1960-2017年黄土高原地区风速时空变化特征

Spatiotemporal Variability of Wind Speed in the Loess Plateau During 1960-2017

[目的]揭示黄土高原地区风速时空变化特征,为区域防灾减灾提供参考。[方法]基于黄土高原59个气象站1960—2017年逐月风速实测数据,采用线性回归、Mann-Kendall检验和滑动t检验等方法,对黄土高原地区历年及四季风速的时空变化趋势进行了研究。[结果](1)1960—2017年黄土高原年均风速以-0.0075 m/(s·a)速率显著下降,春季降幅最大,其次为冬、秋季,夏季降幅最小;年内月平均风速先升后降,4月风速下降最快,7月下降最慢。(2)黄土高原历年及夏、秋、冬季风速均在1980s突变减少,春季平均风速未发生突变,冬季风速突变后较突变前降幅最大,秋季最小。(3)黄土高原历年均风速、历年及四季风速变率均表现出西北高、东南低的特征,站点呈下降趋势的春季最多,夏季最少。(4)AO指数的上升、气候变暖及地表植被覆盖增加等,可能不同程度地造成黄土高原风速长期下降趋势。[结论]黄土高原区应将春季作为防风御风重点时段,将西北部地区作为重点防御地区,增强防灾减灾能力建设。

[Objective]The aim of this study is to explore the temporal and spatial variation characteristics of wind speed in the Loess Plateau,and then provide reference for regional disaster prevention and mitigation.[Methods]Based on the measured monthly wind speed data of 59 meteorological stations in the Loess Plateau during 1960 to 2017,the temporal and spatial variation trend of wind speed over annual and four seasons in the Loess Plateau was studied by using linear regression,Mann-Kendall test and sliding t-test,etc.[Results](1)The annual average wind speed in the Loess Plateau decreased significantly at the rate of-0.0075 m/(s·a),with the largest decline in spring,followed by winter and autumn,with the smallest decline in summer.The monthly average wind speed showed a tendency of increasing first but decreasing afterwards,with the fastest decline in April and the slowest decline in July.(2)The wind speed of annual average,summer,autumn and winter decreased abruptly in 1980s,and the average wind speed in spring did not change abruptly.After the abrupt change,the average wind speed declined the fastest in winter and the slowest in autumn.(3)The spatial distribution of the average wind speed and the change rate of annual and seasonal wind speed showed the characteristics of high in the northwest and low in the southeast.Meteorological stations with decline of wind speed were the most in spring,and the least in summer.(4)The rise of AO index,climate warming and the increase of surface vegetation cover might lead to the long-term downward trend of wind speed in the Loess Plateau.[Conclusion]In the Loess Plateau,spring should be taken as the key period in terms of wind prevention,and the northwest should be taken as the key prevention area in which the construction of disaster prevention and mitigation capacity should be strengthened.