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.
2008/4/30 Pamment, JA (Alison) <J.A.Pamment at rl.ac.uk>:
> Dear Craig, Jonathan and all contributors to this thread,
>
>
>
> I have changed the subject line back to the original, just to underline
> that there is a separation between the more fundamental discussion of 'what
> standard names are for' and the specific set of proposals for SST names.
>
>
>
> It seems that we now have agreement on the following names:
>
> surface_temperature
> sea_water_temperature (for temperatures at depth)
> sea_surface_skin_temperature
> sea_surface_subskin_temperature
> sea_surface_foundation_temperature
>
>
>
> The first two are already in the standard name table. The remaining three
> will be added to the table at the next update on 13th May 2008.
>
>
>
> The definition of surface_temperature will be modified very slightly to
> remove the parenthesised word "(skin)". The three new names will closely
> follow the GHRSST definitions at
> https://www.ghrsst-pp.org/SST-Definitions.html. Craig, can you please
> confirm that you are happy with the wording of the following:
>
>
>
> 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" means 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 millimeters 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.**
>
>
> sea_surface_foundation_temperature:
>
> *The surface called "surface" means the lower boundary of the atmosphere.
> *The sea surface foundation temperature is the temperature of the water
> column free of diurnal temperature variability (daytime warming or nocturnal
> cooling) and is considered equivalent to the quantity with standard name
> sea_surface_subskin_temperature in the absence of any diurnal signal. It is
> named to indicate that it is the foundation 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
> profile in the surface layer), that is, sea surface foundation temperature
> is measured at the base of the diurnal thermocline. Only in situ contact
> thermometry is able to measure sea surface foundation temperature and
> analysis procedures must be used to estimate the its 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 (SST) considered representative
> of the oceanic mixed layer temperature and represented by any sea
> temperature measurement within the upper ocean over a depth range of 1 to
> approximately 20 meters. The "bulk" SST has the standard name
> sea_surface_temperature. For the temperature of sea water at a particular
> depth or layer, a data variable of sea_water_temperature with a vertical
> coordinate axis should be used. Sea surface foundation temperature
> provides a more precise, well-defined quantity than "bulk" SST and,
> consequently, is more representative of the mixed layer temperature. 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, but some differences could exist. Note that this quantity does not
> imply a constant depth mixed layer, but rather a surface layer of variable
> depth depending on the balance between stratification and turbulent energy
> and is expected to change slowly over the course of a day.
>
>
>
> Best wishes,
>
> Alison
>
>
>
> ------
>
> 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.
>
--
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
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