大风对新疆沙尘暴的影响

Effects of Strong Winds on Sandstorms in Xinjiang

选取 1961— 1999年新疆 90个气象观测站的气表 1资料 ,对比分析了沙尘暴及大风的时空分布特征 ,探讨大风对沙尘暴发生的贡献及沙尘暴发生时的最多风向和最低风速指标。分析发现 ,新疆沙尘暴与大风的地理分布刚好相反 ,沙尘暴多的地区大风较少 ,但有着基本一致的气候变化趋势。大风对沙尘暴的贡献北疆大于南疆。沙尘暴发生时的最多风向明显指示出引发沙尘暴的天气系统来向。引起沙尘暴的最低风速指标 ,北疆及东疆超过 10m s ,南疆的吐鄯托盆地和焉耆盆地为 10m s ,塔里木盆地为 6～ 8m s ,盆地南缘只有 6m s。

With observational data spanning 1961—1999 from 90 meteorological stations in Xinjiang,the spatial and temporal characteristics of sandstorms and strong winds,and the contribution of strong winds to the occurrence of sandstorms are analyzed.Moreover,the dominant wind direction and minimum wind speeds during sandstorm periods are discussed.The research shows that although possessing similar climatic trends,sandstorms and strong winds in Xinjiang have opposite geographical distributions, i.e. places with more sandstorms show fewer strong winds.The contribution of strong winds to sandstorms in northern Xinjiang is larger than that in southern Xinjiang.The dominant wind directions clearly indicate the paths of the weather systems that introduced the sandstorms.The minimum wind speeds in the sandstorms were over 10?m/s in northern and eastern Xinjiang and in the Turpan and Yanqi Basins of southern Xinjiang.In Tarim Basin of southern Xinjiang,however,the minimum wind speed was about 6～8?m/s,and even 6?m/s at its southern edge.