春季江南锋生结构的分析

On the Structure of the Frontogenesis over Southern region of the Yangtze in Spring

本文通过对一次典型的春季江南锋生的气象要素场的时空变化进行了分析,讨论了锋生过程的空间结构.结果指出:江南锋生是发生在对流层下部南支西风槽前,主要是通过低层辐合流场促使锋生区强烈的增温增湿来实现的.其中水汽输送对锋生过程有着十分重要的作用;有利的垂直环流又加速了锋生的怍用.此外,还从流场和变压场论证了江南锋生之初具有暖锋性质.这种现象的揭露对春季江南锋生的分析和预报有所助益.

Bythe analysis of time and space variation of the meteorological elements inthe course of a typical frontogenesis over Southere region of the Yangtze in spring,the essay surveys the space structure and characteristics of thisfrontogenesisprocess.It is found that the frotogenesis appears in the lower troposphere infront of the trough-line within the southern branch of the westerlies.Themaintance of the frotnogenesis chiefly depends upon the horizontal convergenceifeld of the flow in the lower troposphere and therein,the moisture transportplays an important role in this process.The advantageous vertical circulationaccelerates the frontogenesis.Besides,based on the analyzed results of the fieldsof the flow and the pressure tendency,at the begining of the process,there appearsin frot a warm condition.These results may help to analysis and prediction ofthe frontogenesis.