江淮地区暖区飑线中尺度观测研究

本文依据地面、高空常规资料,华东中尺度天气试验加密资料,地面温、压、湿、风、降水自记及卫星、雷达资料,对1983年4月27日晚至28日晨的江淮地区暖区飑线进行分析,揭示了飑线的一些有意思的特征。分析表明,飑线经大别山东侧自西向东传播,接近低空西南风急流轴时,对流强度发生变化;飑线过境有短时增温、伴有降性阵水特征;飑线的地面气压由β尺度的飑前中低压、飑后中高压及紧随其后的对称中低压组成。由空间结构分析看到飑前有自近地层开始的暖湿入流,飑后有来自对流层中高层的下沉气流等特征。将其和热带及美国的中纬度飑线比较发现,这次暖区飑线的气压场、温度场、风场及天气分布与经典飑线有差异,与热带及美国中纬度飑线也有区别,我们认为这是副热带地区暖区飑线的特点。

A MESOSCALE STUDY OF SQUALL LINE IN WARM SECTOR OF JIANG-HUAI AREA

In this paper, a procession of squall line in warm sector of Jiang-Huai area in April 27,1983 is analysed,which is based on the conventional data,densed data of mesoscale weather experiment of East China, temperature,pressure,humidity, wind and recording precipitation, satellite and radar data of surface. Some character of squall line which goes by DanBei Mountain propagates from west to east. When it reaches the axis of jet of south-west of low level, the convective tensity varies. The phenomena of heating of short time and shower occurs when the squall line passes. The surface pressure of squall line consists of mesoscale low in front of squall line, mesoscale high and mesoscale low behind the squall line. A warm and moist inflow is in front the squall line. This inflow comes from low level of atmosphere. There is a downdraught which comes from high level behind the squall line. The field of pressure, temperature and wind and synoptic type of this squall line are different from classical squall line and from midlatitude squall line of U. S. A. and tropical zone's.