【作者】 蔡霞； 梁桂花； 吴占华；

【Author】 Cai Xia;Liang Guihua;Wu ZHanhua;Shuozhou Meteorological Bureau;

【机构】 朔州市气象局；

【摘要】 利用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年夏季降水资料,对晋北夏季多雨、少雨年的大气环流异常特征进行了合成分析表明:多雨年夏季500h Pa位势高度中高纬度呈现出"正-负-正"的分布特征,乌拉尔山以东大区和鄂霍次克海是异常高压脊,而贝加尔湖和蒙古上空是一个异常低压槽,晋北地区处在槽的东南部,有利于降水偏多。相反少雨年中高纬度呈现"负-正-负"的分布,大陆地区出现两个异常槽和一个异常脊,晋北处于脊区的东南侧,在下沉气流控制下,导致降水偏少。对流层低层流场多雨年西太平洋有暖湿气流向北输送,直达蒙古到东北一带与西伯利亚分裂下来的弱冷空气在华北地区相遇,有利于夏季降水偏多。少雨年我国东部为较强的偏北气流,十分不利于西南水汽向北输送,导致降水偏少。通过分析晋北夏季降水与海温异常的关系得出:当前期ENSO暖位相时晋北地区夏季降水偏多,前期ENSO冷位相晋北地区夏季降水偏少。更多还原

【Abstract】 Based on NCEP reanalysis data,the ICOADS SST grid data and the observed data of summer precipitation from 18 meteorological stations in Northern Shanxi during 1960-2008,By composite analyzing the abnormal atmospheric circulation character of rainy and drier years in summer of Northern Shanxi,it showed that geopotential height anomaly in Europe and Asia had the effect on abnormal summer precipitation.The 500 h Pa geopotential height present a "positive-negative-positive" distribution characteristics in the summer of rainy years in Northern Shanxi.The east of the Ural Mountains and the sea of okhotsk had abnormal ridge,the Lake Baikal and Mongolia had abnormal trough.Northern Shanxi was in the southeast of the trough,it conducive to the rainfall.Contrarily,the geopotential height present a " negative-positive-negative " distribution characteristics in drought years.The mainland had two abnormal trough and one abnormal ridge.Northern Shanxi was in the southeast of the rige,sinking airflow lead to less precipitation.In rainy years,Tropospheric low laminar flow field the western Pacific had warm current to flow north through Mongolia to the northeast area,they met the weak cold air of Siberian division in north China,it conducive to rainfall in the summer of Northern Shanxi.In drought years,the stronger northerly air current in the east of China was not conducive to southwest vapor was transported to the north,It lead to less precipitation.The analysis the correlation of summer precipitation and abnormal air-sea showed that there would have more precipitation when the ENSO was in warm phase,and there would have less precipitation when the ENSO was in cold phase in the summer of Northern Shanxi.更多还原