梅汛期暴雨青藏高压东侧高低空环流的研究

The study on the circulation of high altitude and low altitude of the east of Qingzang high in the time of torrential rain

本文利用1998-05-01～07-31全球再分析场(NCEP)资料,对长江中下游梅汛期暴雨中青藏高压东部的高低空环流特征以及它与暴雨的关系进行了分析讨论。得出暴雨时段高空150 hpa西风急流轴与东风急流轴之间的纬距大于非暴雨时段大约10个纬度;高空青藏高压北侧西风急流强度较大,从而引起青藏高压反气旋环流加大,使长江中下游高空偏北气流加大,低层850 hpa在长江中下游以南有1个平均风速大于12 m/s的西南急流中心,它与高空辐散相接合形成较强的上升运动。

The character of circulation of high altitude and low altitude and the relation torrential rain in Meiyu period of middle and lower reaches of Yangze River are analyzed and discussed by employing NCEP data from 1^st,May, 1998 to 31th,July, 1998. The result indicates the distance between latitude of the westerly jet and latitude of the easterly jet is about ten latitudes in average field. The intensity of the westerly jet of north of Qingzang High is stronger in the time of torrential rain. It leads to that the anti-cyclone of Qingzang High is stronger and the north air current of high altitude of middle and lower reaches of Yangze River is stronger. There is a the center of the southweste jet in 850hpa low altitude, its average wind velocity is faster than 12 m/s. It combines with divergence of high altitude to form stronger movement of rising.