Dear Jonathan,
I agree that the 0C isotherm does not exist everywhere, but it is still a different variable to the one requested. You could try to persuade LS3MIP to use the variable you are describing, but I'm not yet convinced that we can't provide a means of describing the variable they want. You are defining a variable X representing an isotherm which may lie below frozen soil or below thawed soil. They want a variable Y which only represents the isotherm below thawed soil. Y is a masked version of X -- but to describe that masking in CF we would need a new area type to indicate areas for which the surface soil temperature is above zero. regards, Martin ________________________________ From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of Jonathan Gregory <jonathan.greg...@ncas.ac.uk> Sent: 18 May 2018 08:47 To: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] Standard names for LS3MIP: 8 temporal changes + 1 feature depth Dear Martin I agree that the quantity doesn't exist everywhere, but that's the same if you give it a name of its own rather than the more general name of depth. I suggest that specifying the coordinate as soil_temperature specifically implies that it must be non-existent where 0degC is above ground or there is no ground. The value to be given in that case needs a convention, though not necessarily as part of the standard name definition; it could be a CMIP6 convention. It's like the non-existent thickness of sea ice in ice-free sea or land areas. Best wishes Jonathan ----- Forwarded message from Martin Juckes - UKRI STFC <martin.juc...@stfc.ac.uk> ----- > Date: Thu, 17 May 2018 17:26:58 +0000 > From: Martin Juckes - UKRI STFC <martin.juc...@stfc.ac.uk> > To: Jonathan Gregory <j.m.greg...@reading.ac.uk>, "cf-metadata@cgd.ucar.edu" > <cf-metadata@cgd.ucar.edu> > Subject: Re: [CF-metadata] Standard names for LS3MIP: 8 temporal changes + 1 > feature depth > > Dear Jonathan, > > > Yes, it should be 0C, not 0K. > > > I don't think the approach you suggest will work because what we need is the > depth of the first 0C isotherm assuming surface temperature above 0C. We > don't want the depth of the 0C isotherm in regions where the surface > temperature is < 0C. I can't see any way to include these conditions in > existing CF attributes, can you? > > > regards, > > Martin > > > > ________________________________ > From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of Jonathan > Gregory <j.m.greg...@reading.ac.uk> > Sent: 17 May 2018 17:30 > To: cf-metadata@cgd.ucar.edu > Subject: [CF-metadata] Standard names for LS3MIP: 8 temporal changes + 1 > feature depth > > Dear Martin > > All the change_over_time ones look fine to me, thanks. > > > 2.1 dmlt Depth to soil thaw [m] (CliC) > > Depth from surface to the zero degree isotherm. Above this isotherm T > 0o, > > and below this line T < 0o. > > > > When the surface temperature is above 0K and there is frozen soil at some > > point beneath the surface, thawed_soil_depth is the distance from the > > surface to the first 0K isotherm. When there is no thawed soil layer, the > > parameter should be reported as missing. > > > > + Proposed: thawed_soil_depth > > Could we use the standard_name of depth for this, with a coordinate > variable of soil_temperature=0degC? > (I think 0degC is intended above, not absolute zero) > > Best wishes > > Jonathan > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
