南京市霾天气与主要气象条件的相关分析

利用天气学原理,分析研究2012~2014年南京市霾天气的主要地面天气形势、气象要素以及PM2.5与PM10浓度的相互关系.结果表明,2012~2014年南京市霾天气以轻度和轻微霾为主,且冬季最多,夏季最少;相对湿度在50%~80%之间有利于霾的发生,尤其是70%≤RH<80%时;有87.6%的霾发生在风速≤4m/s的情况下,并且主要来自东北偏东到东南风向区域.最利于南京霾天气形成的主要天气形势是均压场、高压控制和高压后部,而低压槽、副高控制和台风影响时霾发生较少.PM2.5在PM10中所占比例与霾强度呈正比.通过对南京市气象条件与霾的关系,及后向轨迹HYSPLIT4模式的聚类分析显示,结合南京市霾天气时的风向统计,影响南京霾发生的污染源主要有本地源、南京市东南地区的近距离污染源和华北地区的远距离污染源.

The correlation analysis of Nanjing haze days and meteorological factors

In the present study, we discussed the interactions between surface weather types, ground weather situations, meteorological elements and the concentration of PM2.5 and PM10 in the haze days in Nanjing 2012~2014 by using synoptic meteorology principle. The results showed that most of the haze pollutions in Nanjing were slight and mild, mainly occurred in winter and seldom in the summer. The haze days occurred easily when the relative humidity between 50%~80%, especially 70%~80%. Nearly 87.6% of the haze days occurred in the case of wind speed 4m/s or less and wind direction northeast to southeast. The haze days frequently presented in the uniform pressure field, high pressure control, and the back of the high pressure, while in the conditions of under controlled by the subtropical high pressure, low pressure trough and typhoon, it was rare. The ratio of mass concentrations of PM2.5 in PM10 was proportional to the strength of haze pollutions. The results of trajectory clustering analysis by HYSPLIT4 mode showed that in the medium and heavy haze days in Nanjing, it was mainly affected by the local pollution and sources from northeast China and southeast of Nanjing.