2007年我国北方秋季连阴雨的天气学成因分析

Analysis of the Weather Cause of the Autumn Continuous Rain in North of China in 2007

利用数值预报模式客观分析资料，分析了2007年秋季连阴雨时期大气环流特征、影响系统和物理要素的平均场，揭示了该次连阴雨的天气学成因。结果表明：该次连阴雨的主要成因是大气环流异常且稳定维持，乌拉尔山高压脊偏强，西太平洋副热带高压比常年偏强，脊线偏北；稳定的环流背景下，副高西侧盛行的偏南气流及700hPa西风带短波槽沿副高西北缘东移，是造成连续降水的主要影响系统；动力条件、热力条件、水汽输送条件均有利于黄河流域形成降水。

Based on the objective analysis data of the numerical prediction model, the atmospheric circulation characteristics, influence system and physical elements average field of the continuous rain were analyzed in autumn 2007 and it revealed the weather causes of the continuous rain. The result show： it caused this continuous rain that the atmospheric circulation was abnormal and stable ant the high pressure ridge on Ural and the west Pacific subtropical high were stronger than normal. The effect system of the continuous rain was the south airflow in the west of the subtropical high and short-wave tough of westerlies in 700hPa moving along the subtropical high favorable dynamic condition, thermal condition and vapor transmission condition for the continuous rain river.