晋北地区春季降水异常的环流特征及其与海温的关系分析

摘要

利用美国国家环境预报中心(NCEP)再分析资料、ICOADS的SST格点资料以及晋北地区18个台站1960-2008年春季降水资料,采用合成分析等方法,对影响晋北地区春季降水异常的海-气因子进行分析.结果表明,晋北地区春季多雨年中高纬度500hPa呈现“东高西低”的分布特征,在乌拉尔山以东至贝加尔湖以西一带有低压槽加强,晋北地区处于低槽的东南侧,西北冷空气与东南暖湿气流多交汇于华北一带,因而造成春季多雨天气.与此相反,在少雨年冷、暖空气势力较弱,弱的辅合区位于蒙古中部,不利于晋北地区春季降水的产生.通过分析晋北春季降水与海温异常的相关关系得出,当前期ENSO暖位相时,晋北地区春季降水偏多;前期ENSO冷位相时,晋北地区春季降水偏少.研究结果有利于了解晋北地区旱涝异常成因,为短期气候预测提供理论依据.%Based on NCEP reanalysis data,the ICOADS SST grid data and the observed data of spring precipitation from 18 meteorological stations in Northern Shanxi during 1960-2008,the air-sea factor that caused abnormal spring precipitation in Northern Shanxi was investigated by using composite analysis method.The results showed that the 500hPa geopotential height had the distribution characteristics with "high in the east and low in the west" in the spring of rainy years in Northern Shanxi.From the east of the Ural Mountains to the West of Lake Baikal,trough was strengthened and Northern Shanxi was in the southeast of the trough.The intersect of the cold air from Northwest and the warm air from Southeast in North area always resulted in the rainy weather in spring.Contrarily,the cold and warm was less competitive in drought year,and the auxiliary area located in the central part of Mongolia,which was not conducive to the production of spring precipitation in Northern Shanxi.The analysis on the correlation of spring precipitation and abnormal air-sea presented there had more precipitation when the ENSO was in warm phase,and there had less precipitation when the ENSO was in cold phase in the spring of Northern Shanxi.The results were help to understand the origin of abnormal drought and flood in Northern Shanxi and provided a theoretical basis for shortterm climate forecast.