敦煌地区沙尘天气特征分析

Characteristics Analysis of the Sand-dust Weather in Dunhuang Area

根据敦煌国家基准气候站1951年1月至2009年2月地面观测资料,利用要素时间演变序列分析了近60 a来敦煌沙尘天气的时间演变特征。分析表明,敦煌地区沙尘天气呈明显的递减趋势,20世纪50年代呈高发期,季、月差异显著,呈"单峰型"分布,春季最多,秋季最少。年大风日数减少,平均风速减小是敦煌沙尘天气减少的主要气象原因。并对形成敦煌沙尘天气的天气系统进行了环流分型。丰富的沙尘源和地域效应为敦煌沙尘天气的形成提供了必要的物质条件。

According to the data of ground - based observation from 1951 to 2008 at Dunhuang national standard climate station, the spatio - temporal change of sand - dust weather in Dunhuang area was analyzed. The result reveals that the sand - dust weather obviously decreased. It occurred most frequently in the 1950s, and in a year, it occurred most in spring and least in autumn. The annual wind days decrease and wind speed becoming small were the main reasons for sand - dust weather reduction in Dunhuang area. Meanwhile, the circulation causing sand - dust weather there was classifyed in the paper. Ample resources of sand - dust and regional effects provide essential material conditions for sand - dust weather occurrence.