关键词: 最大风速, 分布特征, EOF空间分布, 重现期

Abstract: As one of the strongest sources of the sand storm in the north，it is very important to study the regional maximum wind speed. Depending on the data of 5 basic stations recorded from 1971 to 2013 and 35 regional stations recorded from 2009 to 2013，and then rebuilding the complete database for these stations by using the regression method，according to the Mann - Kendall examination，EOF empirical orthogonal function，the Gumbel distribution and so on，the change of maximum wind speed characteristics was studied. The studies have shown that in 1971-2013，the region’s maximum wind speed reduced obviously especially in Minqin County，Gansu Province，China（0.187 9 m·s^-1·a^-1）. There are 3 extremum centers on the distribution of the maximum wind speed: one is the northern desert region represented by Hongshagang Station，the second is the western beaches represented by Hongshanyao Station，the last is the Qilian Mountains represented by Wushaoling Station，these 3 stations have obvious advantages in max wind speed observation so that they become the study area for the main characteristics of wind field. Selecting Hongshagang，Hongshayao，Fengle and Wushaoling as the representative stations，the paper found that the maximum wind speed decline rate in the first three stations are 0.173，0.104，0.103，but the change is not obvious in Wushaoling，and the decline rate changes just around the average value. Month maximum wind speed appears in unimodal distribution，the maximum is more likely to appear in February to June，especially in April and May，accounted for 34.8%-56.8% year，but there are still some differences between each station. Using EOF empirical orthogonal function  to analyze the maximum wind speed，the cumulative contribution value of the first feature vectors is as high as 95.23%. Starting from the first eigenvector of eigenvalues to analyze the risk characteristics，the paper found that the northern desert areas and Qilian Mountains are typical risk areas， needs to take strict precautions against with. Using the Gumbel distribution to figure out the return period of the maximum wind speed，according to the results，the study area can be divided into different areas，the maximum wind speed in the next 10 years，30 years，50 years，and 100 years in the northern desert are 29.18，30.20，30.82 and 31.63 m·s-1，showing that this area is a typical wind damage zone. In this paper，the regional station data are used to analyze the characteristics of maximum wind speed and these conclusions can be used for studying regional development strategies and projecting design.

Key words: maximum wind speed, distribution characteristics, EOF spatial distribution, return period