Standard names: Surface Temperature where snow or sea ice

[abiardeau]

Date 31/10/2025

Hello, I'm Aurore BIARDEAU from the Copernicus Marine service, and I would like to propose the addition of a new alias for the standard_name surface_temperature :

• Term : surface_temperature_where_snow_or_sea_ice

This variable represents the skin temperature of surfaces exclusively covered by snow or sea ice.

Thanks for your your help

[github-actions]

Thank you for your proposal. These terms will be added to the cfeditor (http://cfeditor.ceda.ac.uk/proposals/1) shortly. Your proposal will then be reviewed and commented on by the community and Standard Names moderator.

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[taylor13]

I think that instead of defining such a standard name, we should consider defining additional "area types". In this case, we would need "snow_or_sea_ice". I know if CMIP, there is a case where it would have been useful to have defined "snow_on_sea_ice" for use in cell_methods "where snow_on_sea_ice". Of course, we can imagine this approach could greatly expand the number of area types.

[abiardeau]

Hello @taylor13 , thanks for your answer.
From what I understand, you recommend to keep using the surface_temperature standard_name alone, but adding the snow_or_sea_ice area type somewhere else in the attributes ?
Thanks, Aurore

[taylor13]

Yes, that's the suggestion, but this would be a decision with potentially broad implications. Would we expand area types to include all x-type_or_y-type options? what about x-type_or_y-type_or_z-type area types? And the aforementioned "snow_on_sea_ice? Hopefully others will express opinions, concerns, or perhaps recommend we exclude such logical expressions and just include the information in the standard_name.

[JonathanGregory]

I think a new area_type of snow_or_sea_ice would be fine. I presume that would include areas with snow on sea ice too—is that right? Unless we get large numbers of combinations proposed, I think we can expand the vocabulary by adding combinations for which there's a use case.

We might think about whether the conjunction should be or or and, though. We already have a few combinations, and they're not consistent:

lake_ice_or_sea_ice
ice_and_snow_on_land
lake_and_inland_sea
primary_and_secondary_land

I'm pretty sure that and and or mean the same thing in these. It depends on whether you read it as "area where A or B is present" or "area where A is present and area where B is present".

[davidhassell]

Jonathan's approach sounds good to me (and his analysis of and and or).

The alternative of changing the conventions to allow multiple types in the cell methods string (or in an area_type coordinate) is no doubt possible, but I don't think is worth it for a small number of cases. If we did go down this route, then we'd have to live with two different ways of encoding "lake_ice or sea_ice", but that's a what-if that shouldn't worry us now.

Cheers,
David

[github-actions]

This issue has had no activity in the last 3 weeks. Accordingly:

• If you proposed this issue or have contributed to the
  discussion, please reply to any outstanding concerns.
• If there has been little or no discussion, please comment
  on this issue, to assist with reaching a decision.
• If the proposal seems to have come to a consensus, please
  wait for the moderators to take the next steps towards
  acceptance.

Standard name moderators are also reminded to review @feggleton @japamment

[JonathanGregory]

In the list of existing "combined" area types that I gave above, more have and than or as a conjunction. Nonetheless, I tend to think that or is less liable to misunderstanding. Hence I prefer snow_or_sea_ice (consistent with that we've already said) for the new area type which Aurore @abiardeau needs.I feel that where snow_and_sea_ice could be taken to mean that both must be present. I think this problem applies also to the existing ice_and_snow_on_land, which means where there is ice on land or where there is snow on land. It doesn't mean where there is snow-covered ice on land, but it could be interpreted like that. Since lake_ice/sea_ice and primary_land/secondary_land are mutually exclusive pairs, the misinterpretation would not arise. Nonetheless, consistency is generally a good thing, to avoid concerns about what differences might imply.

Therefore I propose that we:

• Add snow_or_sea_ice to the area type table, as needed for this issue.

• Replace _and_ with _or_ in the existing area types ice_and_snow_on_land, lake_and_inland_sea, primary_and_secondary_land.

Best wishes

Jonathan