• 关键词：霾天气  烟花爆竹  沙尘  秸秆燃烧  不利气象条件

• 基金项目：公益性气象行业专项(No.GYHY20120611);国家重点基础研究发展计划(No.2011CB403406,2014CB441203)

• 傅瑜
• 南京大学 大气科学学院, 南京 210093

• 王体健
• 南京大学 大气科学学院, 南京 210093

• 黄晓娴
• 南京大学 大气科学学院, 南京 210093

• 廖镜彪
• 南京大学 大气科学学院, 南京 210093

• 朱佳雷
• 南京大学 大气科学学院, 南京 210093

• 摘要：利用2011年南京大学城市大气环境观测站气象因子及污染物浓度资料、58238站点气象探空资料及NCEP再分析资料、CALIPSO卫星资料,比较分析了南京地区4类典型霾天气(烟花爆竹、沙尘、秸秆燃烧及不利气象条件污染)的污染特征.结果表明:烟花爆竹个例污染物排放集中,以细颗粒物为主,除夕和初五的PM_2.5小时浓度分别达到0.46 mg·m^-3和0.34 mg·m^-3,受逆温层影响,能见度持续降低,最低达到1.16 km;受北方沙尘暴南下影响,沙尘个例以粗颗粒为主要污染物,PM₁₀小时最高浓度为0.78 mg·m^-3,PM_2.5/PM₁₀平均值为0.39,粒子形状不规则,体积偏退比为0.17;秸秆燃烧个例为重霾污染,能见度最低值为0.97 km,后向散射系数为0.0039 km^-1·sr^-1,PM₁₀和PM_2.5最高小时浓度达到0.80 mg·m^-3和0.49 mg·m^-3,颗粒物主要来自南京东南地区秸秆的集中燃烧;不利气象条件导致的污染过程在冬季比较常见,下沉气流活跃,出现双层逆温,近地面静小风造成污染物积累,PM_2.5与能见度的相关系数达到0.86,细颗粒物为主要污染物.可见,南京市霾天气可分为两类,分别是由不利气象条件导致的累积性污染和由高强度排放源造成的暴发性污染,具有不同的气象和污染特征.

• Abstract：Four typical haze episodes caused by firework, dust storm, biomass burning, and adverse meteorological conditions in Nanjing were selected and analyzed based on meteorological factors and pollutant concentrations observed from Nanjing University Urban Atmospheric Environment Observation Station, sounding data of site 58238, NCEP reanalysis data and CALIPSO satellite observations. The results showed that particulate matters during the firework case were mainly caused by emissions and fine particulate matters were the majority. Hour concentrations of PM_2.5 during the Eve and the fifth day of the Chinese New Year reached 0.46 mg · m^-3 and 0.34 mg · m^-3 respectively. Affected by temperature inversion, visibility decreased continuously reaching minimum of 1.16 km. The coarse particulate matters played important role in the episode of dust storm from the North. Maximum hourly concentration of PM₁₀ reached 0.78 mg · m^-3 and average value of PM_2.5/PM₁₀ was only 0.39. The shape of particle matters was irregular and the volume depolarization ratio was 0.17. The episode caused by biomass burning was characterized by low visibility of 0.97 km and backscattering of coefficient 0.0039 km^-1 · sr^-1. The highest hourly concentration of PM₁₀ and PM_2.5 were 0.80 mg · m^-3 and 0.49 mg · m^-3 respectively. Particulate matters were mainly from biomass burning at the southeast region of Nanjing. The episode caused by adverse meteorological condition usually occurred in winter, in which the downdraft was strong with double layer inversions. The accumulation of pollutants was caused by weak and calm wind near the ground surface. The correlation coefficient of PM_2.5 and visibility was up to 0.86. In summary, haze episodes in Nanjing can be divided into two categories, one is the cumulative pollution caused by adverse weather conditions, the other is outbreak pollution caused by high-intensity emissions. The two typical haze episodes show different characteristics on meteorology condition and pollution level.

• Key words：haze episode  firework  dust storm  biomass burning  adverse meteorological condition

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