甘肃酒泉地区近地层风场特征

Characteristics of Wind Field Near Ground Layer in Jiuquan of Gansu Province

利用酒泉地区4个测风塔(2009年10月至2010年9月)一年的近地层风场观测资料,对该地区近地层风场的月平均风速及方差、风场日变化特征、垂直变化、风向玫瑰、最大风速、风速威布尔分布、低空风切变等特征进行了分析。结果表明:酒泉地区一年中近地层平均风速最大出现在夏季或春季,对应的风向最多为东风或西风方向,最小出现在冬季;近地层平均风速具有上层风速夜晚大,白天小,中间存在一个日变化较小的转换层;近地层平均风速廓线,不论冬夏底层风速均随高度的增高而增大,且夜晚比白天增大得快。近地层风垂直切变8月份白天风速垂直切变较夜晚小,最靠近地面一层的风切变最大,存在一个风切变最小的中间层;冬季表现出和夏季不一致的特征。夏季近地层主频风向东风方向占多数,冬季近地层主频风向为东、西风方向占多数,存在较大季节差异。

Based on the data of wind field near ground layer from October 2009 to September 2010 observed by 4 wind towers in Jiuquan of Gansu Province, the characteristics of monthly average wind speed and its variance, daily variation of wind field, wind rose, maxi- mum wind speed, Weibull distribution of wind speed, low - level wind shear were analyzed. The results show that the maximum value of the average daily wind speed usually occurred in spring and summer, and their corresponding wind directions were mostly west and east, but the minimum value usually occurred in winter. The average wind speed over the upper ground layer was big at night and small in daytime. The mean wind profile near ground layer increased with height and it increased faster at night than that in daytime. In Au- gust, the vertical shear of the wind near ground layer was smaller in daytime than that in night, and the maximum value occurred on the layer being closest to the ground, while the smallest value occurred on the middle layer. In winter, the dominant wind directions were mostly east and west, while in summer the dominant wind directions were mostly east.