Jim, We're only half disagreeing. When there is a lake (or ice/snow?) on top of the land, you are talking about the radiative surface at the bottom of the atmosphere, not the top of the dirt. If I understand correctly, you only make a special case for designated oceans.
So a more precise name might be "nonsea_surface_skin_temperature". Then if we have 50/50 land & lake with T=310 and 290: nonsea_surface_skin_temperature=300 sea_surface_skin_temperature=(fill value) But 50/50 land & sea with T=310 and 290: nonsea_surface_skin_temperature=310 sea_surface_skin_temperature=290 Ice on land would presumably be counted as land but sea ice could still be counted as either land or sea with this terminology. so if we have 4 equal portions 1/4 non-ice-covered non-sea (land/lake/vegetation/whatever) T=290 1/4 ice-covered non-sea T=270 1/4 non ice-covered sea T=280 1/4 ice-covered sea T=260 Then either we count sea ice as sea: nonsea_surface_skin_temperature=280 (men of 270 and 290) sea_surface_skin_temperature=270 (mean of 260 and 280) Or sea ice is not sea: nonsea_surface_skin_temperature=273.3 (men of 260, 270 and 290) sea_surface_skin_temperature=280 -- Evan On Tue, Jul 16, 2013 at 9:36 AM, Jim Biard <[email protected]> wrote: > Evan, > > I'm afraid I have to disagree. I'm working with the MODIS and VIIRS Land > Surface Temperature products right now, and they are attempting to report > the temperatures of the soil/rock/plants/water/etc themselves. The sea > surface is masked off, but temperature for water such as lakes and rivers > (and puddles) is reported. The emissivities of the various surface > constituents are used in the algorithms that generate the products. The > top surface of the land is definitely what is of interest. To give one > example, the products are used in drought studies, where they are used to > try and determine how wet the soil is. > > Grace and peace, > > Jim > > Jim Biard > Research Scholar > Cooperative Institute for Climate and Satellites <http://www.cicsnc.org/> > Remote Sensing and Applications Division > National Climatic Data Center <http://www.ncdc.noaa.gov/> > 151 Patton Ave, Asheville, NC 28801-5001 > > [email protected] > 828-271-4900 > > > > Follow us on Facebook <https://www.facebook.com/cicsnc>! > > On Jul 16, 2013, at 11:59 AM, Evan Manning <[email protected]> > wrote: > > The rewording specifies that puddles are "land". What about ponds? > lakes? rivers? great lakes? Oceans? > > What if we have a grid square that is 50% land at 310 K and 50% ocean at > 290 K? > Would it be correct to have these two variables associated with it: > sea_surface_skin_temperature=290 > land_surface_skin_temperature=310 (i.e. T of only the non-sea portion) > or: > sea_surface_skin_temperature=290 > land_surface_skin_temperature=300 (i.e. mean T of land & sea portions) > > How does that change if instead of being 50% ocean it is 50% lakes & > rivers? > Or lots and lots of puddles? > > I think what we're interested in is not so much the top surface of the > land as the > lower boundary of the atmosphere. So I like "surface_skin_temperature", > which > could then be used with a dimension for surface categories. > > -- Evan > > About a month ago, I submitted a new standard name for the > "land_surface_skin_temperature." While I think the consensus is now that > this new name seems acceptable for inclusion in the CF database, there were > some comments and suggestions by various people who pointed out that the > proposed definition for this quantity could use some more clarification and > other comments which pointed out similarities to the current name > "surface_temperature." I've attempted to address both of these concerns by > adding another line to the definition which better defines what the > "land_surface_skin" is. My hope is that this clears up some uncertainty > about this quantity (e.g. it is not simply the bare land surface but also > includes various media above the land surface) and also illustrates that it > is not the same thing as the "surface_temperature" quantity (which I > understand as idealized, infinitesimally thin interface temperature between > the air and land/sea and not the observable quantity that the > "land_surface_skin_temperature" proposes to be). > > With this is mind, here is my latest attempt at this new name/definition: > > Standard Name: land_surface_skin_temperature > > > > Definition: The land surface skin temperature is the aggregate > temperature of the “land surface skin,” which is the portion of the land > surface which emits infrared radiation directly to space through the > atmosphere. The “land surface skin” is defined as an effective layer which > includes the upper boundary of the land combined with additional layers > which may cover the upper land boundary (e.g. vegetation, puddles, snow, > ice, man-made objects). > > > > Canonical Units: K > > > Sincerely, > > Jonathan > > On 6/20/2013 7:56 AM, Jonathan Gregory wrote: > > Dear Karl > > Like Roy, I don't think we should deprecate sea_surface_skin_temperature. > Although I cannot remember the arguments - which must be apparent in the > mailing list archive - I do recall that it was a careful and long > discussion > with Craig which led to the introduction of the various SST names. > > Therefore adding land_surface_skin_temperature seems fine to me if there is > a need to be precise about this as an observable quantity, which relates > to a particular layer, even though it's very thin. The definition should > note > that if this precise meaning is not intended, the name surface_temperature > could be used, which strictly refers to the temperature at the interface. > > Best wishes > > Jonathan > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > >
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