关键词: 滑动t检验, 滑动F检验, 沙尘暴, 突变

Abstract: 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.

Key words: sliding t test, sliding F test, sand storm, abrupt change