Changes in wind activity from 1957 to 2011 and their possible influence on aeolian desertification in northern China

Abstract

Wind activity is proved to have significant impacts on aeolian desertification. Clarifying the fluctuations and change trend of wind velocity is important for understanding their influence on aeolian desertification. In this study, we used a dataset of wind velocities collected from 93 meteorological stations across northern China from 1957 to 2011 to analyze the changes in wind activity during this period. We tested the monotonic and step (abrupt) trends for annual and seasonal data of mean wind velocity by using Mann-Kendall and Mann-Whitney tests, respectively. The results indicated that the annual mean wind velocity decreased by 0.83 m/s from 1957 to 2011. The decreasing trends were also significant (P<0.01) for each season. The magnitude of the decrease was smallest in the east of northern China and largest in the west of northern China, and the most remarkable decrease occurred in the northwest of northern China. Abrupt decreases in annual and seasonal mean wind velocities occurred in the mid-1980s, which was consistent with the changes in aeolian desertification since the mid-1980s in northern China. As revealed by our study, although both modern aeolian desertification and ecosystem rehabilitation are affected by human activities to some extent, they are also likely to be strongly controlled by climate change, especially by wind activity.