Dear all,

O.K. I withdraw my suggestion to deprecate sea_surface_skin_temperature.

I do think the definitions should say how skin temperature differs from surface temperature. Maybe someone can explain that in a few words.

As I understand it, temperature is only defined when molecules are involved. So surface_temperature I think should be defined as the temperature of the surface molecules on the ocean or land/vegetated surface. I don't think there are any useful observational measurements of this temperature either in the ocean or land. Models do calculate these a surface temperature, and as I understand it models use this as their surface radiating temperature so in that sense the temperature is identical to skin_temperature, I would think.

It sounds to me like in land observations, at least, the skin_temperature is not precisely defined because the effective radiating layer depends presumably on what wavelengths are being sensed. To precisely say what the temperature represents one would have to show what fraction of the radiation originated from different depths. saying 10-20 microns of course gives an idea about this, but it isn't precise.

Also, the definition of land_surface_skin_temperature should clearly indicate (when it represents an area mean) whether it is meant to be the area mean of the soil or of the "solid or liquid surface" as seen from above which might include vegetation, puddles, etc. [as an aside, I wonder if the thickness of the layer producing the radiation varies much from one material to the next.]

It does seem a shame to me that users looking for surface_temperature information will now have to search both for surface_temperature and surface_skin_temperature, but I'll accede to the clear majority that thinks both are necessary.

best regards,
Karl

On 6/20/13 4:56 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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