大气成分与大气化学  

Atmospheric Composition and Atmosphere Chemistry

出　　处：《中国气象科学研究院年报》2018年第1期96-138,共43页Annual Report of Cams

摘　　要：大气成分与大气化学研究进展1大气成分及相关特性变化观测研究1.1基于地面激光雷达比较2016/2017年冬季东北地区2次大气污染事件本研究分析和比较了2016年12月19-22日(E1事件)和25-26日(E2事件)中国东北地区2次大气污染物的气溶胶特性和气象条件。通过2016年12月至2017年1月在辽宁省沈阳市地区的激光雷达测量的气溶胶消光系数和退偏比,并结合行星边界层(PBL)分析了该地区的能见度、颗粒物(PM)的质量浓度和地面气象要素。结果表明,在E1事件中,低的PBL高度会导致污染物的不容易扩散,而高的PBL会伴随低的能见度,其可能原因是污染物浓度在大气中的垂直输送和跨区域的高空水平输送。在E1事件中,当PBL高度增加时,PM的质量浓度下降,而在E2事件中,却恰恰相反,2个变量呈正相关。在E2事件中,当风比较强的时候,会导致污染物加速扩散,并在一定程度上促进了气溶胶的运输。在E1事件中,当大气中有强烈的逆温层存在时,会导致PM2.5和PM10的浓度增加,且E1事件中沈阳周边地区的气溶胶主要来自华北平原向西南地区的污染物输送。在E1事件中,由于当地环境近地面污染物浓度大且PBL低导致该地区消光系数较大。然而在E2事件中,当PBL高的时候,气溶胶的跨区域运输以及地面附近的低PM质量浓度则与高海拔地区气溶胶浓度较大的消光有关。这些结果可能有助于更好地了解中国东北冬季污染事件中气溶胶特性的垂直分布。Progress in Research on Atmospheric Composition and Atmospheric Chemistry 1 Observational studies of atmospheric composition and related properties 1.1 Analysis of typical air pollution episodes in winter 2016 using ground-based LIDAR over Northeast China This study analysed two pollution events in a period of high pollution in 2016, in Shenyang, China: episode 1 (19–22 December) and episode 2 (25–26 December). The visibility, particulate matter (PM) mass concentration, and meteorological data from surface observations, the planetary boundary layer (PBL), the aerosol vertical profile including aerosol extinction coefficient and volume depolarisation ratio, were measured using the ground-based LIDAR from December 2016 to January 2017. The results suggested that the lower PBL height led to poor pollution dilution in episode 1, while the higher PBL height accompanied by lower visibility in episode 2 might have been due to intense air vertical transportation. Strong wind could diffuse the pollutants via turbulence and make a large contribution to the vertical transportation of aerosols. The correlations of PM2.5, PM10, SO2, CO, NO2, and O3 with the PBL height were approximately .0.54,.0.51,.0.40,.0.45,.0.46, and 0.52, respectively. The strong temperature inversion on 19 December 2016 resulted in increased PM2.5 and PM10 concentrations, and the wind speed and direction on 25 December 2016, and favoured the south-westerly transportation of aerosols from the North China Plain. The extinction coefficient in episode 1 contributed to local pollution under the lower boundary layer with higher ground-surface PM mass concentrations, while the severe aerosol extinction event at high altitudes was defined by cross-regional transport with a higher boundary layer and lower PM mass concentrations near the ground. The time–height volume depolarisation ratio at 532 nm was not higher during the polluted period, which suggested that dust was not the main cause of the high extinction coefficient. The results of this study help us

关 键 词：大气化学 大气成分 中国东北地区 地面气象要素 气溶胶浓度 大气污染物 激光雷达比 污染物浓度 

分 类 号：P402[天文地球—大气物理学与大气环境]