10th International Aerosol Conference
September 2 - September 7, 2018
America's Center Convention Complex
St. Louis, Missouri, USA

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Estimates of Radiative Forcing by Carbonaceous Aerosols over Northern India

A.S. Panicker, R. Aditi, G. BEIG, K. Ali, IITM, Pune, India

     Abstract Number: 15
     Working Group: Carbonaceous Aerosol

Abstract
Sampling of PM2.5 particles over two Northern Indian Cities (Jabalpur (JBL) and Udaipur (UDPR)) were carried out during November 2011-November 2012 (up to September 2012 over UDPR). An advanced DRI Thermal optical carbon Analyzer was used to extract the Elemental Carbon (EC) and Organic Carbon (OC) using Impove_A protocol from the sampled filter papers. The elemental carbon concentrations were up to 7.36 ± 1.99 µgm-3 over JBL and were as high as 10.78 ± 4.85 µgm-3 over UDPR. Whereas the corresponding OC concentrations showed much larger concentration in different seasons (as high as 19.37±12.6 µgm-3 over JBL and was up to 39.71±13.05 µgm-3over UDPR). The radiative forcing for OC and EC has been estimated using Optical properties of Aerosols and Clouds (OPAC) model along with a radiative transfer model (Santa Barbara Discrete Ordinate Radiative transfer Model). The surface forcing for OC found to be -1.99 ± 0.99 Wm-2 to -2.76± 1.96 Wm-2 over JBL and -1.36± 1.06 Wm-2 to -4.67 ± 1.76 Wm-2 over UDPR. The Top of the Atmosphere (TOA) forcing values found to be -0.53 ±0.39Wm-2 to -1.50± 0.70Wm-2 over JBL and -0.75 ± 0.59 Wm-2 to -2.07 ± 1.35 Wm-2 over UDPR. However the magnitude of EC forcing found to be more than ten fold higher than OC forcing (As high as -20.10 Wm-2 at surface and +9.1Wm-2 at TOA over JBL and -34.35 Wm-2 at surface and + 12.51 Wm-2 at TOA over UDPR) due to its strong atmospheric absorption, inspite of much lower concentration compared to OC.

Key words: Organic Carbon, Elemental Carbon, radiative forcing