Optical properties and CCN activity of aerosols in a high-altitude Himalayan environment: Results from RAWEX-GVAX

Gogoi, Mukunda M and Babu, Suresh S and Jayachandran, V and Moorthy, Krishna K and Satheesh, SK and Naja, Manish and Kotamarthi, VR (2015) Optical properties and CCN activity of aerosols in a high-altitude Himalayan environment: Results from RAWEX-GVAX. In: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 120 (6). pp. 2453-2469.

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Abstract

The seasonality and mutual dependence of aerosol optical properties and cloud condensation nuclei (CCN) activity under varying meteorological conditions at the high-altitude Nainital site (2km) in the Indo-Gangetic Plains were examined using nearly year-round measurements (June 2011 to March 2012) at the Atmospheric Radiation Measurement mobile facility as part of the Regional Aerosol Warming Experiment-Ganges Valley Aerosol Experiment of the Indian Space Research Organization and the U.S. Department of Energy. The results from collocated measurements provided enhanced aerosol scattering and absorption coefficients, CCN concentrations, and total condensation nuclei concentrations during the dry autumn and winter months. The CCN concentration (at a supersaturation of 0.46) was higher during the periods of high aerosol absorption (single scattering albedo (SSA)<0.80) than during the periods of high aerosol scattering (SSA>0.85), indicating that the aerosol composition seasonally changes and influences the CCN activity. The monthly mean CCN activation ratio (at a supersaturation of 0.46) was highest (>0.7) in late autumn (November); this finding is attributed to the contribution of biomass-burning aerosols to CCN formation at high supersaturation conditions.

Item Type:	Journal Article
Publication:	JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Publisher:	AMER GEOPHYSICAL UNION
Additional Information:	Copy right for this article belongs to the AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA
Keywords:	aerosol; scattering coefficient; absorption coefficient; cloud condensation nuclei
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	22 May 2015 07:45
Last Modified:	22 May 2015 07:45
URI:	http://eprints.iisc.ac.in/id/eprint/51573

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