The z-grid of optical properties is determined by the atmosphere_file,
and, if specified, by other profile files like dens_file, rh_file,
or refractive_index_file.
Additional levels might be introduced by the zout
option and the second argument of the altitude option. By default
(if zout_interpolate is not specified) levels introduced
by the zout option will not affect the optical property
profiles, that is, the optical properties are constant within the layers specified by
the atmosphere_file and profile files.
If zout_interpolate is specified, the atmospheric profiles (tracegases, temperature ...)
are interpolated to the levels introduced by zout, and optical
properties are determined from the interpolated atmospheric properties.
If heating_rate or rte_solver polradtran is specified, zout_interpolate
will also be automatically activated.
zout_interpolate generally causes smoother variation of the optical properties.
Arve Kylling
2010-03-10