夏季风建立期间低层流场的变化及其与中国雨带活动的关系  

The Low-level Flow Patterns during the Establishment Process of Summer Monsoon and the Activities of Rainy Band in South China

作　　者：冯志强[1] 陈蓉[1] 

机构地区：[1]中山大学大气科学系

出　　处：《中山大学学报（自然科学版）》1993年第1期105-110,共6页Acta Scientiarum Naturalium Universitatis Sunyatseni

基　　金：国家自然科学基金

摘　　要：本文利用多年欧洲中心格点风和中国降水资料,分析了夏季风建立期间,亚洲南部及其邻近海域上低层流场的变化和雨带在中国南方的活动.结果表明,夏季风于5月中在南海地区建立.低层流场的变化主要表现为副热带高压脊从南海的东撒和气旋性气流切变线从中国西南向华南沿海的东伸.相应地,雨带有一次从南移转向北推的过程.由于5月份中南半岛——南海区域一直为西南气流所影响,因此,很难从风向来判断气流性质的变化.相对而言,雨带北移能更好地反映出夏季风向北扩展的地理位置.Using ECMWF wind data of 1980-86 and about 60 rainfall gauges ainSouth China for the period of 1970-86,this paper analyzed the variation of low-level winds over the southern part of Asia and its surrounding oceans and theactivities of organized precipitation in South China in the period of April throughJune.It is confirmed that the summer monsoon starts establishing over the SouthChina Sea area in the middle of May.This process is characterized by the east-ward withdrawal of the subtropical high ridge from this area and the stretching of acyclonic flow-shear line from southwestern China to the coast of South China,Correspondingly,the well-defined rainy band in South China changes it's movementdirection from southward to northward.Since southwesterly flows are dominantover this area in the whole month of May,it is difficult to tell the change in thenature of flows by means of wind direction.Thus,it is suggested that the locationof norhtward moving rainy bandc an be used to determine the north limit of ummernmonsoons.

关 键 词：夏季风 雨带 低层流场 中国 

分 类 号：P426.6[天文地球—大气科学及气象学]