南京市一次持续性霾天气的多元分析

Multivariate Analysis of a Persistent Haze in Nanjing City

利用环保部的常规观测资料、WunderGround的地面观测资料和美国国家海洋和大气管理局(NOAA)的NCEP/NCAR的再分析资料,从PM2.5、环流形势、水汽条件、热力层结、垂直运动和温度平流等几个方面对2013年12月3-9日南京市的一次大范围持续性霾过程进行了分析。结果表明:稳定的环流形势,较低的风速是维持霾天气的重要因素;相对湿度的近地层直减率越高,近地层空气越潮湿越容易导致霾的发生;垂直上升运动减弱会抑制颗粒物向上扩散;温度平流较小、逆温层和均温层均利于近地面污染物的积累。后向轨迹模拟显示,此次霾过程,除了南京本地的污染源导致的污染物浓度上升外,北方冬季供暖产生的污染物的长距离输送也是本次南京市的霾天气形成的原因之一。

Based on the conventional observation data of the Ministry of Environmental Protection, ground observation data of Wunder Ground and the reanalysis data of NCEP/NCAR of National Oceanic and Atmospheric Administration(NOAA),PM2.5, circulation, water vapor condition, thermal stratification, vertical motion, temperature advection and other aspects of Nanjing from 3 rd to 9 th in December of 2013 are analyzed in the persistent haze process. The results show that the stable cir-culation and low wind speed are important factors to maintain the haze weather; high surface layer relative humidity lapse rate and the wet surface layer air more easily lead to the occurrence of haze; the decrease of vertical motion will inhibit particles spread upward; small temperature advection, the inversion temperature layer and uniform temperature layer are beneficial to the accumulation of pollutants in the near ground. Backward trajectory simulation shows that apart from the increase of pollu-tant concentration caused by local pollution sources in Nanjing City, the long distance transportation of the pollutants pro-duced by heating in the north of China is also one of the reasons for the formation of the haze weather in Nanjing City.