| 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 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
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