Journal of Arid Meteorology

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Meteorological Condition of Explosive Increase and Maintaining of PM2.5 Concentration During Two Heavy Pollution Processes in Beijing

WU Jin 1,2, LI Chen3, SUN Zhaobin2, WANG Hua1, MA Xiaohui1   

  1. 1. Beijing-Tianjin-Hebei Prediction and Early Warning Center for Environmental Meteorology, Beijing 100089, China;
    2. Institute of Beijing Urban Meteorology (IUM), CMA, Beijing 100089, China;
    3. Beijing Meteorological Service Center, Beijing 100089, China
  • Online:2017-10-31 Published:2017-10-31

北京地区两次重污染过程中PM2.5浓度爆发性增长及维持的气象条件

吴进1,2,李琛3,孙兆彬2,王华1,马小会1   

  1. 1.京津冀环境气象预报预警中心,北京100089;2.中国气象局北京城市气象研究所,
    北京100089;3.北京市气象服务中心,北京100089
  • 作者简介:吴进(1984—),女,工程师,主要从事环境气象预报与服务工作. E-mail:wujin_0472@163.com。
  • 基金资助:

    2017年中国气象局预报员专项(CMAYBY2017-003)和国家级气象科研院所基本科研业务费(IUMKY201724)共同资助

Abstract:

Based on hourly PM2.5 concentration data observed at 80 environmental monitoring stations and meteorological observation data in the Beijing-Tianjin-Hebei region, meteorological conditions were analyzed for the fog and haze events during 16-21 December 2016 and 1-7 January 2017. The results show that the meteorological conditions were more favourable for accumulation and transport of pollutants. The PM2.5 concentration increased sharply in Beijing from 19 to 20 December 2016, which was mainly due to the strengthening of southerly wind in the boundary layer from the surface to 700 meters height, the low level weak sink inhibition and maintenance of the ground convergence. During 20-21 December 2016, weak warming occurred in the atmospheric boundary layer below 1.5 km, and the inversion layer thickened and enhanced and there was no obviously diurnal variation, which led to weak diurnal variation of the mixed layer thickness and aerosol concentration and thus high value and weak diurnal variation of PM2.5 concentration. On the whole, during 16-21 December 2016, the explosive growth of pollutant concentration was dominated by exogenous pollutants transport. And during 3-4 January 2017, the explosive growth of the pollutant concentration was due to the local extreme adverse weather conditions, which was not conducive to the diffusion of pollutants.

Key words: heavy pollution, explosive growth, southerly thickness of boundary layer, surface convergence line, inversion layer

摘要:

基于京津冀地区80个环境监测站PM2.5浓度逐时监测资料和气象观测资料,以2016年12月16—21日和2017年1月1—7日雾和霾天气为例,分析PM2.5浓度演变的气象条件。结果表明:气象条件在北京地区污染物浓度爆发性增长过程中具有重要作用。北京地区12月19—20日PM2.5浓度出现爆发性增长,小时浓度在8 h内上升201 μg·m-3,主要是边界层南风分量由地面增厚至700 m,700 m以上弱下沉抑制作用,结合地面辐合线维持所致;20—21日北京地区PM2.5浓度维持高值且无日变化,是由于低空1.5 km出现弱回暖,逆温层显著增厚增强且无明显日变化,导致高浓度气溶胶无法有效扩散。综合来看,2016年12月16—21日污染物浓度爆发性增长的原因以外源性污染物输送为主;2017年1月3—4日污染物浓度爆发性增长原因与局地极端不利扩散条件及污染排放等其他因素有关。

关键词: 重污染, 爆发性增长, 边界层南风分量厚度, 地面辐合线, 逆温层

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