Analysis on characteristic cloud parameters of a heavy rain event ased on satellite cloud images from FY-3A

Using the FY-3A/MERSI data combined with the upper-air and surface observations an analysis is made on the satellite cloud images and characteristic parameters of a rainstorm cloud occurred on June 28, 2009 in Hubei province. The results show that V-shaped cloud (wedge-shaped cloud) is a sign of strong convection originated, and the wedge tip region usually is accompanied by the lowest cloud top temperature and the biggest TBB gradient. Short-term severe precipitation often occurs in the position where strong updraft motion exists,namely, the unique structures of convective cloud such as the overshooting cloud top, texture and shadow can be clearly identified in the high-resolution visible image. Major pixels of the strong convective cloud are classified as“cumulonimbus”cluster group by fuzzy C-mean clustering method, and membership coefficient reaches 0.81. One-hour rainfall intensity has a good positive correlation with the cloud optical thickness / effective particle radius and has a negative correlation with the blackbody brightness temperature.