Hi all -
Sorry if this has been discussed already, but I have an issue with
the term 'height_above_sea_level', defined as "Height_above_X" means
the vertical distance above the named surface X. "sea_level" means *mean*
sea level, which is close to the geoid in sea areas.'
Someone recording observed met data on a buoy, looking for the best term
for the sensor heights, might easily choose this instead of 'height',
but the
height in that case is above actual sea level; varying over time.
If this variable is meant to be 'height above mean sea level', that should
be its name.
Thanks - Nan
On 5/18/17 7:37 AM, [email protected] wrote:
Dear Jonathan, All,
CF trac ticket #143 (https://cf-trac.llnl.gov/trac/ticket/143) has been agreed
and will be included in CF 1.7. A number of new standard names are needed to
support the implementation of this ticket. They are names for constants used in
the formula_terms attribute of parameterized vertical coordinates.
The following names are proposed.
air_pressure_at_top_of_atmosphere_model (Pa)
' "Top of atmosphere model" means the upper boundary of the top layer of an
atmosphere model.'
altitude_at_top_of_atmosphere_model (m)
'Altitude is the (geometric) height above the geoid, which is the reference geopotential
surface. The geoid is similar to mean sea level. "Top of atmosphere model"
means the upper boundary of the top layer of an atmosphere model.'
reference_air_pressure_for_atmosphere_vertical_coordinate (Pa)
'For models using a dimensionless vertical coordinate, for example, sigma, hybrid
sigma-pressure or eta, the values of the vertical coordinate at the model levels are
calculated relative to a reference level. "Reference air pressure" is the air
pressure at the model reference level. It is a model-dependent constant."
height_above_geopotential_datum_at_top_of_atmosphere_model (m)
' "Height_above_X" means the vertical distance above the named surface X. The "geopotential
datum" is the geopotential reference level (level of zero geopotential) where this is not a specifically
named level such as the geoid or a reference ellipsoid. "Top of atmosphere model" means the upper
boundary of the top layer of an atmosphere model.'
height_above_geopotential_datum (m)
'"Height_above_X" means the vertical distance above the named surface X. The
"geopotential datum" is the geopotential reference level (level of zero geopotential)
where this is not a specifically named level such as the geoid or a reference ellipsoid.'
surface_height_above_geopotential_datum (m)
' "Height_above_X" means the vertical distance above the named surface X. The surface called
"surface" means the lower boundary of the atmosphere. The "geopotential datum" is the
geopotential reference level (level of zero geopotential) where this is not a specifically named level such
as the geoid or a reference ellipsoid.'
sea_surface_height_above_geopotential_datum (m)
' "Height_above_X" means the vertical distance above the named surface X. The "geopotential
datum" is the geopotential reference level (level of zero geopotential) where this is not a specifically
named level such as the geoid or a reference ellipsoid. "Sea surface height" is a time-varying
quantity.'
sea_floor_depth_below_geopotential_datum (m)
' "Depth_below_X" means the vertical distance below the named surface X. The
"geopotential datum" is the geopotential reference level (level of zero geopotential)
where this is not a specifically named level such as the geoid or a reference ellipsoid.'
sea_floor_depth_below_reference_ellipsoid (m)
' "Depth_below_X" means the vertical distance below the named surface X. A
reference ellipsoid is a regular mathematical figure that approximates the irregular
shape of the geoid. A number of reference ellipsoids are defined for use in the field of
geodesy.'
height_above_sea_level (m)
' "Height_above_X" means the vertical distance above the named surface X.
"sea_level" means mean sea level, which is close to the geoid in sea areas.'
I have based the definitions on my own reading of ticket #143 and on existing
names. I'd welcome comments to improve them.
Best wishes,
Alison
------
Alison Pamment Tel: +44
1235 778065
Centre for Environmental Data Analysis Email: [email protected]
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Campus, Didcot, OX11 0QX, U.K.
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* Upper Ocean Processes Group Mail Stop 29 *
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