以敦煌黑山嘴沙漠绿洲过渡带为例,利用可移动梯度风测量系统,获取晴天和沙尘暴天气过程中沙漠绿洲过渡带近地表风速脉动特征,研究沙尘天气对近地表风速脉动影响。结果表明:无论晴天或沙尘暴,相同测点各高度层脉动风速具有很好的相关性,相邻高度脉动风速的相关性更加显著,脉动风速的波动范围与高度和风速呈正比。沿沙漠至绿洲方向,晴天环境下脉动强度先增大后减小,沙尘暴环境下脉动强度逐渐减小。沙尘暴和晴天环境下脉动风速的变化规律相近,但沙尘暴环境下风向相关性更加显著,风速脉动强度更大。风速与脉动强度呈正相关,沙尘对脉动强度产生一定抑制作用。
The wind speed fluctuation characteristics of the desert-oasis ecotone in Heishanzui area of Dunhuang was studied using a portable gradient wind measurement system during sunny and duststorm weather processes. The results show that wind speed fluctuations at different heights have good correlation in both sunny days and duststorm processes in the same observation point, and more significant correlation occurs in the adjacent height. The wind speed fluctuation range increases with increasing height. Meanwhile, the fluctuation intensity of wind speed first increases then decreases along the direction from desert to oasis during sunny days, while it continuously decreases during sandstorm processes. Wind speed fluctuation rule in sunny days is similar to that in a duststorm processes. However, the correlation of wind directions in the same measuring point is more significant during duststorm processes compared with that in sunny days, and the wind speed fluctuation intensity is larger. Besides, wind speed is positively related to the fluctuation intensity, and the duststorm has certain inhibitory effect on strength of the fluctuation intensity.
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