川西高原近地面风速时空变化特征及影响因素

Temporal and spatial variation characteristics and influencing factors of wind speed near the surface of the Western Sichuan Plateau

风是主要的气象因子,随着空气污染的日益严重,分析风速变化对研究区域环境及气候有重要意义.基于川西高原15个站点平均风速资料,利用线性趋势分析与Morlet小波变换,分析了川西高原近地面风速变化特征及其与气象因素的联系.结果表明:(1)川西高原多年平均风速为1.95 m/s,并以-0.087 (m/s·10a)的速率呈波动下降趋势;四季风速呈现冬、春风速大,夏、秋风速小,春季风速大于夏、秋风速下降趋势的特征.(2)受环流、季风和地势等因素影响,风速在空间上呈西北、东南地区风速大,中部地区风速小的特征,且冬季和春季空间分布相似.(3)风速存在多尺度周期变化特征,其中主周期48 a变化最明显.(4)风速与气温、气压呈显著的负相关和正相关关系,且气压对风速的影响大于气温.

Wind is the main meteorological factor. With the ever increase of air pollution, the analysis of wind speed change is of great significance to the study of regional environment and climate. Based on the average wind speed data of 15 stations in the Western Sichuan Plateau, the variation characteristics of near-surface wind speed over the Western Sichuan Plateau and its relationship with meteorological factors were analyzed by use of linear trend analysis and Morlet wavelet transform. The results show that:(1)The annual mean wind speed over the Western Sichuan Plateau is 1.95m/s, and it fluctuates and decreases with a rate of-0.087(m/s/10a). The seasonal wind speed showed the characteristics of "high wind speed in winter and spring, low wind speed in summer and autumn", and "the decreasing trend of wind speed in spring was greater than that in summer and autumn".(2)Due to the influence of circulation, monsoon and topography, the wind speed is found to be high in northwest and southeast regions and low in central regions. The spatial distribution of wind speed is similar in winter and spring.(3) the wind speed has the characteristics of multi-scale periodic variation, and the oscillation energy of the main period is the largest at 48a.(4)Wind speed has a significantly negative and positive correlation with air temperature and pressure, and air pressure has a greater impact on wind speed than air temperature.