title: Column-integrated aerosol optical properties and direct radiative forcing over the urban-industrial megacity Nanjing in the Yangtze River Delta, China.
abstract: Aerosol optical properties were measured and analyzed through the ground-based remote sensing Aerosol Robotic Network (AERONET) over an urban-industrial site, Nanjing (32.21° N, 118.72° E, and 62 m above sea level), in the Yangtze River Delta, China, during September 2007-August 2008. The annual averaged values of aerosol optical depth (AOD500) and the Ångström exponent (AE440-870) were measured to be 0.94 ± 0.52 and 1.10 ± 0.21, respectively. The seasonal averaged values of AOD500 (AE440-870) were noticed to be high in summer (autumn) and low in autumn (spring). The characterization of aerosol types showed the dominance of mixed type followed by the biomass burning and urban-industrial type of aerosol at Nanjing. Subsequently, the curvature (a 2) obtained from the second-order polynomial fit and the second derivative of AE (α') were also analyzed to understand the dominant aerosol type. The single scattering albedo at 440 nm (SSA440) varied from 0.88 to 0.93 with relatively lower (higher) values during the summer (spring), suggesting an increase in black carbon and mineral dust (desert dust) aerosols of absorbing (scattering) nature. The averaged monthly and seasonal evolutions of shortwave (0.3-4.0 μm) direct aerosol radiative forcing (DARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and bottom of atmosphere (SUR) during the study period. Further, the aerosol forcing efficiency (AFE) and the corresponding atmospheric heating rates (AHR) were also estimated from the forcing within the atmosphere (ATM). The derived DARF values, therefore, produced a warming effect within the atmosphere due to strong absorption of solar radiation.
authors.affiliation: Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/International Joint Laboratory on Climate and Environmental Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China.
authors.forename: Na
authors.initials: N
authors.lastname: Kang
authors.affiliation: Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/International Joint Laboratory on Climate and Environmental Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China. kanike.kumar@gmail.com.
authors.forename: K Raghavendra
authors.initials: KR
authors.lastname: Kumar
authors.affiliation: Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/International Joint Laboratory on Climate and Environmental Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China.
authors.forename: Xingna
authors.initials: X
authors.lastname: Yu
authors.affiliation: Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/International Joint Laboratory on Climate and Environmental Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, Jiangsu, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yin
mesh_terms: D000336:Aerosols / Q000032:analysis; D002681:China; D004391:Dust / Q000032:analysis; D045483:Rivers / Q000737:chemistry*
chemical_list: D000336:Aerosols; D004391:Dust
keywords: AERONET; Aerosol optical depth; Aerosol type; Nanjing; Radiative forcing; Single scattering albedo