Retrieval of Cloud Radiative Properties from FY-2C Satellite Data

This paper describes the theories of remote sensing and algorithms for retrieving cloud radiative properties such as cloud optical thickness, cloud particle effective radius, and cloud top temperature, using multispectral images such as visible, middle-infrared, and far infrared channel reflectance, and brightness temperature from the Visible and Infrared Spin Scan Radiometer (VISSR) sensor of FY-2C satellite. Based on the sensitivity analysis between FY-2C visible, middle-infrared, far infrared channel radiance, and radiative parameters such as cloud optical thickness, cloud particle effective radius, cloud top temperature, surface albedo, and surface temperature by radiative transfer calculations, an iterative algorithm for retrieval of cloud optical thickness, cloud particle effective radius; and cloud top temperature simultaneously by three channels of FY-2C sensor is developed and applied to experimental study. The retrieval results are compared with MODIS cloud products. Finally, the retrieval errors are analyzed. Conclusions are as follows: 1) There is a good correspondence between observed data of FY-2C channels and retrieved cloud parameters, standard deviation (SD) of iterative algorithm is reasonable (0.89%); 2) A comparison with MODIS cloud products shows a good coherence of cloud optical thickness and cloud particle effective radius between FY-2C and MODIS, while the cloud top temperature of FY-2C retrieval results is lower than that of MODIS. In view of lower-valued 11μm channel radiance from FY-2C, the precision of this algorithm is equivalent to that of MODIS.