塔里木盆地南缘策勒典型下垫面水的湍流特征

Turbulent characteristics of horizontal wind over typical underlying surfaces in Cele at the southern rim of Tarim Basin

基于2010年3月28日天气过程在策勒地区实测风速数据,分析戈壁、绿洲农田、灌木林三种典型下垫面3 m高度水平风速的最大脉动风速、湍流强度、阵风因子等湍流特征,结果显示:(1)近地层湍流在时间序列上具有多尺度复杂性,湍流强度、阵风因子均随分析时距增大呈对数增长;(2)以10 min为分析时距获得的各项参数都显示绿洲植被显著降低了同等高度风速的水平分量,同时也引起了湍流强度和阵风因子的显著增强,并导致了最大脉动风速的大幅度提升;(3)本次实测风速段内最大脉动风速与平均风速成正相关关系,且戈壁、绿洲农田、灌木阻沙林随风速的增长速率依次增大。

At the southern rim of the Tarim Basin,sand-wind hazard is severe and affect the local people seriously,especially the agricultural production.To understand the turbulent characteristics of horizontal wind near ground surface layer,an experiment was conducted in Cele at the southern rim of the Tarim Basin.In the experiment,wind speed at height of 3 m was observed over three typical underlying surfaces(Gobi,farmland and shelterbelt) and then a weather process was obtained during March 28th 2010.In the paper,the turbulent characteristics of the observed horizontal wind,including maximum fluctuation wind speed,turbulence intensity and gust factors,were analyzed for the three typical underlying surfaces.The results show that: turbulence in the surface layer has obvious complexity at multiple time scales,and the turbulence intensity and gust factors have logarithmic relationships with the analyzed time scales;the differences of the analyzed parameters per 10 min.among the three underlying surfaces indicates that the oasis vegetation reduces the horizontal wind at the same height significantly while increased the turbulence intensity and gust factor and ascends the maximum fluctuation wind speed greatly;the maximum fluctuation wind speed correlates with the corresponding average wind speed positively,and the increased rates of the maximum fluctuation wind speed with the average wind speed are as follows: shelterbelt's > farmland's> Gobi's.The results provide reference values for studies on turbulent characteristics of horizontal wind and offer theoretical guidance for sand-wind control at the southern rim of the Tarim Basin.