Cloudy Sky RRTM Shortwave Radiative Transfer and Comparison to the Revised ECMWF Shortwave Model

An important step toward improving radiative transfer codes in general circulation models (GCMs) is their thorough evaluation by comparison to measurements directly, or to other data-validated radiation models. This work extends the clear-sky shortwave (SW) GCM evaluation presented by Iacono et al. (2001) to computations including clouds. The rapid radiative transfer model (RRTM) SW radiation model accurately reproduces clear-sky direct beam fluxes from the Line-By-Line Radiative Transfer Model (LBLRTM) (Clough and Iacono 1995), and direct and diffuse fluxes from Code for Highresolution Accelerated Radiative Transfer with Scattering (CHARTS; Moncet and Clough 1997). All three models were developed at Atmospheric and Environmental Research, Inc. (AER) with support from the Atmospheric Radiation Measurement (ARM) Program and have been carefully evaluated with ARM measurements.