东亚夏季风对山东夏季降水的影响

Impacts of the East Asian Monsoon on the Summer Rainfall in the Shandong Area

对2种东亚夏季风指数进行了对比分析,选择1种能较好地表征山东夏季降水的夏季风指数。研究了山东旱涝年以及强弱季风年500hPa高度场、850hPa风场、热带洋区OLR场、西太平洋副热带高压等异常分布特征,并初步探讨了影响山东夏季降水的物理机制。结果表明,海陆热力差指数是1种较适合研究山东夏季降水的东亚夏季风指标。强(弱)指数年,南海-热带西太平洋地区对流活动较常年偏强(弱),热带东太平洋地区对流活动偏弱(强),Walker环流偏强(弱),北半球500hPa环流形势呈EAP(负EAP)遥相关型,副热带高压偏北偏强(偏南偏弱),山东夏季以多雨(少雨)年份居多;春夏季南海-热带西太平洋地区对流活动与山东夏季降水之间存在着遥相关关系,两者遥相关的可能机制是热带强迫所激发的大尺度准定常Rossby波的传播。

A contrastive analysis of two indexes of the east Asian monsoon reveals that there is a relation between the index of sea-land thermal difference and the summer rainfall in Shandong Province. Through Analysis of the geopotential height field at 500hPa, the Subtropical High, OLR in the tropical areas, etc., shows that there are periodic oscillations of 2-6 years in the index of sea-land thermal difference, which is similar to that of summer rainfall in ShanDong Province, The year with a strong （weak） index is associated with strong （weak） convective activities occurring in the tropical Indian Ocean and tropical west Pacific and weak （strong） convective activities in the tropical east Pacific and EAP （negative EAP） pattern in which the Subtropical High is mainly in the north （south） and more （less） summer rainfall appears in Shandong.