New sub-section and standard names for land surface variables

[SamanthaPullen]

This PR addresses Issue #59

This PR adds some variable names to the CCPP Standard Names for land surface variables, in preparation for Met
Office work on land surface DA with JEDI. I think it makes sense to add a new sub-section for these surface variables. I have added a subsection land_surface, but it could be a wider scope sub-section covering all surface (i.e. land, sea, sea-ice). Please advise :)

I have added the following land surface variable names, in alphabetical order (which would be nice to see elsewhere in the CCPP Standard Names list, for ease of reference):

1. land_ice_area_fraction
2. mass_content_of_water_in_top_soil_layer
3. surface_snow_density
4. urban_area_fraction
5. volume_fraction_of_liquid_water_in_soil_at_critical_point
6. volume_fraction_of_liquid_water_in_soil_at_saturation
7. volume_fraction_of_liquid_water_in_soil_at_wilting_point

I have used CF Standard Names (cfconventions.org) where possible, and where nothing suitable exists I have based the proposed CCPP name on the CCPP or CF name of a related or similar variable.

Opened as a draft PR for now to allow coordination between Met Office and JCSDA before submitting for review. Comments welcome in the meantime!

[BenjaminRuston]

thanks @SamanthaPullen ,,,, I'm not part of this repository but @svahl991 wanted to make sure the JCSDA OBS team was also aware.

should tag @ClaraDraper-NOAA as well but may need to send her this link in an email

[SamanthaPullen]

These additions have been discussed with @ClaraDraper-NOAA and she has confirmed that she is happy with them.

[ClaraDraper-NOAA]

These additions have been discussed with @ClaraDraper-NOAA and she has confirmed that she is happy with them.

My apologies, I responded only to the email. These names are fine by me. Thanks for getting this ready @SamanthaPullen

[nusbaume]

Looks good, but I did have one concern that should probably be discussed more widely amongst the group, or at least among folks who know more about land surface modeling than me.

[nusbaume]

My one concern has been resolved. Thanks!

[SamanthaPullen]

There is some associated discussion on the naming conventions and precise definitions of variables for area fractions in #57. This could have implications for the variable names land_ice_area_fraction and urban_area_fraction in this PR

[SamanthaPullen]

I have switched this PR to draft given the related discussion in #57. Will update names for land_ice_area_fraction and urban_area_fraction by appending _of_cell_area after the Easter Holiday and re-open for review

[SamanthaPullen]

@mkavulich @ss421 @svahl991 Following discussion at #57 and for consistency with the naming convention for sea ice fraction variables proposed there, I have modified the following land surface variable names:

• land_ice_area_fraction
• urban_area_fraction

modified to:

• land_ice_area_fraction_of_cell_area
• urban_area_fraction_of_cell_area

Now ready for review again - @nusbaume are you happy with this update?

[MayeulDestouches]

Thanks @SamanthaPullen for this addition. I approve these new names.

[nusbaume]

@SamanthaPullen Thanks for double-checking with me! Yes those changes look fine on my end, so my approval still holds.

[SamanthaPullen]

@nusbaume , @mkavulich, could this PR be merged please? It has had 2 approvals, but strangely only 1 of them is showing in the panel below

[climbfuji]

@SamanthaPullen I'll ping folks directly to make sure this PR gets reviewed promptly. Sorry for the delay.

[climbfuji]

I am in favor of adding these new names. It would be good if @mkavulich and/or @grantfirl also reviewed the PR.

[mkavulich]

@SamanthaPullen thank you for making the discussed changes, sorry for the delay. Merging now.

[SamanthaPullen]

@mkavulich thank you:)

[grantfirl]

Late to the party, but looks fine to me.