青藏高原对冷空气爆发影响的个例分析(一)

本文通过对1979年4月10—13日在我国的一次寒潮爆发过程进行了有、无地形及修改地形的数值试验和对比分析,发现高原地形对冷空气活动强度及路径等有明显的影响:(1)由于高原地形的存在使冷空气快速沿地形边缘向南推移,冷锋偏南,给我国平原地区带来较大的降温及较多的降雨。(2)这种冷锋的移动快而达到很偏南的纬度主要是低层冷空气沿高原地形边缘绕流所产生的。(3)如果高原大地形不存在,这时冷空气直侵印度,给印度北方带来强降温。

A CASE STUDY OF THE EFFECT OF TIBETAN PLATEAU ON THE OUTBREAK OF COLD AIR

In this paper we have discovered the following main effects of Tibetan Plateau on the intensity of cold-outburst and its trajectory through numerical experiments with orography and without orography for the case in the period of 10-13 April 1979. ( 1 ) Owing to the broken action of Tibetan Plateau, the cold air moves fast southeastward along its north and east periphery, the cold front reaches far to the southern area and brings more temperature drop and more rainfall in the plains of China which lies to the east of the Plateau. ( 2 ) The cold front reaching far low latitude is caused by the lateral boundary action of Tibetan Plateau which accelerates the cold air flows around its periphery. ( 3 ) If Tibetan Plateau did not exist, the cold air would straight rush to India and would bring strong temperature drop there.