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, alison.pamment at stfc.ac.uk 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: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Campus, Didcot, OX11 0QX, U.K.
>
>
>
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--
*******************************************************
* Nan Galbraith Information Systems Specialist *
* Upper Ocean Processes Group Mail Stop 29 *
* Woods Hole Oceanographic Institution *
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Received on Wed May 24 2017 - 09:09:03 BST
