中文摘要：

应用天气研究与预报（weatherresearchandforecasting，WRF）模式以及三维拉格朗日轨迹模式，以北京2003年10月18—22日出现一次重污染过程为例，研究反气旋系统控制下污染物的输送规律和移动路径，并分析环境和气象观测数据，阐述其成因．结果表明，当反气旋均压控制北京地区时，由于地方性环流起主导作用，污染物在反气旋控制区内徘徊，形成地方性风输送积累；当反气旋后部偏南风经过北京地区时，本地区累积的污染物向东北输送，最终在低压区汇聚垂直抬升，进入自由大气．

英文摘要：

Based on a Lagrangian particle dispersion model FLEXPART 3-D in conjunction with a weather research and forecasting （WRF） model, this study investigates the mechanism and trajectory of pollutants under the anti-cyclonic weather system that took place during October 18-22, 2003 in Beijing. The reasons for this heavy air pollution episode were also analyzed by using the environmental and meteorological observational data. The findings indicate that pollutants hovered in Beijing by local wind under the control of anticyclone, the accumulated pollutants was transported to the northeast during the back of anticyclone, and the pollutants finally converged to the low-pressure area and elevated to free atmosphere.