不同天气条件下近地层风速脉动特征

Wind Speed Fluctuation near the Ground Surface over the Hinterland of the Taklimakan Desert under Different Weathers

利用塔克拉玛干沙漠腹地-塔中地区的风速、风向观测资料,分析晴天、沙尘暴和扬沙天气条件下不同高度平均风速、风速脉动和风向脉动特征,探讨沙尘天气对近地层风速和风向脉动的影响。结果表明:①3种天气条件下,地表0. 5 m以上各高度层的脉动风速具有较好的相关性,且相邻高度脉动风速的相关性更加显著,相关系数均大于0. 68;脉动风速的波动范围与高度呈正比例关系。②随着高度的增加,沙尘暴和扬沙天气条件下的风速脉动强度呈增大趋势,而晴天时则是先增大后减小;风速脉动强度在沙尘暴天气时最大,扬沙天气次之,晴天最小;不同天气条件下2 m高度范围内风速脉动强度的增长速度大于2～10 m高度。③不同天气条件下风向脉动幅度均较小,且基本不随高度的改变而变化。

This study was based on the field observation and meteorological data at Tazhong in the Taklimakan Desert. The purposes of the study were to investigate the characteristics of wind velocity fluctuation over the quicksand surface in the desert hinterland,analyze the average wind speed and wind direction fluctuation on sunny day,in sandstorm and under blowing sand weather,and lucubrate the effects of sandstorm on the wind speed and wind direction fluctuation near the ground surface. The results are as follows:(1) There was a good correlation of wind speed fluctuation at different heights higher than 0. 5 m from the ground surface,especially there was a significant correlation of wind speed between the adjacent heights,and the correlation coefficient was higher than 0. 68. The wind speed fluctuation range was proportional to the height;(2) With the increase of height from the ground surface,the intensity of wind speed fluctuation was in an increase trend in sandstorm and under blowing sand weather,but it was increased at first and then decreased on sunny day. The increase of wind speed fluctuation intensity within 2-m height was higher than that at height range of 2-10 m under different weather conditions;(3) The wind direction fluctuation under different weather conditions was low and did not basically change with the height.