云南德宏“7.5”特大洪涝与滇缅高压

“7.5” Heavy Rainfall in Dehong,Yunnan Province and Burma High

利用MICAPS系统资料对2004年7月5日云南省德宏州西部出现的突发性大暴雨、局部特大暴雨天气进行诊断分析,结果表明此次强降水与滇缅高压的建立有关,滇缅高压西侧强西南气流的存在和滇缅间低空急流的建立,为此次强降水提供了丰富的水汽和位势不稳定能量;而高原高压的南压和西藏东部至川西T形切变槽的加深东南移,有利于引导北方冷空气南下渗入。过程期间,物理量场表现出强水汽输送辐合及上升运动;冷空气与暖湿气流及特殊地形的综合作用激发出中α尺度降水云团,造成此次强降水。

Based on the data of MICAPS system, the abrupt heavy rain event in Dehong, Yunnan province on July 5, 2004 is analyzed. The result showed that the event had something to do with the establishment of Yunnan-Burma high. The low-level tropospheric jet supplied indispensable condition of high unstable geopotential energy and plenty moisture. Tibetan high southward moving and T-shape shear line and trough-line from east of Tibet to west of Sichuan province deepening and southeastward moving were helpful to guide northern cold-air mass moved southward. The strong moisture transportation and convergence and strong updraft, mesoscale cloud cluster stimulated by synthetical effect of cold-air, warm and damp air stream and particular terrain lead to the heavy rainfall.