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Volume 15, No. 3, June 2015, Pages 985-993 PDF(1.96 MB)  
doi: 10.4209/aaqr.2014.07.0143   

A New Classification of Aerosol Sources and Types as Measured over Jaipur, India

Sunita Verma1, Divya Prakash1, Philippe Ricaud2, Swagata Payra1,2,3, Jean-Luc Attié2,3, Manish Soni1

1 Centre of Excellence in Climatology, Birla Institute of Technology Mesra, Jaipur Campus, Jaipur 302017, Rajasthan, India
2 CNRM GAME, Météo-France, CNRS UMR3589, Toulouse, France
3 Laboratoire d'Aérologie, Université de Toulouse, CNRS UMR5560, Toulouse, France

 

Highlights
  • First time aerosols types are classified over Jaipur, Northwestern India.
  • Novel approach of Aerosol Optical Thickness and Angstrom Coefficient is utilized.
  • Comparison of aerosols optical behavior with four more AERONET stations in India
  • Aerosols over Jaipur are more scattering in nature than other stations of India.
  • The absorption is least in summer and most in winter over the study area.

Abstract

 

The aerosol properties retrieved from the AErosol RObotic NETwork (AERONET) measurements during the period 2009 to 2012 over Jaipur (26.9°N, 75.8°E, 450m asl) in Northwestern India are used for the first time to identify the types of aerosols. In order to consider the appropriate threshold of aerosol optical thickness (τ) at 500 nm (τ500) and Angstrom exponent (α) in the spectral band 440–870 nm, a novel approach has been conducted and applied for the identification process. Five prevailing aerosol classes are identified: desert dust, biomass, maritime, arid background and mixed aerosols. Arid background and desert dust type aerosols are the most common at Jaipur (34.7% and 13.6%, respectively), with a wide variability in both τ and α. In about 8.4% of the cases, aerosols can be classified as maritime, although mixing with other aerosols (33.6%) is substantial. The ground-based spectral optical thickness and the refractive index estimated at visible and near-infrared wavelengths are used to account for the type of atmospheric aerosols. They are compared with four more AERONET sites located in India based upon their geographical distribution and extensive data availability. Simultaneously, single scattering albedo of dust is also inferred for all the available AERONET sites for the same period over India. The comparison results suggest that Jaipur arid background is more scattering in nature than Northern and Western regions in India. Finally, the absorption is less in summer than in winter over the Jaipur site.

 

 

Keywords: Aerosols; Optical thickness; Desert dust; Arid; Biomass; Angstrom exponent.

 

 

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