaw-brown commented 3 weeks ago

closing for now, will reopen if we get more info.