[CF-metadata] CMIP6 Sea Ice MIP: Ice thickness

From: martin.juckes at stfc.ac.uk <martin.juckes>
Date: Tue, 2 Aug 2016 08:26:09 +0000

Dear Jonathan, Dirk, Alison,

It looks as though you have resolved all the issues nicely, but I have one concern about Jonathan's suggestion for dealing with the thickness of ice floating in melt ponds on the surface of sea ice. The suggestion is to use the existing standard name "floating_ice_thickness" with a cell methods term of the form "area: mean where sea_ice_melt_pond". My concern is that there is some ambiguity here between the thickness of the ice floating in the melt pond and the thickness of the sea ice underneath the melt pond, which is floating in the sea. This might be resolved if "floating_ice_thickness" was to be defined in such a way as to exclude sea ice, but the current definition does not do this. (It states that '"Floating ice" means any ice that is floating on water, e.g. on a sea or lake surface.')

I have a 2nd comment about the suggested area type of snow_covered_sea_ice: this has been proposed for use with variables which represent the amount of snow on sea ice (m) and the heat content of that snow (J m-2). In both cases these are quantities which can be considered as zero on snow-free sea ice, in which case there is no need to mask them by the area of snow cover (I believe Jonathan has advanced this argument in another thread recently). In this case, amount of snow on sea ice would just be represented by "surface_snow_thickness" with cell methods "area: mean where sea_ice over all_area_types" (or "area: mean where sea_ice over sea").

regards,
Martin
Received on Tue Aug 02 2016 - 02:26:09 BST