利用塔克拉玛干沙漠2次沙尘暴天气条件下人工绿地近地层80 m风速观测资料,探讨近地层风速脉动特征及其与能见度、PM10,PM2.5的关系,为进一步研究湍流情况下风蚀和风扬粉尘释放奠定基础。结果 表明:(1)不同高度风速脉动值在随高度的变化上近似符合高斯分布且在时间序列上波动性均具有一致性,脉动频率不稳定,无明显周期性,相邻高度间均具有显著相关性。(2)风速脉动强度随风速增大而增强,随距离地表高度的降低呈先增大后降低的趋势。湍流度均与高度成反比关系,整体上均随着高度的降低而增大,因为地表植被的存在增大了湍流度。(3)沙尘暴过程中地面风速的大小对水平能见度,PM10,PM2.5具有直接影响,风速脉动变化与水平能见度呈现反比关系,与PM10,PM2.5呈现正比关系。
Basing on the observation data of 80 m wind speed in the near-surface layer during two sandstorms in the constructed green land of Taklimakan Desert, the characteristics of wind pulsation in the near-surface layer and its relationship with visibility, PM10 and PM2.5 under sandstorm weather are discussed. It lays the foundation for further research on wind erosion and potential sand blowing in turbulent conditions. The results show that:(1)the pulsation values of wind speeds at different heights are approximately Gaussian distribution with the change of height, and the volatility is consistent in time series; the pulsation frequency is unstable and no obvious periodicity, and there is significant correlation between adjacent heights;(2)the fluctuation intensity is increasing with the increase of wind speed, and increases at first and then decreases with the decrease of the height of the surface; the turbulence is inversely proportional to the height, and the overall increases with the decrease of the height, because the bottom layer is increased by the presence of surface vegetation;(3)the magnitude of ground wind speed in sandstorm process has a direct impact on horizontal visibility, PM10 and PM2.5. Wind speed pulsation changes are inversely related to horizontal visibility, and are proportional to PM10 and PM2.5.
