Preliminary validation of cloud amount product of FengYun-3D satellite

Abstract

China’s Fengyun-3D satellite (FY-3D), which can obtain global cloud amount data, was launched in November 2017. In this study, we qualitatively and quantitatively compare the cloud amount products from FY-3D and the moderate resolution imaging spectroradiometer (MODIS) AQUA in July and October,2018. The results show that the global spatial distribution characteristics of the FY-3D cloud amount products is consistent with that of MODIS. The distributions of the cloud amount of the two products are more similar in October, but theFY-3D cloud amount data are generally higher than the MODIS cloud amount data. After strict space-time matching, the matched samples are used for quantitative accuracy evaluation. In July 2018, the absolute error of the FY-3D cloud amount relative to MODIS is 4.5, the relative error is 0.11, the deviation is 1.68, the error standard deviation is 12.11, and the correlation coefficient reaches 84.8%. In October 2018, the absolute error of the FY-3D cloud amount relative to MODIS is 3.20, the relative error is 0.05, the deviation is 1.68, the error standard deviation is 6.38, and the correlation coefficient is 93.4%. The global error distribution shows that at mid-low latitudes, the quality of the two products is similar and the error ranges between -10 and 10%, while at high latitudes the error is relatively large. FY-3D cloud amount products can be used in studies of the global climate and climate change.