利用风廓线雷达资料对广州地区边界层日变化特征的分析研究

DIURNAL VARIATION OF ATMOSPHERIC BOUNDARY LAYER OVER WUSHAN STATION, GUANGZHOU USING WIND PROFILER RADAR

利用2010年11—12月亚运会期间设在广州五山站的车载式边界层风廓线雷达资料,对广州地区晴天条件下的边界层日变化特征进行分析。结论表明:(1)折射率结构常数具有明显的日变化特征。夜间,受大气层结的抑制作用,湍流强度较弱,折射率结构常数的观测值约为10-17～10-18m-2/3;白天,湍流在热力作用和动力作用的共同影响下,从底层大气向自由大气发展,观测值比夜间可增大两个量级,且在边界层顶部有较大阶跃。(2)利用风廓线雷达谱宽资料可算出湍流耗散率,作为一种新的风廓线雷达二次产品,该参数对湍流的描述更为准确和细致。在晴天条件下,广州地区边界层顶从08时开始迅速上升,11时前后达到1 300 m左右,在日落前基本维持这个高度不变。

This paper analyzes the diurnal variation of the atmospheric boundary layer over Wushan station, Guangzhou by using data from a wind profiler radar （WPR）. The results are shown as follows. （1） The structural parameter of turbulence reflectivity has significant diurnal variation characteristics. During the night, because of the bottom of the atmosphere presenting a stable stratification, the turbulence intensity becomes weak and the observed values of the parameter is about 10-17- 10-18 m-2/3. During the daytime, under the influence of the thermodynamic and dynamic effect, the movement of turbulence becomes more active. The increasing of the observed value is about 2 orders of magnitude as much. In addition, the observed value shows great change at the top of the boundary layer. （2） The dissipation rate of turbulent kinetic energy, used as a new product of WPR, can be calculated using the WPR data. This parameter displays the accurate and fine structure of turbulence. In the Guangzhou area, under the condition of clear sky, the top of the boundary layer begins growing rapidly at 08：00, reaches 1 300 m at 11：00, and remains at this altitude until sunset.