南京冬季大气气溶胶粒子谱分布及其对能见度的影响  

Size Distributions of Aerosol Particles and the Impact on Visibility in Winter of Nanjing

作　　者：尚倩[1] 李子华[1] 杨军[1] 濮梅娟[2] 

机构地区：[1]南京信息工程大学大气物理与大气环境重点实验室,南京210044 [2]江苏省气象局,南京210008

出　　处：《环境科学》2011年第9期2750-2760,共11页Environmental Science

基　　金：国家自然科学基金项目(40975085);公益性行业(气象)科研专项(GYHY200906012);江苏省重大科技支撑与自主创新示范工程项目(BE2008618)

摘　　要：2009年11～12月采用宽范围气溶胶粒径谱仪(WPS)、自动气象站和能见度仪等高分辨率仪器对南京北郊气溶胶粒子的谱分布特征与气象因子的关系及其对大气能见度的影响进行研究.结果表明,数浓度谱呈双峰分布,主峰集中在0.04～0.1μm;质量浓度谱的2个主峰位于0.5～0.7μm和2.7μm左右;表面积谱的2个主峰分别位于0.1～0.5μm和0.5～0.9μm之间.气溶胶浓度存在明显的日变化和日际变化,日变化主要与人类活动及大气边界层状况有关,而日际变化主要受降水、风、相对湿度等气象条件的影响;粒子数浓度分布受相对湿度(RH)的影响较显著,当RH<54%时,随着RH增大,直径<1μm的粒子数浓度增加,而直径>1μm的粒子数浓度几乎无变化,当相对湿度>54%时,随着RH增大,0.01～0.2μm和2.7～10μm范围内粒子数浓度降低,0.5～1.5μm之间的粒子数浓度明显增加;雨、雾、晴和灰霾天气状态下气溶胶粒子谱分布各异,雨天各尺度档数浓度与晴天相比都有减少,雾天0.01～0.3μm和2.7～10μm范围的气溶胶粒子数浓度比晴天低,而0.3～2.7μm之间的粒子数浓度高于晴天,降雨和浓雾对粗粒子的清除作用依次比核模态和积聚态粒子大;灰霾天气溶胶粒子谱的峰值略向大粒径方向偏移,0.03～0.1μm之间的粒子数浓度比晴天低,而0.1～2.7μm范围内粒子数浓度高于晴天;根据Mie理论,对能见度和不同粒径段气溶胶粒子的表面积浓度进行相关性分析,发现0.1～2μm之间的粒子表面积浓度与能见度相关性较好,是导致南京地区能见度降低的主要因素.High resolution instruments were used to investigate the relationship between aerosol size distribution characteristics and meteorological factors,and its possible influence on visibility in urban Nanjing from November to December 2009.Results show that the size distribution of aerosol number concentration showed a bimodal shape with the main peak value concentrating at particle sizes of 0.04-0.1 μm.Mass concentration distribution presented a bimodal shape with the two peak values concentrating at particle sizes of 0.5-0.7 μm and 2.7 μm,and the surface area concentration distribution presented two peaks from 0.1 to 0.5μm and from 0.5 to 0.9μm.It is found that the diurnal and interdiurnal variations of particle concentrations are obvious.Human activities and variation of atmospheric stability had great effect on daily variation of particle concentrations,while meteorological conditions such as precipitation,wind,relative humidity and so on had strong influence on interdiurnal variation.The aerosol size distribution was significantly affected by relative humidity.When RH was lower than 54%,number concentration of aerosol particles less than 1 μm in diameter increased gradually as RH increased,and concentration of particles with diameter larger than 1 μm almost had no change.When RH was higher than 54%,number concentration of aerosol particles ranging from 0.01 to 0.2 μm and from 2.7 to 10 μm decreased with the increase of RH,in contrast,concentration of aerosol particles between 0.5 and 1.5 μm in diameter increased.In addition,the particle number size distributions were different in rainy,foggy,sunny and haze weather conditions.Compared to sunny day,concentration of particles with different sizes all decreased in rainy day.In foggy weather,The number concentration of aerosol particles ranging from 0.01 to 0.3 μm and from 2.7 to 10 μm decreased,and aerosol particles between 0.3 and 2.7 μm increased in comparison with sunny day.Scavenging action of rain and fog to particles of different sizes from high t

关 键 词：气溶胶粒子 尺度谱 气象因子 能见度 南京 

分 类 号：X513[环境科学与工程—环境工程]