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Some users are interested on geopotential (z) of the different model levels (ml). This Python script will allow you to compute it. The starting point is the geopotential and the pressure (z and lnsp) on the surface. The output will be written in grib GRIB format, providing the geopotential in m^2/s^2 for each level. (Note that you can get the heigh height in meters if you divide the geopotential by the gravity of Earth (9.80665 m/s^2))
- It requires Python and GRIB-APIecCodes
- Input format has to be gridded, not spectral
- The script is based on the Metview macro mvl_geopotential_on_ml, code from Nils Wedi, IFS documentation:
For this use case, you need to retrieve in grib GRIB format both temperature (t) and Specific humidity (q) for each model level. Besides, you need both surface geopotential (z) and logarithm of surface pressure (lnsp) for model level = 1. Both files have to be synchronized using the same class, stream, date, time, step and gridType. The script will iterate through the date/time/step parameters, allowing you to get the values for multiple times.
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This example will compute the geopotential on the 2015-10-08 time 00 operational analysis model levels (137). Below you can see the MARS user documentation request used to retrive retrieve both files. You can set a different class/stream/type for the input data. The gribType and resolution can also be changed.
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