Thanks Roy, Karl, and Jonathan -
I guess I was hoping for confirmation that one or both terms
(air_pressure_at_sea_level and surface_air_pressure) would be
analogous to sea_surface_temperature, which is defined as
being *near the surface*. In the case of SST, a depth coordinate
is allowed, as far as I can tell from the standard name table.
It looks like surface_temperature would be used without a
depth coordinate, based on the definition below, and I'm
not exactly sure about sea_surface_skin_temperature, which
includes a depth (10 - 20 micrometers) in its definition.
For in situ data, it's preferable to record the measured barometric
pressure and provide a sensor height, rather than correct to sea
level, because the correction algorithm is inexact and because
sensor height can be fully described using attributes - important
on a surface buoy, where the waterline may not be perfectly known.
We could use the standard name air_pressure, but some systems, like
SeaDataNet, distinguish between pressures used as Z coordinate variables
(for balloon or sonde measurements) and pressures that are 'science
observables'. This is a valid distinction, and I'd like to maintain it -
although
that may not be part of the CF approach.
*Sea surface temperature* is usually abbreviated as "SST". It is the
temperature of sea water near the surface (including the part under
sea-ice, if any), and not the skin temperature, whose standard name
is 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.
*surface_temperature* The surface called "surface" means the lower
boundary of the atmosphere. The surface temperature is the
temperature at the interface, not the bulk temperature of the medium
above or below.
Thanks for your input on this -
Nan
On 3/15/12 2:27 PM, Jonathan Gregory wrote:
Dear Nan
If the quantity has "surface" in its standard name, it should not have a
z-coordinate, because "surface" quantities are defined as being values on
"the surface" (i.e. bottom of the atmosphere) z(x,y). Given x and y, z
is known. The same applies to quantities with standard names that contain
other named surfaces, such as toa (rather a vague surface!) or sea_floor.
Best wishes
Jonathan
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