行星边界层内扩散特征的一个数值研究

AN INVESTIGATION ON DIFFUSION CHARACTERISTICS IN THE PBL BY A NUMERICAL METHOD

中文摘要:

      使用近年来PBL内实测平均风,湍流统计量和拉氏时间尺度随高度变化的结果,对用最简单的二阶闭合假设导出的三维定常物质连续方程作数值解,分析讨论了风速、风向和湍流统计特征量的垂直切变以及粗糙长度z₀对PBL内浓度分布的影响。本文的结果对PBL内湍流扩散本质的认识及污染模式的建立均有益处。

英文摘要:

      Using the newly observed results of variation of mean wind, the turbulent statistics and Lagrangian time scales with height in the PBL, the stationarity three-dimensional equation of mass continuity which is gained by the secondorder closure assumption is solved by a numerical method. The influences of vertical shear of wind speed and the turbulent statistics, and of the roughness length on pollution concentrations in the PBL are analysed. The results are useful both in understanding the turbulent diffusion essence in the PBL and in establishing pollution models.