甘肃省陇东地区近55年风速时空变化特征

Temporal and spatial variations of wind speed in Longdong of Gansu Province in recent 55 years

基于陇东地区3个国家气象站点(环县、崆峒、西峰)1960—2014年逐月平均风速、日最大风速、平均气温等数据,运用相关分析、Mann-Kendall突变检验以及小波分析等方法对陇东地区近55年风速时空变化特征及其影响因素进行分析。结果表明:1960—2014年陇东地区的年平均风速呈下降趋势,其变化倾向率为-0.09 m·s-1·10 a-1,其中1973—1984年平均风速在波动中呈快速减少趋势,而1995年之后进入平稳波动期,1960s的平均风速最大,1980s的平均风速最小;日最大风速和4级以上风速出现频次的快速减少对年平均风速的变化影响显著;四季平均风速均呈下降趋势,春冬两季的下降趋势最为显著,春季风速的波动趋势对其他3个季节风速的波动变化具有一定的预示性;平均风速最大的春季和平均风速最小的秋季与年平均风速波动变化的相关程度最为显著;3个站点年平均风速均呈减少趋势,其减少速度沿环县-西峰-崆峒的方向递减,各站点四季平均风速变化具有相同的规律;陇东地区年平均风速存在26年的第一主周期,并于1973年左右发生突变,其中,环县站发生突变的时间最早,崆峒站突变时间最晚;陇东地区年平均风速与年平均气温呈显著负相关,增温速度最快的春季和冬季,其风速的减小速度也是四季中最大的。

Based on the monthly average wind speed, maximum wind speed, average temperature data of three meteorological stations （Huanxian, Kongtong, Xifeng） in Longdong of Gansu from 1960 to 2014, the temporal and spatial variation characteristics of the wind speed and its influencing factors in Longdong was analyzed by using correlation analysis, Mann-Kendall mutation test and wavelet analysis methods. The results showed that the annual average wind speed had decreased by -0.09 m·s-1·10a-1 from 1960 to 2014, and had rapidly decreased during the period of 1973 to 1984, while entered a stable period of volatility after 1995 in Longdong. The average wind speed was the maximum in the 1960s, and it was the minimum in the 1980s. The rapid decreases of the daily maximum wind speed and the frequency of wind speed over grade 4 made great contributions to the decreased annual average wind speed. The seasonal average wind speed decreased at all three stations, and such trend was the most significant in spring and winter. The fluctuation of wind speed in spring played a predictable role in the fluctuation of wind speed in the other three seasons. The seasonal wind speed in spring （maximum） and autumn （minimum） played a most significant role in annual average wind speed. The average wind speed all decreased at all three stations, and the decreasing speed was gradually decreased from Huanxian, to Xifeng, and to Kongdong. The annual average wind speed had a first main cycle of 26 years, and it began to mutate in 1973. Huanxian and Kongtong were the earliest and the latest station of mutation respectively. The annual average wind speed was negatively correlated with the annual average temperature. The fastest warming occurred in spring and winter, and the reduction of wind speed in these two seasons was also the maximal among the four seasons.