Jim, Evan, CF board:
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 <mailto:jim.biard at noaa.gov>
> 828-271-4900
>
>
>
> Follow us onFacebook <https://www.facebook.com/cicsnc>!
>
> On Jul 16, 2013, at 11:59 AM, Evan Manning
> <Evan.M.Manning at jpl.nasa.gov <mailto: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 - 10:57:53 BST
