摘要
针对2013年1月江苏淮安地区发生的一次连续性雾霾天气过程,分析该天气过程中PM10和PM2.5的质量浓度演变特征、能见度与气象要素之间的关系、中低层环流特征以及污染物来源。结果表明:雾霾期间PM10和PM2.5质量浓度最低值出现在05:00至07:00(北京时间,下同)和13:00至17:00,最高值出现在21:00至23:00,PM10和PM2.5质量浓度并非同时达到极大值;持续变化较小的气压梯度、较低的风速、相对湿度的增大以及PM2.5和PM10质量浓度的增高是雾霾发生发展的必要条件;能见度与气压、相对湿度、PM2.5质量浓度的相关性较好,建立回归方程,对能见度的整体变化趋势拟合效果较好;高空环流形势平稳、中低层的暖平流、持续稳定少动的地面高压场分布为雾霾天气的持续发生发展提供了有利的形势背景;稳定的层结结构、中低层偏东及偏东北方向气团的输送、本地污染源以及严重的空气污染是此次过程中能见度偏低、霾天数较多的主要原因。
Recently,the continuously high incidence of fog and haze events has been a topic of considerable concern among the public,since such events can bring serious harm in terms of the health and daily lives of the masses. A rare fog and haze event,which was wide-ranging,long-lasting and heavily polluting,occurred during 12—17 January 2013 in the Huai'an area of Jiangsu Province. In particular,the visibility of most of the area during 13—14January was lower than 0. 1 km,which is extremely rare. The event caused considerable disruption to expressways,air transport and sea transportation. In this study,in order to reveal the formation mechanism of regional and successional fog and haze,and to provide scientific evidence for forecasting and prediction and air pollution abatement,this event was chosen as a case of typical heavy fog and haze for the analysis of pollution variation and its characteristics. The variation characteristics of PM10 and PM2. 5,the relationship between visibility and meteorological variables,the circulation features at middle-lowlevels,and the pollution sources were explored based on the pollutant particle concentration,FNL data,conventional meteorological data,and Global Data Assimilation System data.The results indicated that the minimum value of hourly average PM10 and PM2. 5concentrations during this fog and haze event occurred at 0500—0700 BST and 1300—1700 BST,while the maximum value occurred at2100—2300. For PM10 and PM2. 5,the maximum concentrations appeared at different times. The increase inrelative humidity and the increase of PM2. 5and PM10 concentrations in total pollutant particles were the leading cause of visibility variation and persistent pollution. Several conditions,such as the slight variations inpressure gradient,sudden increase inrelative humidity,relatively lowwind speed,and the increase in PM10 and PM2. 5,were the main reasons for the rapid development of the fog and haze event. A good co-relationship between visibility and pressure,relative humidity,and PM2. 5concentration was observed. The overall variation trend of visibility could be well fitted by the regression equation.The representativeness of these results was analyzed and verified based on long-termsample data. The stable upper-air circulation situation,the warm advection at middle-lowlevels,and the stable ground pressure field provided abeneficial circulation situation for the development of the fog and haze event. During the event,varying levels of the thermal inversion layer werefound at lower layers. The deepthermal inversion layer and east wind near the surface layer wereconducivetothe lowvisibility and its wide distribution. The stable stratification structure,east-northeast air mass at the inversion layer and middle-lowlevels,local-source pollution and serious air pollution weremainly attributed to the relatively lowvisibility and longevity of the haze. The air quality was dependent on the concentration of pollutants.Meteorologists should identify meteorological indicesthatareadverse to the diffusion and dilution of pollutants when meteorological conditions that are adverse to pollutant diffusion appear. Early forecasting and timely warningsareessential for the prevention and treatment of air pollution.
出处
《大气科学学报》
CSCD
北大核心
2016年第2期243-252,共10页
Transactions of Atmospheric Sciences
基金
国家自然科学基金资助项目(41575135
41340042
40975085)
江苏省气象局青年基金(Q201409)
江苏省气象局预报员专项(JSYBY201305)
江苏省气象服务中心自立课题
关键词
雾
霾
能见度
气团轨迹
fog
haze
visibility
air mass trajectory