A COMPOSITE DIAGNOSTIC STUDY OF HEAVY RAIN CAUSED BY THE NORTHEAST COLD VORTEX OVER SONGHUAJIANGNENJIANG RIVER BASIN IN SUMMER OF 1998

Nine typical heavy rain events caused by the northeast cold vo rtex over Song huajiang-Nenjiang basin in China have been chosen and their composite of physical variables w ere also done.The results show that the blocking high over East Asia, the w est Pacif ic subt ropical high, the no rtheast cold vo rtex and summer monsoon moisture transportation play quite impo rtant roles in the persistent heavy rain over the Song huajiang-Nenjiang region.The special horizontal and vertical st ructures of the cold vortex itself result in the heavy rain mainly occurring to the east of the cold vortex center.