Dear Dirk I believe that this distinction can be recorded by the existing mechanisms of "where" and "over" in cell_methods, using the existing standard_name of sea_ice_thickness. Please see Section 7.3.3 of the CF standard. The grid-box- mean sea-ice thickness is "area: mean where all_area_types" and the thickness meaned over sea-ice only is "area: mean where sea_ice", I think.
Best wishes Jonathan ----- Forwarded message from Dirk Notz <[email protected]> ----- > Date: Tue, 19 Jul 2016 09:53:02 +0200 > From: Dirk Notz <[email protected]> > To: [email protected] > Subject: [CF-metadata] CMIP6 Sea Ice MIP: Ice thickness > User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 > Thunderbird/38.8.0 > > Dear CF community, > > traditionally, the variable sea_ice_thickness from CMIP-type model > output was calculated by dividing the entire volume of sea ice in a grid > cell by the entire area of the grid cell, independent of the area > fraction of the grid cell that was actually covered by sea ice. > > This gave rise to substantial confusion for users who expected that > sea_ice_thickness as stored within CMIP simulations refers to the actual > sea-ice thickness that is used in the sea-ice model code to calculate > heat fluxes, for example, rather than the average ice thickness that the > ice would have if it were to cover the entire area of the grid cell > while conserving its volume. > > To prevent such confusion in the future, we would like to add the > following variable to the CF convention: > > 1. equivalent_sea_ice_thickness (new variable with units 'm3 m-2' or 'm') > to describe sea-ice volume per grid-cell area > > The term "Equivalent sea-ice thickness" is known within the sea-ice > community to refer to "sea-ice volume per grid-cell area". Ideally, we > would have liked to suggest a variable name containing the term > "volume", but this seems difficult within the CF convention as then > units couldn't be 'm'. > > Thank you very much for any feedback, help and guidance. > > Best, > > Dirk Notz > > > > -- > ---- > Dr. Dirk Notz > http://www.mpimet.mpg.de/~notz.dirk > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
