北京边界层外来污染物输送通道

由京、津、冀气候站历史资料及激光雷达资料分析,在稳定天气条件下,北京市外来污染物各类尺度的输入通道流场分为边界层西南气流、东南气流和东风气流风带型,其中对形成北京输送汇风带的统计表明,西南风带汇发生频率占45%,东南风带汇占36%,东风风带汇占19%。输送通道是指空间和时间稳定性风带,是区域尺度、局地尺度的范围内相继出现的欧拉风场,且有多频率发生的特征。按城市间尺度流型可分为城市间东风、西南风、东南风输送通道。具有一定空间尺度和时间尺度的相继性、接续性输送特征,按配置的天气系统可分为大陆高压南部偏东风输送通道系统、海上高压后部东南风输送通道系统、河套倒槽前西南风输送通道系统、东北低槽前部偏南风输送通道系统等。3个风带流经地区恰好位于华北平原3个主要排放源群地区。 

Transport Pathways of Pollutants from Outside in Atmosphere Boundary Layer

By analyzing the historic data of Beijing, Tianjin and Hebei climatology stations, it was found that under stable weather conditions, the transport pathways of outside pollutants were divided into the southwest current, southeast current and east current, and the statistic data of the wind belts of the transport convergence (TC) showed that the TC of the southwest wind belt took 45 percent of all belts, the rate of the southeast wind belt was 36 percent, and that of the east wind belt 19 percent. The transport pathways (TPs) referred to the stable wind belts in the space and time scale, and the Euler wind field which appeared in secession in the territorial scales and local scales, being characterized by high frequency. On the intercity scales the current types could be divided into the TPs of the east wind, southwest wind and southeast wind, which were characterized by succession and continuance. On the dispose of the weather system, the current types could be divided into the TP system of the near east wind in the south wind of the territorial high pressure, the TP system of the southeast wind on the back of the high pressure on the sea, the TP system of the southwest wind in front of the inverse trough of the Great Bend of the Yellow River, and the TP system of the south wind in front of the low trough of the northeast, etc. All the three wind belt areas were right situated in the regions of three major emission sources of the plain of North China.