承德市近50年沙尘灾害时空分布特征及成因分析

Analysis of spatiotemporal distribution characteristics and formation causes of duststorm hazard in Chengde City in recent 50 years

基于1960-2009年承德市9个气象站的气象数据资料,探讨了承德市风沙灾害的时空分布特征。研究发现:沙尘灾害在承德市的空间差异十分明显,3种沙尘天气的发生日数以丰宁县最多,扬沙日数多年平均达到3.85次/a;3种沙尘灾害发生的空间分布除了整体上呈现由西北到东南递减趋势外,均有一个突出的舌形等值线。这条等值线基本上沿着"丰宁—滦平—承德县"向东南方向延伸,正好与滦河河谷的走向基本一致;从近20年沙尘天气发生的时间分布来看,2000-2002年是近20年来沙尘灾害最为集中和强烈的时期;从月际尺度而言,沙尘天气的发生呈现出"双峰一谷"型的变化,每年以3-5月沙尘天气发生的频次最多,冬季有一个沙尘天气次多期。

Based on the meteorological data during 1960-2009 of nine stations in Chengde City,the temporal and spatial distribution of sandstorms of Chengde City was explored.The study showed that the spatial difference of the dust hazard in Chengde City is very obvious.The occurrence days of the three types of duststorm weather is the most in Fengning County,and the average blowing dust weather days reach 3.85 times /a over years.In addition to an overall decreasing trend from northwest to southeast,the spatial distribution of the three kinds of dust disasters has a prominent tongue-shaped contour.This contour is basically along the ＂Fengning-Luanping-Chengde County＂,and extends to southeast direction,which coincides with the trend of the Ruanhe River valley.In view of temporal distribution of dust weather,the period from 2000 to 2002 is the years with most concentric and severe dust disasters.In view of monthly dimension,the duststorm weather most frequently occurs during March to May and has a second frequent period in winter.