塔中一次强沙尘暴过程边界层风场变化特征

利用风廓线雷达探测资料对2010年4月19日塔中一次强沙尘暴过程中的边界层三维风场进行分析研究。沙尘暴爆发前,塔中1 000 m高度内空中风主导风向由偏东风转为偏西风;沙尘暴爆发时,地面至1 500 m高度内为偏东风。近地面风速在沙尘暴爆发初期迅速增大至18.3 m/s,中后期逐渐变小,但依然保持10 m/s左右的较大风速;300～1 000 m高度,沙尘暴爆发时段的风速小于过程前后;1 000～2 000 m高度内,沙尘暴爆发前风速达到最大,然后随时间变化呈递减趋势;3 000 m以上高空风在沙尘暴爆发期间风速可达20 m/s。沙尘暴过程中塔中上空存在明显的沙尘颗粒沉降运动,平均下沉速度为1.2 m/s。

The wind character of Boundary layer during sandstorm in TaZhong

The wind character of Boundary layer during sandstorm in TaZhong was given by using the wind profiler radar. The main results are given as follows: April 19 2010 in TaZhong, wind dirction changed from east to west below the 1000m altitude before the outbreak of the sandstorm. When the sandstorm occurs the wind direction was east below the 1500m altitude. Wind speed near ground increased rapidly during the forming of sandstorm. When the sandstorm occurs the wind speed decreaed. In the altitude range of 300m to 1000m the wind speed was lower during the sandstorm. In the altitude range of 1000m to 2000m the changes of wind speed was the same as near ground. Wind speed in above 3000m was as high as 20m/s during the sandstorms. There was a significant sedimentation of sand over the area during the sandstorms.