摘要
根据夏季东亚季风区内季风环流异常所反映行星尺度扰动的强弱,来定义东亚大气遥相关指数IEA。分析表明,它能较清楚地反映夏季西太平洋副高脊线和西伸脊点位置与东亚季风系统各支季风气流的变化。并揭示当IEA偏强(弱)时,东亚季风系统内的热带季风环流出现异常加强(减弱),副热带季风环流出现异常减弱(加强),而中高纬度季风环流又出现异常加强(减弱),三者之间的关系。分析还表明,IEA异常前期,具有明显ENSO循环位相特征,冬季热带太平洋SST、OLR异常,以及对流层高层风异常,可以作为前期征兆信号。该指数变化与我国夏季降水异常分布密切相关,并清楚地反映出东亚季风系统内热带季风环流与副热带季风环流及其各支季风气流异常对我国夏季降水的影响,为该指数在气候监测与预测中的应用提供一定的物理依据。
Based on the abnormal dynamic structure of the East Asian summer monsoon circulation at 500 hPa, an East Asian Atmosphere Teleconnection Pattern Intensity Index （ IEA ） is defined. The main results are as follows： IEA can clearly indicate the location variations of the ridge line and its west： ernmost point of the Western Pacific Subtropical High and the wind intensity variations in the East Asian summer monsoon. It reflects that in East Asian monsoon system, the tropical monsoon circulation is correlated with the mid-high latitude monsoon circulation and is inversely correlated with the subtropical monsoon circulation. It is found that ENSO cycle has distinct phase features before abnormal IrA occurring, the anomalies of u-wind component at 200hPa, OLR and SST anomalies over the Pacific in the previous winters could be regarded as a signal before abnormal IEA.
出处
《气象科学》
CSCD
北大核心
2009年第1期46-51,共6页
Journal of the Meteorological Sciences
基金
福建省科技计划项目“东亚夏季风变异及其影响闽台旱涝机理和预测方法研究”(2004Y021)
关键词
东亚夏季风
中国夏季降水
大气遥相关
East Asian summer monsoon Summer rainfall in China Atmosphere teleeonnectionpattern
