Springer Science + Business Media;Berlin/Heidelberg: Springer-Verlag
摘要:
摘要： We analysed aerosol optical and physical properties in an urban environment (Kolkata) during winter monsoon pollution transport from nearby and far-off regions. Prevailing meteorological conditions, viz. low temperature and wind speed, and a strong downdraft of air mass, indicated weak dispersion and inhibition of vertical mixing of aerosols. Spectral features of WinMon aerosol optical depth (AOD) showed larger variability (0.68–1.13) in monthly mean AOD at short-wavelength (SW) channels (0.34–0.5 μm) compared to that (0.28–0.37) at long-wavelength (LW) channels (0.87–1.02 μm), thereby indicating sensitivity of WinMon AOD to fine aerosol constituents and the predominant contribution from fine aerosol constituents to WinMon AOD. WinMon AOD at 0.5 μm (AOD ₀. ₅) and Angstrom parameter ( α) were 0.68–0.82 and 1.14–1.32, respectively, with their highest value in December. Consistent with inference from spectral features of AOD, surface aerosol loading was primarily constituted of fine aerosols (size 0.23–3 μm) which was 60–70 % of aerosol 10- μm (size 0.23–10 μm) concentration. Three distinct modes of aerosol distribution were obtained, with the highest WinMon concentration at a mass median diameter (MMD) of 0.3 μm during December, thereby indicating characteristics of primary contribution related to anthropogenic pollutants that were inferred to be mostly due to contribution from air mass originating in nearby region having predominant emissions from biofuel and fossil fuel combustion. A relatively higher contribution from aerosols in the upper atmospheric layers than at the surface to WinMon AOD was inferred during February compared to other months and was attributed to predominant contribution from open burning emissions arising from nearby and far-off regions. A comparison of ground-based measurements with Moderate Resolution Imaging Spectroradiometer (MODIS) data showed an underestimation of MODIS AOD and α values for most of the days. Discrepancy in relative distribution of fine and coarse mode of MODIS AOD was also inferred. 其他題名： Environ Sci Pollut Res 其他題名： Environ Sci Pollut Res Int 出版者： Berlin/Heidelberg: Springer-Verlag 出版日期： 2014-04-01 出處： Environmental Science and Pollution Research, 2014-04, Vol.21 (7), p.4977-4994 資源來源： ABI/INFORM Collection 版權： Springer-Verlag Berlin Heidelberg 2013 版權： Springer-Verlag Berlin Heidelberg 2014 識別號： ISSN: 0944-1344 識別號： ISSN: 1614-7499 識別號： EISSN: 1614-7499 識別號： DOI: 10.1007/s11356-013-2383-5 識別號： PMID: 24363049
