Clear sky atmospheric radiative transfer: a model intercomparison of shortwave irradiances

This study consists of an intercomparison of clear-sky shortwave irradiances calculated by the Doubling
Adding model of KNMI (DAK) and the Simple Model of the Atmospheric Radiative Transfer of Sunshine (SMARTS).
The DAK and SMARTS models are run with identical input (state profiles, water vapour, ozone, aerosols, etc.) and the
differences between the models are examined in terms of broadband shortwave irradiances as a function of solar zenith
angle. The DAK and SMARTS models agree very well. For a pure Rayleigh atmosphere the differences in the irradiances
are less than 5 W/m2. For cases with aerosols the differences of the irradiances are within 10 W/m2.