河西走廊沙尘暴50a频率突变检测分析

Research of Abrupt Changes of Sandstorm Frequency in Hexi Corridor in Recent 50 Years

利用1958年至2007年民勤、敦煌、武威、张掖、景泰的沙尘暴春季发生频次资料,运用滑动t检验和滑动F检验进行突变检测分析,根据检验结果综合确定突变点及其突变强度,寻求沙尘暴发生频率突变规律及产生原因,为沙尘暴发生频率的变化趋势研究和预测提供参考。滑动t检测结果显示,5站点的沙尘暴春季频率突变数量呈现往东部递增的趋势;降低突变较多;升高突变年份集中在20世纪60年代末期和90年代末期,降低突变主要出现在1983年及2002年前后;均值降低突变强度大于升高突变。滑动F检验结果显示突变均是方差降低突变;河西走廊中东部的沙尘频率波动性差异较其他地区更为显著;方差突变出现在80年代中期及90年代初期,其余时间的波动性的差异维持在一个较低的水平。当对沙尘暴发生频率进行滑动t及滑动F检验时,两种情况下的降低突变检测结果存在一定的对应关系。河西走廊地区的沙尘暴发生频率突变与地面风速、大风日数、降水量及平均气温的突变存在密切联系,可作为沙尘暴频率突变的预测因子。

Based on data of dust storm frequency of spring in Dunhuang,Minqin,Wuwei,Zhangye and Jingtai in Hexi Corridor from 1958 to 2007,sliding t Test and sliding F Test were used to search for possible abrupt changes in the mean value and get the intensity and reason of abrupt changes.The sliding t test of abrupt changes in the mean value indicated that abrupt change frequency showed an increasing trend from the west to the east,so Jingtai got the highest abrupt change frequency;the frequency of abrupt decreasing change is larger than that of abrupt increasing change;the abrupt increasing changes concentrated in the late 1960s and the late 1990s;the abrupt decreasing changes were found around 1983 and 2002;the intensity of abrupt increasing changes was higher than the abrupt decreasing changes.The sliding F test of abrupt changes indicated that the central-eastern Hexi Corridor has the much more significant variation than other regions;the abrupt changes are mostly found in the middle 1980s and the early 1990s,and the volatility is not significant in other periods.There is some correlation between the abrupt decreasing changes test results of the frequency of dust storms in spring by sliding t Test and sliding F Test.The abrupt changes of dust storm frequency in Hexi Corridor were closely linked with abrupt changes of surface wind speed,windy days,precipitation and average temperature,so they can be used for forecasting the abrupt changes of dust storm frequency.