"Land surface skin temperature" and "sea surface skin temperature" are
commonly used for MODIS/VIIRS, "surface skin temperature" is commonly used
for AIRS.
I think MODIS/VIIRS have separate groups of people handling "land" and
"sea". "Land" is the domain of the the land science group and "sea" is the
domain of the sea science group. But for CF we want to make geophysical
distinctions, and land/sea is not a clear red line. Problem areas include
inland water, tidal river mouths, and frozen surfaces.
If we provide a "surface skin temperature" with the option to use an
additional dimension for surface types, then this supports the AIRS
approach with no additional dimension; it supports the MODIS approach with
an additional dimension of size 2 (land/sea); it also supports others who
might want to break out frozen surfaces or group all liquid water in a
single category.
-- Evan
Yes, this is also the case for the future GOES-R data product that is
> motivating this new standard name. It will report the land surface
> temperature for all non-ocean surfaces. So, for instance, lakes and rivers
> that are internal to land will have land surface temperatures reported.
> The GOES-R sea surface temperature data product, on the other hand, only
> reports temperatures for the sea/ocean surface.
>
> The purpose of my submission of "land_surface_skin_temperature" is to add
> the commonly used quantity, land surface temperature (sometimes also
> referred to as land surface skin temperature) to the CF database. Just as
> the sea surface skin temperature is used by the SST community for the
> temperature of the sea or ocean, the land surface (skin) temperature is the
> quantity that refers to the temperature of all land surfaces (which may or
> may not be covered by other things - lakes, rivers, snow, vegetation,
> buildings, etc.). I think this delineation motivates two standard names,
> the already existing sea_surface_skin_temperature, and a new one to cover
> the land surface (skin) temperature. My view is that the science community
> already commonly uses these two quantities and has for a long time, so the
> CF database should as well.
>
> If this approach is taken, then I do agree with Evan that specifically
> where the sea and land intersect, that some portion of the data point will
> be land and some will be ocean (this depends on the resolution of the data,
> of course). My guess for this scenario is that each dataset has some
> unique way to determine if the data point is "land" or "sea." However, the
> GOES-R surface temperature products do not report the fraction of land/sea
> for data points where land/sea intersect - they simply report a temperature
> as either "sea" or "land" based on their way of identifying the pixel as
> "land" or "sea."
>
> Sincerely,
>
> Jonathan
>
> On 7/16/2013 12:36 PM, Jim Biard 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
>
> jim.biard at noaa.gov
> 828-271-4900
>
>
>
> Follow us on Facebook <https://www.facebook.com/cicsnc>!
>
> On Jul 16, 2013, at 11:59 AM, Evan Manning <Evan.M.Manning at jpl.nasa.gov>
> 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
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Received on Tue Jul 16 2013 - 11:19:28 BST
