摘要
定义了一个反映东亚夏季大尺度季风强度的指数，计算了夏季逐月及季的东亚季风指数（１８７３～１９８９年）。用近４０年资料研究了东亚夏季风与我国夏季大尺度天气的关系。指出，强夏季风时，我国夏季大范围高温。东亚夏季风与我国夏季降水的关系则表现在夏季雨带的南北位置上。强夏季风时，雨带偏北。夏季雨带位置偏南均与弱季风有关。长江中下游夏季的涝年与弱季风有关，而强夏季风时，长江中下游经常是旱年。最后，研究了强、弱夏季风年时的北半球５００ｈＰａ环流异常特征，结果表明，东亚夏季风强度是造成我国夏季气温、降水异常的主要原因。
In this study, the East Asian summer monsoon (EASM) intensity index is defined. The 1873￣ 1989 EASM summer monthly intensity index is calculated. Studies of the relation of the EASM to the rainfall and temperature over China by using the data for the past 40 years show that when a strong monsoon occurs China will experience an extensive high temperature in summer. The EASM effect on summer rainfall in the mainland is displayed in the meridional position of the rainbelt. The position of the summer belt is northward (southward) of its mean when the summer monsoon is strong (weak). Flooding (drought) years over the middle and lower reaches of the Changjiang River are related to the weak (sirong) monsoon. Finally, the Northern 500 hPa summer circulation features for the years of the strong and weak EASM are examined and the results indicate that the EASM intensity represents a main factor for the temperature and rainfall anomalies over China in summer.
出处
《大气科学》
CSCD
北大核心
1996年第5期575-583,共9页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金
关键词
季风
东亚季风
大尺度天气
气候异常
East Asian summer monsoon intensity index rainbelt middle and lower reaches of the Changjiang River
