新疆夏季变湿的大气环流异常特征  

Atmospheric Circulation Anomalies during Wetting Summer over Xinjiang Region

作　　者：赵兵科[1] 蔡承侠 杨莲梅[3] 王慧 

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室 [2]新疆环境气象中心,新疆乌鲁木齐830002 [3]中国气象局乌鲁木齐沙漠气象研究所,新疆乌鲁木齐830002

出　　处：《冰川冻土》2006年第3期434-442,共9页Journal of Glaciology and Geocryology

基　　金：新疆自治区自然科学基金项目(200421102);中国气象局沙漠研究基金项目(20040108)资助

摘　　要：利用1961—2003年NCEP／NCAR再分析资料和中国气象局整编的新疆夏季（6～8月）月降水量资料，分析了新疆夏季1971—1986年干旱期和1987—2003年湿润期的大气环流变化异常特征。结果表明：在平均环流场上，中亚-巴尔喀什湖槽及上下游地区脊的增强是新疆地区夏季变湿的环流场特征之一，且中亚-巴尔喀什湖槽随高度增加强度明显增强，200 hPa达到最强；源于低纬阿拉伯海向北直至中亚对流层低层偏南的强气流是湿润期环流异常、降水增多的又一特征，也是水汽重要来源之一；中亚上空高空急流轴南压是新疆夏季湿润期与干旱期高空急流最重要的差异特征。Based on NCEP/NCAR reanalysis of monthly mean data set from 1961 to 2003 and summer precipitation data set from 16 observation stations of Xinjiang Region reorganized by China Meteorological Administration, the atmospheric circulation anomalies are examined in summer for the dry spell from 1971 to 1986 and the wet spell from 1987 to 2003. The main results are as following： 1） The prominent changes of atmospheric circulation took place in summer from the dry spell to the wet spell in Xinjiang Region, including remarkably strengthening of the polar vortex and the ridge of Mongolia in low- and middle troposphere, and evidently intensifying of the ridge from Li sea to Ural mountain and the trough between the middle Asian region and Balkash Lake in upper level. 2） The main differences on the stream field from the dry spell to the wet spell in Xinjiang Region include a strong air flow from Arabian Sea to middle Asian in the low troposphere and a thick cyclonic circulation in the middle Asian region from the middle- to upper troposohere. 3） The primary difference of vertical meridional circulation in summer from the dry spell to the wet spell in Xinjiang Region is the fact that the updraft in the western of Xinjiang Region intensifies remarkably. This is one of the favorable conditions for increasing precipitation of summer in Xinjiang Region. 4） In summer, from the dry spell to the wet spell in Xinjiang Region, the larger region of strengthening notably of moisture and relative humidity is the same as of increasing of the southerly. Thus, there is a southwest-northeast channel for enhancing moisture transfer from low- to middle latitude, which, likely, is one of the favorable conditions for increasing the precipitation of summer in Xinjiang Region. In addition, moistening in Xinjiang Region is not only in the lower level but also in the all troposphere. 5） The opposite change of intensities of north and south of the upper level jet streak in the west of Xinjiang Region between the wet and dry spells, in

关 键 词：新疆夏季变湿 大气环流异常 中亚-巴尔喀什湖槽 蒙古高压脊 

分 类 号：P434[天文地球—大气科学及气象学]