南疆一次强沙尘暴的近地层特征和湍流输送分析

利用2006年4月10日沙尘暴过境期间塔克拉玛干沙漠腹地80 m垂直梯度探测系统的实时资料,分析了该地区近地面层气象要素和湍流输送特征的变化过程。结果表明,沙尘暴过境期间,近地层风速有先降低后增大的过程,10 m高度上动量向下输送明显,热量输送只有很小的上传趋势；沙尘暴过境前,近地面为弱稳定的逆温层,空气处于暖干的状态,10 m高度上垂直气流表现为系统性的下沉运动,随着沙尘暴爆发,湍流交换显著增强,空气进入相对冷湿状态,气流有上升运动趋势,但强度不大,仍以水平湍能为主。

Surface Layer Characteristics and Turbulent Flux Transfer during a Strong Sandstorm in South Xinjiang

Using real-time data obtained from 80 meters grads sounding system during a strong sandstorm process from April 9 to 11 of 2006 in hinterland of Taklimakan Desert,the authors analyzed characteristics of meteorological elements and turbulent flux transfer in surface layer during the sandstorm process.Results were as following.While the sandstorm broke out,wind speed was very slow at first and then increased sharply,and there were downward momentum transfer flux and upward heat transfer at the 10-m height above the surface layer.Before the dust storm broke out,there was weakly stable inversion layer in near surface,the flows were warm-dry with low pressure,and systemic downward flows occurred at the height of 10-m.When the dust storm broke out,flows became wet-cold with high pressure,and turbulence exchange increased sharply,and there were weakly upward flows,but turbulent kinetic energy was larger in horizontal direction than in vertical direction.