Forcing inside the atmosphere
The concentration of greenhouse gases: \(\ce{CO2}\), \(\ce{CH4}\),
\(\ce{N2O}\), CFC-11, CFC-12, should be set in file config.def, with
corresponding variable names CO2, CH4, N2O, CFC11, CFC12. These gases
are assumed to have a uniform concentration in the atmosphere so you
just provide a scalar for each gas.
Ozone
Ozone, contrary to the greenhouse gases mentioned above, cannot be
assumed to have a uniform concentration in the atmosphere. So we have
to provide a space-time distribution of ozone. This is controlled by
the run-time parameter read_climoz in config.def. Values allowed
for read_climoz are:
read_climoz= 0: analytic expression for the ozone field (seephylmd/ozonecm_m.f90)read_climoz= - 1 (use withsolarlong0= 1000): ozone field made symmetric with respect to the equator, for use with annual mean insolation (used for aquaplanet runs)read_climoz= 1: read day-night average of ozone field from a NetCDF file (this is what you want for CMIP 6 input).read_climoz= 2: also read daylight average from the same file (good idea with Reprobus CMIP 5 input and if you run LMDZ with a few model layers in the mesosphere).
With read_climoz = 1 or 2, the input NetCDF file climoz.nc must
contain monthly averages of ozone mole fraction as a function of
horizontal position, pressure level and month for one calendar
year. The horiontal position may be given by longitude and latitude or
just latitude if the values of ozone mole fraction are zonal
averages. The horizontal grid in climoz.nc may be different from the
grid we want to use in LMDZ. Horizontal regridding of climoz.nc to
the grid of the gcm is done by program ce0l, producing the file
climoz_LMDZ.nc. See figure below.
