Solar irradiance at top of atmosphere

For solar irradiance at the top of the atmosphere, you can choose a spectrum with a fixed shape specified in the radiative transfer code or you can read a time-varying spectrum from a NetCDF file. To use the shape of the solar spectrum specified in the radiative transfer code, set:

ok_suntime_rrtm = n

in config.def and choose the value of the solar constant to scale this spectrum:

solaire = 1365

(for example), also in config.def. To read the spectrum from a NetCDF file, set:

ok_suntime_rrtm = y

in config.def. Then the gcm program needs the file solarforcing.nc, containing variables tsi, which is the solar constant, and ssi_frac, which is the fraction in each of the nsw bands, daily, for 1 year (solarforcing.nc has to be prepared with the right number of days).