Copernicus SST L3S Observation Converter

[mgharamti]

Description:

A new observation converter for a blended satellite Sea Surface Temperature product from the Copernicus Marine Environment Monitoring Service. The converter reads CMEMS NetCDF files and generates DART obs_seq files containing bias-corrected blended SST observations (in K) suitable for assimilation into ocean models such as ROMS. The PR also adds a readme file containing brief documentation for the new converter.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Documentation changes needed?

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

Tests

I've tested the converter with several CMEMS observation files. These can be found here: /glade/work/gharamti/inacawo/data_snippets/SST

Checklist for merging

• Add cmems_sst_to_obs to .gitignore

• Updated changelog entry

• Documentation updated

• Update conf.py

Checklist for release

• Merge into main
• Create release from the main branch with appropriate tag
• Delete feature-branch

Testing Datasets

• Dataset needed for testing available upon request
• Dataset download instructions included
• No dataset needed

[hkershaw-brown]

Hi Moha,

Looking good.

Definite changes:

• call check_namelist_read to catch invalid namelist entries
• readme.rst add the info about the temp being in C in the obs seq to the docs
• add this new converter to the list of available converters in the docs.

Then a few suggestions:
There's a couple of typos that I spotted.
A couple of your loops are looping in the slow order. I am not sure if you want to keep this order to have the obs in a certain order in obs_seq.
Defaults matching in the docs/example input.nml and the code

Cheers,
Helen

[hkershaw-brown]

Same comment on loop ordering, typically you want the inner loop to be the fastest varying.

Note I'm not sure if the observation sequence order is better for science reasons to loop along latitude first.

[hkershaw-brown]

Trying to use type for observation (I know kind is all over the place).

Suggested change

	``SATELLITE_BLENDED_SST`` observation kind.
	``SATELLITE_BLENDED_SST`` observation type.

[hkershaw-brown]

This is a nitpick, but from the docs it seems like you can change the specified threshold, whereas it is a hardcoded parameter.

integer, parameter :: OBS_QC_LOW_QUALITY = 3

Suggested change

	Only observations with quality level greater than a specified threshold
	(default: > 3) are retained.
	Only observations with quality level greater than 3 are retained.

[hkershaw-brown]

Also @todo add cmems_sst_to_obs executable to .gitignore

[mgharamti]

Helen, thanks for the helpful comments. I believe I addressed all of them.

[hkershaw-brown]

Approved!