Proposer's name Martin Schupfner
Date 2026-05-28
- Term sea_or_inland_water_ice_surface_temperature
- Description The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. "Sea or inland water ice surface temperature" is the temperature that exists at the interface of sea ice or inland water ice and an overlying medium which may be air or snow. In areas of snow covered sea ice or inland water ice, sea_or_inland_water_ice_surface_temperature is not the same as the quantity with standard name surface_temperature. "Sea or inland water ice" means all ice floating in the sea or in inland water bodies which has formed from freezing water, rather than by other processes such as calving of land ice to form icebergs. It is strongly recommended that a variable with this standard name should have a units_metadata attribute, with one of the values "on-scale" or "difference", whichever is appropriate for the data, because it is essential to know whether the temperature is on-scale (meaning relative to the origin of the scale indicated by the units) or refers to temperature differences (implying that the origin of the temperature scale is irrelevant), in order to convert the units correctly (cf. https://cfconventions.org/cf-conventions/cf-conventions.html#temperature-units).
(marked in bold: all differences between this description and the following description of sea_ice_surface_temperature)
- Units K
The description is derived from the existing standard_name sea_ice_surface_temperature (there is a small typo):
The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. "Sea ice surface temperature" is the temperature that exists at the interface of sea ice and an overlying medium which may be air or snow. In areas of snow covered sea ice, sea_ice_surface_temperature is not the same as the quantity with standard name surface_temperature. "Sea ice" means all ice floating in the sea which has formed from freezing sea water, rather than by other processes such as calving of land ice to form icebergs. It is strongly recommended that a variable with this standard name should have a units_metadata attribute, with one of the values "on-scale" or "difference", whichever is appropriate for the data, because it is essential to know whether the temperature is on-scale (meaning relative to the origin of the scale indicated by the units) or refers to temperature differences (implying that the origin of the temperature scale is irrevelant), in order to convert the units correctly (cf. https://cfconventions.org/cf-conventions/cf-conventions.html#temperature-units).
I suggest this standard_name following a comment in issue #25: #25 (comment)
The CF committee discussed this issue at its meeting today (8th September 2025). We agreed on what we would like to arrange, but not how to implement it. To be clear about what we agreed, I propose the following statement:
For any quantity that is defined in a similar way for both sea water and inland water (lakes, rivers, etc.), and for which there's a use case in one or both contexts, we will define three standard names of the form [A_]W[_B], where A and B are the same in all three names, while W can be sea_or_inland_water, sea_water or inland_water. For the purposes of comparing datasets, the three standard names will be regarded as alternatives for the same physical quantity, just as if two of them were aliases of the third. However, unlike with aliases, they will all be equally acceptable, and none of them is deprecated.
This means that for most existing names containing sea_water, we will define two equivalent names e.g. corresponding to sea_water_density we will define inland_water_density and sea_or_inland_water_density. In this example, there is no A phrase, and B is density. We won't do this blindly, since there may be some cases where it doesn't make sense, or where other words have to be changed as well to fit e.g. sea_floor. In future, when a new standard name is agreed for any quantity referring to sea_or_inland_water, sea_water or inland_water, we will define the other two as well, if they make sense.
Since all the ten committee members present at the meeting agreed to this idea, I propose that it will be accepted in three weeks from now (on 29th September) if there are no objections to the above statement. If this statement doesn't seem right to you, please comment and we'll stop the countdown, and likewise if anyone else has concerns.
We did not agree how to implement the above. The simplest way would be to use aliases, but we really want to distinguish the idea of deprecation, implied by aliases, from this new purpose of defining alternative, equivalent, synonymous names. We would like to do it in a way which involves no, or minimal, change to software used to read and to maintain the standard name table, and its correspondence with the NVS. This will require further discussion.
Consistent with the above, I suggest we should add inland_water and sea_or_inland_water to the area_type table. Referring to areas, sea_or_inland_water is the union of sea and inland_water, just as sea is the union of sea_ice and ice_free_sea. The phrases where sea and where inland_water could be used in cell_methods to distinguish the values for a sea_or_inland_water property over the relevant portions of the grid cell.
Proposer's name Martin Schupfner
Date 2026-05-28
- Term
sea_or_inland_water_ice_surface_temperature- Description The surface temperature is the (skin) temperature at the interface, not the bulk temperature of the medium above or below. "Sea or inland water ice surface temperature" is the temperature that exists at the interface of sea ice or inland water ice and an overlying medium which may be air or snow. In areas of snow covered sea ice or inland water ice, sea_or_inland_water_ice_surface_temperature is not the same as the quantity with standard name surface_temperature. "Sea or inland water ice" means all ice floating in the sea or in inland water bodies which has formed from freezing water, rather than by other processes such as calving of land ice to form icebergs. It is strongly recommended that a variable with this standard name should have a units_metadata attribute, with one of the values "on-scale" or "difference", whichever is appropriate for the data, because it is essential to know whether the temperature is on-scale (meaning relative to the origin of the scale indicated by the units) or refers to temperature differences (implying that the origin of the temperature scale is irrelevant), in order to convert the units correctly (cf. https://cfconventions.org/cf-conventions/cf-conventions.html#temperature-units).
(marked in bold: all differences between this description and the following description of
sea_ice_surface_temperature)- Units
KThe description is derived from the existing standard_name
sea_ice_surface_temperature(there is a small typo):I suggest this standard_name following a comment in issue #25: #25 (comment)