夏季区域极涡异常对塔里木河流域降水的影响  

Impacts of the Regional North Polar Vortex Anomalies on Summer Precipitation of the Tarim River Basin

作　　者：李红军[1,2] 马玉芬 Li Hongjun Ma Yufen(Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002 Center for Central Asian Atmosphere Science Research, Urumqi 830002)

机构地区：[1]中国气象局乌鲁木齐沙漠气象研究所,乌鲁木齐830002 [2]中亚大气科学研究中心,乌鲁木齐830002

出　　处：《应用气象学报》2017年第5期589-599,共11页Journal of Applied Meteorological Science

基　　金：国家自然科学基金联合基金项目(U1503181);气象公益院所专项(idm201603)

摘　　要：采用1961-2015年夏季大西洋-欧洲极涡面积指数和塔里木河流域43个站降水资料,研究该区域极涡面积异常对该流域降水的影响。结果表明:两者年际变化呈显著的反位相关系;在极涡面积异常偏小(大)年,西风急流在西亚和中亚减弱(增强),在东亚则相反;500 hPa欧洲中部和贝加尔湖地区的高压脊偏强(偏弱),东亚低压槽偏弱(偏强),中亚经向环流增强(减弱);700 hPa塔里木河流域天气扰动活跃(不活跃),东风和西南风(西北风)的水汽输送增强,西部和北部等主要降水区水汽辐合(辐散),该流域降水偏多(偏少)。在极涡面积异常偏小年的夏季,塔里木河流域水平风场和垂直运动从高纬度到低纬度的经向变化分布与大西洋-欧洲区相似,大西洋-欧洲极涡区与塔里木河流域之间存在西北-东南的环流异常分布,大西洋-欧洲极涡面积异常可能通过该环流异常分布影响塔里木河流域及周边风场、水汽输送和垂直运动,进而影响到该流域降水。With precipitation data of 43 stations in the Tarim River Basin and the polar vortex areas data in the Atlantic--European （polar vortex） in summer of 1961--2015, variation characteristics of the precipitation and the polar vortex, the correlation and impacts of north polar vortex anomaly on precipitation in the Basin are studied. The precipitation in the Basin has been increasing since 1961, while the polar vortex is decreasing, and a significant negative correlation is found. In negative （positive） polar vortex anomaly years, in the upper atmosphere layer, the significantly weaker （stronger） subtropical westerly jet in West Asia and Central Asia, while it is the opposite in East Asia （35°-45°N, 120°--160°E） and the Basin, where the high-middle latitude cold air and mid-low latitude warm wet air that enter the Tarim River Basin increase （decrease） and strengthen （weaken）. In the middle layer, negative （positive） polar vortex anomaly may lead to stronger （weaker） Middle European ridge and the Baike Lake ridge, weaker （stronger） East Asia trough, increased （decreased） meridional circulation in the Central Asian, and converging （diverging） stream in this basin. In the low layer, negative （positive） polar vortex anomaly may lead to stronger （weaker） anomaly easterly and southwesterly （northwesterly and northeasterly）, stronger （weaker） weather disturbance. More east vapor flux is found entering the Basin comparing to the west vapor flux outflowing away this Basin. Moreover, the southern and eastern vapor flux converging in the southwest borders, and the convergence of vapor flux are strengthened （weakened） in the main precipitation areas of the Basin, which all lead to the increasing （decreasing） of precipitation in the Tarim River Basin. In summer, the polar vortex anomalies in the Atlantic--European have impacts on the meridional wind, zonal wind and the vertical motion from the high latitude to the low latitude by the meridional corre- lation

关 键 词：大西洋-欧洲极涡 塔里木河流域降水 大气环流异常 

分 类 号：P461[天文地球—大气科学及气象学]