Set the bottom level in the model atmosphere provided in
atmosphere_file to be at the given altitude above sea level (km).
altitude 0.73 # Altitude of IFU, Garmisch-Partenkirchen
altitude 0.73 0.5
The profiles of pressure, temperature, molecular absorbers,
ice and water clouds are cut at the specified altitude.
The aerosol profile is not affected by altitude but starts
right from the model surface. This is a convenient way for the user to calculate the
radiation at other altitudes than sealevel. Note that altitude is very different
from zout where the radiation is calculated at an altitude of zout
above the surface. E.g. to calculate the radiation field 1 km above the surface
at a location at 0.73 km above sealevel, one would specify 'altitude 0.73'
and 'zout 1.0'.
If an altitude is specified which is below the lowest level in the
atmosphere_file, the atmospheric profiles are extrapolated assuming a constant
gradient for temperature and mixing ratios.
A second optional argument may be given to altitude as e.g.
Here the bottom level will be at 0.73 km and the vertical resolution of the model atmosphere will be redistributed to have a spacing between levels specified by the second number, here 0.5 km, starting however from 0km. (Levels 0.73, 1., 1.5 … will be added to the original atmosphere grid and optical properties are devided into the new layers. In order to use interpolated properties use zout_interpolate. See verbose output for details.) Be aware that specifying a fine vertical spacing will produce many layers thus increasing the computing time. Also the radiative transfer equation solvers implemented in Fortran 77 might need to have some array sizes increased (see src_f/DISORT.MXD).