title: A temperature inversion-induced air pollution process as analyzed from Mie LiDAR data.
abstract: A severe air pollution event in the Xianlin District of Nanjing City, China during 23-24 December 2012 was analyzed in terms of aerosol extinction coefficient and AOT retrieved from Mie scattering LiDAR data, in conjunction with in situ particulate concentrations measured near the Earth's surface, and the Weather Research Forecast-derived meteorological conditions. Comprehensive analyses of temperature, humidity, wind direction and velocity, and barometric pressure led to the conclusion that this pollution event was caused by advection inversion. In the absence of temperature inversion, the atmosphere at a height of 0.15 km has a relatively large extinction coefficient. In situ measured particulates exhibited a very large diurnal range. However, under the influence of turbulences, AOT was rather stable with a value <0.2 at an altitude below 0.8 km. Advection inversion appeared at 9:00 AM on 24 December, and did not dissipate until 22:00 PM. This temperature inversion, to some degree, inhibited the dispersion of near-surface particulates. Affected by this temperature inversion, the atmospheric extinction coefficient near the surface became noticeably larger. Near-surface particulates hardly varied at a concentration around 0.2mg/m(3). AOT at an altitude below 0.8 km rose to 0.31.
authors.affiliation: Key Laboratory of Virtual Geographic Environment, Ministry of Education, College of Geographic Science, Nanjing Normal University, Nanjing 210097, China.
authors.forename: Wanning
authors.initials: W
authors.lastname: Wu
authors.affiliation: Key Laboratory of Virtual Geographic Environment, Ministry of Education, College of Geographic Science, Nanjing Normal University, Nanjing 210097, China. Electronic address: yzha@njnu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zha
authors.affiliation: Lab. of Digital Earth Sciences, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China. Electronic address: hzhang@ceode.ac.cn.
authors.forename: Jiahua
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Environment, University of Auckland, Auckland 1008, New Zealand.
authors.forename: Jay
authors.initials: J
authors.lastname: Gao
authors.affiliation: Key Laboratory of Virtual Geographic Environment, Ministry of Education, College of Geographic Science, Nanjing Normal University, Nanjing 210097, China; Department of Resources and Environment, Shijiazhuang University, Shijiazhuang 050035, China.
authors.forename: Junliang
authors.initials: J
authors.lastname: He
mesh_terms: D000336:Aerosols / Q000032:analysis; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D000531:Altitude; D001272:Atmosphere / Q000737:chemistry*; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D058998:Remote Sensing Technology; D063809:Satellite Imagery; D013696:Temperature; D014887:Weather
chemical_list: D000336:Aerosols; D000393:Air Pollutants
keywords: Aerosol; Air pollution; LiDAR; Particulate matter; Temperature inversion