风廓线雷达对塔克拉玛干沙漠晴天边界层的探测分析

利用塔克拉玛干沙漠大气环境观测试验站2010年8和10月边界层风廓线雷达资料,分析了沙漠晴天边界层湍流、大气温度、水平风速风向以及垂直速度的发展演变特征和日变化规律。研究表明：（1）大气折射率结构常数（C_n~2）能较好地反映晴空湍流对电磁波的后向散射能力,可以详细刻画湍流发展旺盛区域的高度、强度及其演变特征;沙漠夏季白天湍流发展剧烈,旺盛区域顶部可达4000 m高度左右。（2）RASS系统对沙漠边界层大气温度的探测具有较好的可信度,其近地边界层温度符合一般的日变化规律,昼夜温差显著,白天高温维持时间长,升温过程相对滞后于近地表气温。（3）风廓线雷达对大气风场的探测结果与地面风速风向一致,沙漠晴天主要受东风和东北风控制,风速较小,平均在2.0～6.0 m·s~（-1）范围变化。（4）沙漠腹地大气垂直速度变化符合静力平衡理论,铅直方向运动很弱,一般在-1.0～1.0 m·s~（-1）范围波动。

Radar Wind Profiler Observations of Convective Boundary Layer During Clear Air Days over Taklimakan Desert

The Urumqi Institute of Desert Meteorology under the China Meteorological Administration（CMA） launched a scientific experiment with the radar wind profiler at the Tazhong Station—an experimental site for atmospheric environment observations in the hinterland of the Taklimakan Desert in July—October 2010.This study uses high temporal resolution data from the experiment to analyze the turbulence development of boundary layer, vertical velocity and atmospheric virtual temperature of typical clear-air day.The results show that:（1） The turbulence refractive index structure constant（C_n²） can reflect in detail the development of turbulence,and the height of turbulence development bloom area in summer days may be reached at 4000 m.（2） RASS system has good credibility for atmospheric virtual temperature detection,and its near boundary layer is generally in line with the daily temperature variation.（3） The clear-air days in Taklimakan Desert are mainly controlled by east and northeast winds,the wind speed is relatively small and changes within 2.0—6.0 m·s^-1.The atmospheric vertical velocity change of the desert hinterland fits in with the static equilibrium theory,the vertical velocity is very weak, generally in the -1.0 to 1.0 m·s^-1 range fluctuations.