Abstract:Using the data of CINRAD, conventional sounding and surface observation, the radar echo cha racteristics during the mesoscale convective system (MCS) processes of 62 extreme short time severe rainfalls in Hubei Province during 2008-2015 were analyzed. Six MCS patterns were studied and summarized, including 4 linear patterns (trailing stratiform, parallel stratiform, back building/quasi stationary and training line/adjoining stratiform) and 2 nonlinear patterns (vorticity stratiform and surrounding stratiform). The study reveals that (1) the 4 linear MCS patterns and vertical distribution of ambient wind relative to the convective line component are basically consistent with the results of earlier studies. (2) The typical characteristic of the nonlinear vorticity stratiform MCS is that the spiral vortex convective echo bands are enwrapped by the wide range stratiform cloud rain echo. The vorticity stratiform MCSs are mostly formed near the shear line in front of the southwest vortex, which is mainly related to the triggering and organization of the mesoscale vortex system in the boundary layer over the transitional zone between mountain and plain of western Hubei. (3) The back building/quasi stationary MCSs mostly occur on the windward slope, which is related to the blocking function of the mesoscale terrain and the organizational role of the cold pool. (4) The vorticity stratiform pattern has the longest duration and the largest range, while the surrounding stratiform pattern is the shortest in duration.