The Impact of Surface Properties on Downward Surface Shortwave Radiation over the Tibetan Plateau

The complexity of inhomogeneous surface–atmosphere radiation transfer is one of the foremost problems in the field of atmospheric physics and atmospheric radiation. To date, the influence of surface properties on shortwave radiation has not been well studied. The daily downward surface shortwave radiation of the latest FLASHFlux/CERES(Fast Longwave And Shortwave Fluxes Time Interpolated and Spatially Averaged/Clouds and the Earth's Radiant Energy System) satellite data was evaluated against in situ data. The comparison indicated that the differences between the two data sets are unstable and large over rugged terrain compared with relatively flat terrain, and the mean absolute error of the satellite products reaches 31.4 W m-2(12.3%) over rugged terrain. Based on the SSF(single satellite footprint)/CERES product, the influence of surface properties on the distribution of downward surface shortwave radiation(DSSR) was analyzed. The influence of surface properties on DSSR over the Tibetan Plateau is about twice as large as that in two other regions located at the same latitude(eastern China–western Pacific and subtropical North Pacific). A simulation was carried out with the help of the I3RC(International Intercomparision of Three-Dimensional Radiation Code) Monte Carlo 3D radiative transfer community model. The results showed that DSSR increases as surface albedo increases. Moreover, the impact of surface albedo on DSSR is larger if the spatial distribution of clouds is more non-uniform. It is hoped that these results will contribute to the development of 3D radiative transfer models and the improvement of satellite inversion algorithms.