Dear Jonathan,
Thank you for the quick reply.
> The depth variable in your example is a 4D auxiliary coordinate variable. It
> is CF-compliant, but it's not a CF parametric vertical coordinate variable.
OK. Thanks. That was what I hoped for.
Best wishes,
Daniel
Am 15.10.2019 um 19:31 schrieb Jonathan Gregory:
> Dear Daniel
>
>> Does "Parametric Vertical Coordinates" mean that there is a mathematical
>> function, which describes the relation between the relevant (auxiliary)
>> coordinate variables and the parametric vertical coordinate?
>
> In section 4.3.3, it means that the physical vertical coordinate z(k,j,i),
> where i,j are indices of the horizontal dimensions and k of the vertical,
> can be written as as a mathematical function
> z=f(V1(k)[,V2(k),...],H1([t,]j,i)[,H2([t,]j,i)...])
> where V1,... depend only on level, and H1,H2,... depend only on horizontal
> position (and perhaps on time). I think that describes all the cases of
> Appendix D, but someone may correct me! The entries in App D describe the
> physical vertical coordinate and how to compute it with the formula f.
>
>> Speaking in terms of the example provided further below: Value of `depth` is
>> a `f(time, lev, lat, lon)`, whereas `f` is a mathematical function with
>> considerably less parameters than `depth` has values. Then `depth` is a
>> parametric vertical coordinate.
>>
>> Formulated the other way arond: Is `depth` NOT a parametric vertical
>> coordinate if its values are somehow set by hand (by a human), calculated by
>> some nested if-clause, or by some iterative procedure?
>>
>> If `depth` is not a parametric vertical coordinate in this sense, am I
>> allowed to use it in a CF-compliant file?
>
> The depth variable in your example is a 4D auxiliary coordinate variable. It
> is CF-compliant, but it's not a CF parametric vertical coordinate variable.
>
>> Example:
>>
>> ...
>> int lev(lev):
>> lev:standard_name = "model_level_number" ;
>> lev:long_name = "model_level_number" ;
>> lev:positive = "down" ;
>> lev:units = "1" ;
>> double depth(time, lev, lat, lon);
>> depth:long_name = "depth" ;
>> depth:positive = "down" ;
>> depth:standard_name = "depth" ;
>> depth:units = "m" ;
>> depth:axis = "Z" ;
>> float some_data_variable(time, lev, lat, lon);
>> some_data_variable:standard_name = "some_standard_name" ;
>> some_data_variable:units = "some_unit" ;
>> some_data_variable:coordinates = "depth"
>
> Best wishes
>
> Jonathan
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--
Daniel Neumann
Abteilung Datenmanagement
Deutsches Klimarechenzentrum GmbH (DKRZ)
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Phone: +49 40 460094-120
FAX: +49 40 460094-270
Email: daniel.neumann at dkrz.de
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Received on Tue Oct 22 2019 - 08:18:41 BST
