Numerical experimental research on assimilation of cloud-free radiances from fengyun-3D microwave sounding observations over land surface

Abstract

Currently, most of the domestic numerical weather prediction systems in China only assimilate satellite microwave sounding observations over sea. There is a need to further explore the potential applications of satellite observations in the sensitive sounding channels over land. This is in line with the practical operational development needs of numerical weather prediction in China, and several approaches were proposed in this paper. These approaches aimed to solve the basic problems of accurate inversion of surface emissivity and cloud detection, including a dynamic surface emissivity calculation method constrained by wavelet data set, and an intelligent cloud detection algorithm based on GPR (Gaussian Process Regression). These methods were developed to enable the practical application of assimilating land-over satellite data in the surface-sensitive sounding channels. The research results show that: The number of land-over data entering the assimilation system was found to be equivalent to the number of sea-surface observations, significantly expanding the assimilation data source. The 24-hour and 48-hour forecast effect of heavy precipitation was found to be better than that of the operational model.