北京市秋冬季环流型下的细颗粒物传输

利用Models-3/CMAQ模式系统对北京市2013~2018年秋冬季（即当年11、12月和次年1、2月份）细颗粒物（PM_2.5）进行模拟，计算北京周边4个截面的PM_2.5传输通量，结合流场、浓度的分析，总结11种大气环流型下北京市的PM_2.5传输特征.污染严重的西南（SW）和西（W）环流型下，北京地区受强烈的PM_2.5传输作用，0.6km以下南部平原的输入产生了非常强的输入累积作用，加重了北京地区PM_2.5的污染程度.污染严重的南（S）环流型下，0.6km以下东部平原和0.6km以上南部平原的输入都产生了较强的输入累积作用，京津冀东部和南部地区的污染物通过不同高度范围传输影响北京地区的PM_2.5水平.污染同样严重的均压（UM）和气旋（C）环流型下，各方向的传输都没有产生明显的输入累积作用，本地排放的削减对于污染的控制尤为重要.污染中等的东（E）、东南（SE）环流型下，北京地区在近地层（0.2km以下）通过南部平原截面对保定等城市有较大的输出通量，对北京污染具有较强的输出消散作用.污染轻的北（N）、东北（NE）和西北（NW）环流型下，北京地区在1km以下通过东部平原截面对廊坊、天津等城市有很大的输出通量，对北京污染具有很强的输出消散作用.污染轻的A环流型下，北京地区没有明显的PM_2.5输入输出现象.

Fine particulate matter transport driven by circulation types in autumn and winter over Beijing area

Models-3/CMAQ was applied to simulate fine particulate matter (PM_2.5) during autumn and winter (Nov.-Feb., 2013~2018) in Beijing, and was used to calculate PM_2.5 transport flux on four cross sections around Beijing, which can combine with flow field and concentration to investigate PM_2.5 transport characteristics in 11 atmospheric circulation types in Beijing. In heavy polluted southwest (SW) and west (W) circulation types, PM_2.5 strong transport suffered Beijing, the input flux from the southern plain had very strong input accumulation effect below 0.6km, which increased the pollution level of PM_2.5 in Beijing. In heavy polluted south (S) circulation type, the input flux of the eastern plain below 0.6km and the input flux of the southern plain above 0.6km had strong input accumulation effect, so PM_2.5 transport from eastern and southern areas of Beijing-Tianjin-Hebei region in different altitude ranges affect PM_2.5 level in Beijing. In uniform pressure fields (UM) and cyclone (C) circulation types, transport in all directions had no obvious input accumulation effect, so the reduction of local emissions was particularly important for pollution control. In moderately polluted east (E) and southeast (SE) circulation types, Beijing had a large output flux below 0.2km to the northern cities such as Baoding through the southern plain section, which had strong output dissipation effect on Beijing pollution. In clean northern (N), northeast (NE) and northwest (NW) circulation types, Beijing had a very large output flux below 1km to the eastern cities such as Langfang and Tianjin through the eastern plain section, which had very strong output dissipation effect on Beijing pollution. In clean polluted anticyclone (A) circulation type, Beijing had no obvious PM_2.5 input and output phenomena.