QUANTIFYING THE CONTRIBUTIONS OF ENVIRONMENTAL PARAMETERS TO SATELLITE-RETRIEVED SURFACE NET LONGWAVE RADIATION ERROR: AN EXAMINATION ON CERES DATASET IN CHINA

摘要

Error source analyses are critical for the satellite-retrieved surface net longwave radiation products. In this study, we evaluate the error sources of the Clouds and the Earth's Radiant Energy System (CERES) project Single Scanner Footprint (SSF) net longwave radiation (NLW) product (monthly mean, 1° equal area) at 11 sites from July 2000 to December 2007 in China. Results show that cloud fraction, land surface temperature and atmospheric temperature error dominate the NLW error, with respective error contributions of ～-20, ～15, and ～10 W/m~2, while the total precipitable water vapor has a weak influence. Spatially, due to strong algorithm sensitivity and large product errors, surface temperature and cloud fraction have the most contributions to error sources, especially in northern China, while the atmospheric temperature significantly affects NLW in southern China because of its large product errors. To improve NLW, the large errors of these parameters should be reduced. Our study identifies the dominant error sources and should be helpful to improving the CERES NLW in China.