1999年上海梅雨异常的环流特征及其成因

对１９９９年上海地区入梅早、出梅迟、梅雨期长、梅雨量超历史纪录的环流特征和原因作了初步统计分析，其中分别讨论了西太平洋副带高压强度及脊线位置、东亚夏季风强度经指数及爆发迟早、低续热带地区对流活动、台风的频数及移劝路径等天气气候因素与１９９９年上海地区梅坏处主异常的关系，结果表明：１９９９年副热带高压强度偏弱、主体位置偏南、偏东，东亚夏季风爆发早、强度指数偏弱，ＩＴＣＺ赤道辐合带）不活跃，台风位置偏

The Circulation Features and its Formation Cause of the Meiyu Anomaly in Shanghai in 1999

The circulation features and its formation cause in Shanghai in 1999 were investigated,including mei yu quantity,mei yu period,the beginning and ending of mei yu,and its relationship with the subtropical high,East Asian summer monsoon intensity index,the convective activity in tropical zone and typhoon were discussed.The results show that the intensity of subtropical high is weaker,the ridge line of subtropical high is leaning to south and east,the East Asian summer monsoon intensity index is weaker and begins earlier,ITCZ is not active, typhoon sums are less, and they are the formation factors of the mei yu anomaly in Shanghai in 1999.