ASSESSMENT OF TWO SATELLITE-BASED LAND SURFACE SHORTWAVE DOWNWARD RADIATION DATASETS OVER THE TIBETAN PLATEAU

Land surface shortwave downward radiation (SWDR), as one of major components of the surface radiation budget (SRB), plays an important role in the fields of atmospheric, oceanic, and land processes, and ultimately influences the Earth's climate as well as the matter and energy cycle of the earth system. Currently, regional or global SWDR can be obtained either from reanalysis products or from satellite observations based on statistical or physical-based retrieval models. Although great efforts have been made to assess the applicability and accuracy of those different SWDR datasets, few studies have been conducted to evaluate the performance of the Clouds and the Earth's Radiant Energy System Synoptic (CERES-SYN) Edition 3a and Himawari-8 SWDR datasets over the Tibetan Plateau. In this study, the both SWDR datasets are validated against in-situ data at 11 ground sites from the China Meteorological Administration (CMA). It is found that the Himawari-8 SWDR product has a slightly higher accuracy in these two SWDR datasets but with a significantly higher spatial resolution (5km). The mean bias is 1.7 W/m(2) for CERES-SYN and -1.6 W/m(2) for Himawari-8, respectively, the root mean square errors (RMSE) are 31.3 W/m(2) for CERES-SYN and 31.2 W/m(2) for Himawari-8, respectively. Mean coefficient of determination (R-2) of the two datasets are both over 0.8. It is clearly that CERES-SYN tends to overestimate SWDR somewhat while the Himawari-8 has slight underestimation over the Tibetan Plateau. The findings in this paper can be valuable for hydrological, ecological, agrometeorological and biogeochemical applications and researches.