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Effect of dust and anthropogenic aerosols on columnar aerosol optical properties over Darjeeling (2200 m asl), Eastern Himalayas, India

Chatterjee, A and Ghosh, SK and Adak, A and Singh, AK and Devara, PCS and Raha, S (2012) Effect of dust and anthropogenic aerosols on columnar aerosol optical properties over Darjeeling (2200 m asl), Eastern Himalayas, India. PLoS ONE, 7 (7). pp. 1-10.

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Abstract

Background: The loading of atmospheric particulate matter (aerosol) in the eastern Himalaya is mainly regulated by the locally generated anthropogenic aerosols from the biomass burning and by the aerosols transported from the distance sources. These different types of aerosol loading not only affect the aerosol chemistry but also produce consequent signature on the radiative properties of aerosol. Methodology/Principal Findings: An extensive study has been made to study the seasonal variations in aerosol components of fine and coarse mode aerosols and black carbon along with the simultaneous measurements of aerosol optical depth on clear sky days over Darjeeling, a high altitude station (2200 masl) at eastern Himalayas during the year 2008. We observed a heavy loading of fine mode dust component (Ca2+) during pre-monsoon (Apr - May) which was higher by 162 than its annual mean whereas during winter (Dec - Feb), the loading of anthropogenic aerosol components mainly from biomass burning (fine mode SO4 2- and black carbon) were higher (76 for black carbon and 96 for fine mode SO4 2-) from their annual means. These high increases in dust aerosols during pre-monsoon and anthropogenic aerosols during winter enhanced the aerosol optical depth by 25 and 40, respectively. We observed that for every 1 increase in anthropogenic aerosols, AOD increased by 0.55 during winter whereas for every 1 increase in dust aerosols, AOD increased by 0.46 during pre-monsoon. Conclusion/Significance: The natural dust transport process (during pre-monsoon) plays as important a role in the radiation effects as the anthropogenic biomass burning (during winter) and their differential effects (rate of increase of the AOD with that of the aerosol concentration) are also very similar. This should be taken into account in proper modeling of the atmospheric environment over eastern Himalayas.

Item Type: Article
Additional Information: Copyright: © 2012 Chatterjee et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Uncontrolled Keywords: black carbon, air analysis; article; atmospheric transport; chemical composition; concentration (parameters); dust exposure; India; particulate matter; physical chemistry; seasonal variation; winter, Aerosols; Air; Calcium; Dust; Environment; Humans; India; Optical Processes; Particulate Matter; Soot; Sulfates; Tropical Climate
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 07 Jun 2014 07:24
Last Modified: 07 Jun 2014 07:24
URI: http://moeseprints.incois.gov.in/id/eprint/471

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