东亚副热带夏季风与山西省夏季降水的关系

利用山西省58个台站1960~2009年夏季降水资料和NCAR/NCEP逐月再分析资料,在考虑蒙古中纬度地区和西太平洋副热带地区大气环流特征的基础上,根据海陆气压差建立了东亚副热带夏季风指数,并研究该指数与山西省夏季降水的关系。结果表明:东亚副热带夏季风指数ISSM表现出明显的长期气候变化趋势,20世纪60~70年代以正值为主,而70年代末之后以负值为主。ISSM指数能够很好地反映出蒙古低压和西太平洋副热带高压系统的典型特征。东亚副热带夏季风越强对应着山西夏季降水越多,山西中部、南部偏东的大部分区域属于东亚副热带夏季风控制区,运城盆地、西部高原山地、忻州盆地、大同盆地等属于东亚副热带夏季风西北边缘区。

Analysis of Correlation Between East Asian Subtropical Summer Monsoon and Summer Precipitation in Shanxi Province

Based on the 50 years （1960-2009）rainfall data from 58 meteorological stations in Shanxi Province and monthly reanalysis data of NCAR/NCEP,and on the basis of considering the atmospheric circulation characteristics over the western Pacific subtropical ar-ea and Mongolia middle latitude area,the east Asian subtropical summer monsoon index （Issm ）was established according to the sea pressure difference between land and sea,and the relationship between Issm and summer rainfall in Shanxi was investigated.Results show that Issm displayed the variability on the decadal scale,and the positive Issm mainly occurred in the 1960s and 1970s,and the neg-ative Issm mainly occurred after the end of 1970s.The Issm could reflect the variations well for both the low pressure in Mongolia and the subtropical high in the western Pacific.The stronger the East Asian summer monsoon was,the more summer rainfall was in Shanxi. The central and southeast regions of Shanxi Province belong to the East Asian subtropical summer monsoon-controlled areas,while Yuncheng basin,Xinzhou basin,and Datong basin belong to the boundary belt of East Asian subtropical summer monsoon-controlled areas.