External data means data which remains unchanged by the numerical process model. Therefore, one of its time steps suffices here. In addition to the coarse external data in this section, downscale must also read fine external data. Indeed, fine external data is the only fine data available to it.

External data from the Climate Limited-area Modelling community

For external data for the entire COSMO-DE domain, visit (also Stefan Poll’s advice):
http://www.clm-community.eu/index.php?menuid=221&reporeid=260
According to the file run_cosmo_de[3], the coordinates are:

  startlat_tot  =  -5.0  ,
  startlon_tot  =  -5.0  ,
  origin lat    =  50.0   (calculated from pollat        =  40.0),
  origin lon    =  10.0   (calculated from pollon        =-170.0),
  dlon          =   0.025,
  dlat          =   0.025,
  ie_tot        = 421    ,
  je_tot        = 461    ,
  (ke_tot       =  50

These coordinates should also be in the COSMO User Guide:
http://www.cosmo-model.org/content/model/documentation/core/default.htm
This setting will encompass the COSMO-DE domain at a resolution of 2990m. Nonetheless, a crop is necessary, as for all the complete external coarse data. Unfortunately, these files are mute on layer heights, a requirement of model1.

External data shipped with the active data

The directory with the complete active data,

 /automount/ags/tr32/COSMO_DE_ANA 

also contains coarse external data which bears a resemblance, particularily in regard to the covered area, to the external data from CLM (Climate Limited-Area Modeling Community) (cf. the section on External data from the Climate Limited-area Modelling community). It resolves 2770 m. The left image shows the crop in context.

The format of the file is Grib, but even though it contains dozens of 2-dimensional fields, it is does not feature multi-field messages, in the sense that multi.F90[2] does not produce different results in its two settings. The ECMWF (European Center for Medium-Range Weather Forecast) key ‘level’ equals zero for the entire file but the variable with the ECMWF (European Center for Medium-Range Weather Forecast) key ‘shortName’ ‘HHL’, which in all likelihood means layer height. ‘HHL’ is given on the levels 1…51 and its values decrease strictly monotonically with ‘level’.

Footnotes

fn1^. stored here as document:“Wrapper for COSMO”

fn2^. multi.F90 is an example file for ecCodes by ecCodes:
https://software.ecmwf.int/wiki/display/ECC/grib_multi