Cloud radiative fluxes are calculated for the clouds observed by cloud radar during April and May of 1998 of SHEBA (Surface Heat Budget of the Arctic) using their explicit microphysics. In this way, the dependence of the radiative fluxes to realistic cloud variability within the Arctic can be quantified. The cloud water contents and particle sizes, both liquid and ice, are determined from a suite of retrievals developed at ETL. These do not uniquely determine ice cloud optical depth as particle shape is also important yet undetermined. The shortwave and longwave radiative fluxes are calculated using Streamer (Key, J., 2001), which incorporates parameterizations for the ice cloud optical properties for various particle habits. Comparisons between the modeled and observed downward surface fluxes provide an independent check on the derived cloud properties and radiative parameterizations. The cloud radiative forcing at the surface and top- of-atmosphere is determined and explicitly connected to the cloud optical properties. The sensitivity to surface albedo is also assessed.