Dear Craig,
Thanks for your reply. I too am very pleased that agreement has been reached.
I think your descriptions of sea_surface_skin_temperature and sea_surface_subskin_temperature are fine and can go into the table without further modification.
The explanation of sea_surface_foundation_temperature is necessarily rather more complex than those of the other quantities (in fact, I think it has the longest description of any name in the table!). Many thanks for reviewing it with the GHRSST team. I agree that your version is clearer and has a more logical ordering of the information, which first establishes the definition of the physical quantity before discussing measurement techniques and relationships to other SST quantities. In the following I have suggested two or three further modifications, which I hope you agree are small and aimed at enhancing clarity and readability, rather than substantively altering the content.
sea_surface_foundation_temperature
The surface called "surface" is defined as the lower boundary of the atmosphere. The sea surface foundation temperature is the water temperature that is not influenced by a thermally stratified layer of diurnal temperature variability (either by daytime warming or nocturnal cooling). The foundation temperature is named to indicate that it is the temperature from which the growth of the diurnal thermocline develops each day, noting that on some occasions with a deep mixed layer there is no clear foundation temperature in the surface layer. In general, sea surface foundation temperature will be similar to a night time minimum or pre-dawn value at depths of between approximately 1 and 5 meters. In the absence of any diurnal signal, the foundation temperature is considered equivalent to the quantity with standard name sea_surface_subskin_temperature. The sea surface foundation temperature defines a level in the upper water column that varies in depth, space, and time depending on the local balance between therma
l stratification and turbulent energy and is expected to change slowly over the course of a day. If possible, a data variable with the standard name sea_surface_foundation_temperature should be used with a scalar vertical coordinate variable to specify the depth of the foundation level.
Sea surface foundation temperature is measured at the base of the diurnal thermocline or as close to the water surface as possible in the absence of thermal stratification. Only in situ contact thermometry is able to measure the sea surface foundation temperature. Analysis procedures must be used to estimate sea surface foundation temperature value from radiometric satellite measurements of the quantities with standard names sea_surface_skin_temperature and sea_surface_subskin_temperature. Sea surface foundation temperature provides a connection with the historical concept of a "bulk" sea surface temperature considered representative of the oceanic mixed layer temperature that is typically represented by any sea temperature measurement within the upper ocean over a depth range of 1 to approximately 20 meters. The general term, "bulk" sea surface temperature, has the standard name sea_surface_temperature with no associated vertical coordinate axis. Sea surface foundation temperature provides a more precise,
well-defined quantity than "bulk" sea surface temperature and, consequently, is more representative of the mixed layer temperature. The temperature of sea water at a particular depth (other than the foundation level) should be reported using the standard name sea_water_temperature and, wherever possible, supplying a vertical coordinate axis or scalar coordinate variable.
Best wishes,
Alison
> Hello Alison and everyone:
>
> There are several GHRSST-PP science Team members and Oceanographers
> with me at the WMO CLIMAR-III Conference in Poland this week and we
> have reviewed the descriptive text you have prepared for the SST
> standard names.? We agree with the standard names. We agree with the
> definitions you have but propose a revised text which we believe is a
> little clearer.? I hope that you find this aceptable and thank you for
> all your effort and support over the last 10 months or so.? I am
> extremely pleased that we have reached a conclusion and we will finally
> enter the CF namespace
>
> Take care
> Craig
>
> Standard names:
> surface_temperature
> sea_water_temperature (for temperatures at depth)
> sea_surface_skin_temperature
> sea_surface_subskin_temperature
> sea_surface_foundation_temperature
> ?Description for standard names
> sea_surface_skin_temperature:
> The surface called "surface" defines the lower boundary of the
> atmosphere. The sea surface skin temperature is the temperature
> measured by an infrared radiometer typically operating at wavelengths
> in the range 3.7 - 12 micrometers. It represents the temperature within
> the conductive diffusion-dominated sub-layer at a depth of
> approximately 10 - 20 micrometers below the air-sea interface.
> Measurements of this quantity are subject to a large potential diurnal
> cycle including cool skin layer effects (especially at night under
> clear skies and low wind speed conditions) and warm layer effects in
> the daytime.
>
> sea_surface_subskin_temperature:
> The surface called "surface" defines the lower boundary of the
> atmosphere.? The sea surface subskin temperature is the temperature at
> the base of the conductive laminar sub-layer of the ocean surface, that
> is, at a depth of approximately 1 - 1.5 millimetres below the air-sea
> interface. For practical purposes, this quantity can be well
> approximated to the measurement of surface temperature by a microwave
> radiometer operating in the 6 - 11 gigahertz frequency range, but the
> relationship is neither direct nor invariant to changing physical
> conditions or to the specific geometry of the microwave measurements.
> Measurements of this quantity are subject to a large potential diurnal
> cycle due to thermal stratification of the upper ocean layer in low
> wind speed high solar irradiance conditions..
>
> sea_surface_foundation_temperature:
> The surface called "surface" is defined as the lower boundary of the
> atmosphere. The sea surface foundation temperature is the water
> temperature that is not influenced by a thermally stratified layer of
> diurnal temperature variability (either by daytime warming or nocturnal
> cooling). The foundation temperature is named to indicate that it is
> the temperature from which the growth of the diurnal thermocline
> develops each day, noting that on some occasions with a deep mixed
> layer there is no clear foundation temperature in the surface layer. In
> general, sea surface foundation temperature will be similar to a night
> time minimum or pre-dawn value at depths of between approximately 1 and
> 5 meters. In the absence of any diurnal signal, the foundation
> temperature is considered equivalent to the quantity with standard name
> sea_surface_subskin_temperature. The sea surface foundation temperature
> defines a level in the upper water column that varies in depth, space,
> and time depending on the local balance between thermal stratification
> and turbulent energy and is expected to change slowly over the course
> of a day. If possible, sea_surface_foundation_temperature should use a
> data variable with a vertical coordinate axis to specify the depth of
> the foundation level.
> Sea surface foundation temperature is measured at the base of the
> diurnal thermocline or as close to the water surface as possible in the
> absence of thermal stratification. Only in situ contact thermometry is
> able to measure the sea surface foundation temperature (reporting the
> temperature of sea water at a particular depth using the standard name
> sea_water_temperature and when possible including a data variable with
> a vertical coordinate axis). Analysis procedures must be used to
> estimate sea surface foundation temperature value from radiometric
> satellite measurements of the quantities with standard names
> sea_surface_skin_temperature and sea_surface_subskin_temperature.? Sea
> surface foundation temperature provides a connection with the
> historical concept of a "bulk" sea surface temperature considered
> representative of the oceanic mixed layer temperature that is typically
> represented by any sea temperature measurement within the upper ocean
> over a depth range of 1 to approximately 20 meters. The general term
> "bulk" SST is linked to the standard name sea_surface_temperature
> without a vertical coordinate axis. Sea surface foundation temperature
> provides a more precise, well-defined quantity than "bulk" SST and,
> consequently, is more representative of the mixed layer temperature.
>
> --
> Dr Craig Donlon
> Director of the International GODAE SST Pilot Project Office
> Met Office Hadley Centre,
> Fitzroy Road, Exeter, EX1 3PB United Kingdom
>
> Tel: +44 (0)1392 886622 Mob:07920 235750
> Fax:+44 (0)1392 885681
> Skype ID:crazit
> SkypeIn: +44 0141 416 0882
> E-mail: craig.donlon at gmail.com
> http://www.ghrsst-pp.org
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Fax: +44 1235 446314
Rutherford Appleton Laboratory Email: J.A.Pamment at rl.ac.uk
Chilton, Didcot, OX11 0QX, U.K.
Received on Fri May 09 2008 - 07:06:05 BST
