Abstract:Using the data of CINRAD, conventional sounding and surface observation, the radar echo characteristics during the mesoscale convective system (MCS) processes of 62 extreme shorttime severe rainfalls in Hubei Province during 2008-2015 were analyzed. Six MCS patterns were studied and summarized, including 4 linear patterns (trailingstratiform, parallelstratiform, backbuilding/quasistationary and training line/adjoining stratiform) and 2 nonlinear patterns (vorticitystratiform and surroundingstratiform). 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 vorticitystratiform MCS is that the spiral vortex convective echo bands are enwrapped by the wide range stratiformcloud rain echo. The vorticitystratiform 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 backbuilding/quasistationary 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 vorticitystratiform pattern has the longest duration and the largest range, while the surroundingstratiform pattern is the shortest in duration.