Analysis of Surface Wind Field Characteristics in the Last 25 Years in Xinjiang,China

In addition to be impacted by large-scale atmosphere circulation,the surface wind is also influenced by regional terrain.In Xinjiang,there are large basins,big mountains and canyons,so surface wind field is special there.In this paper,based on Xinjiang surface wind field data from 1980 to 2004,long-term surface wind field characteristics of this region are analyzed,and the empirical orthogonal function decomposition to the data is made.Results show that there are significant differences between surface wind field in northern,eastern and southern Xinjiang,especially in wind direction changes: northwest wind for northern Xinjiang,east wind for southern Xinjiang,airflow conversion of anticyclonic from northwest wind to east wind for eastern Xinjiang.Analysis of long-term change of meridional wind in Xinjiang shows that the meridional wind is manifested in increase of southerly wind anomalies,while the zonal wind is manifested in weakening of westerly wind anomalies.Meridional wind change has 3—5 years short-term change cycle in the whole time series,and zonal wind change has 3—6 years cycle,and they all show a phenomenon of continuation of their cycles growth over the time lengthen.The maximum value of the meridional southerly wind anomalies occurs at Qijiaojing,while the maximum value of meridional northerly wind anomalies occurs at Alashankou.The maximum value of zonal wind westerly wind anomalies is also at Qijiaojing,while the maximum value of zonal easterly wind anomalies is at Andehe.EOF analysis shows that the variance contribution of the first mode is 87.5%,while the anomaly values of temporal coefficient of the first mode showed "positive-negative-positive" trend.