Retrieval of the vertical profile of the cloud effective radius from the Chinese FY-4 next-generation geostationary satellite

Abstract. The vertical profile of the cloud effective radius (Re) reflects the precipitation-forming process. Based on observations from the first of the Chinese next-generation geostationary meteorological satellites (FY-4A), we established a new method for objectively obtaining the vertical temperature vs Re profile. Re was calculated using a bi-spectrum lookup table and cloud clusters were objectively identified using the maximum temperature gradient method. The Re profile in a certain cloud was then obtained by combining these two sets of data. Compared with the conventional method used to obtain the Re profile from the subjective division of a region, objective cloud cluster identification establishes a unified standard, increases the credibility of the Re profile and facilitates the comparison of different Re profiles. To investigate its performance, we selected a heavy precipitation event from the Integrative Monsoon Frontal Rainfall Experiment in summer 2018. The results showed that the method successfully identified and tracked the cloud cluster. The Re profile showed completely different morphologies in different life stages of the cloud cluster, which is important in the characterization of the formation of precipitation and the temporal evolution of microphysical processes.