Aerosol characteristics during the coolest june month over new delhi, northern india

• Main Authors: Kumar, A, Tiwari, S, Bisht, DS, Devara, PCS, Goloub, P, Li, Z, Srivastava, MK
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Taylor and Francis 2011
• Subjects: Meteorology and Climatology; Aerosol Robotic Network
• Online Access: http://moeseprints.incois.gov.in/692/; http://www.scopus.com/inward/record.url?eid=2-s2.0-82055162753&partnerID=40&md5=2b38cea07f374e2e8b0f77fa51151e41

June 2008, which is also the transition month between two major seasons for Indo-Gangetic Basin (IGB), has been identified the coolest June over New Delhi during the past century, showing mean temperature of 31.6 ± 1.7°C, which was found to be ~2°C less than its climatological mean (33.9°C). Aerosol optical properties for this month and thus obtained physical parameters have been studied using data from the CIMEL sun/sky radiometer, installed in New Delhi under the Aerosol Robotic Network (AERONET) programme. Results reveal bimodal aerosol volume size distribution. The monthly mean values for aerosol optical depth (AOD) at 500 nm (0.96 ± 0.31) and à ngström exponent at the wavelength pair of 440-870 nm (0.79 ± 0.42) show significant lower values whereas single scattering albedo at 675 nm shows a significantly larger value (0.94 ± 0.04) compared with previous measurements over the station. Results suggest dominance of scattering- type particles such as water-soluble aerosols from anthropogenic sources and dust aerosols from natural sources with higher relative humidity over the station. Radiative forcing caused due to the aerosols for the month of June 2008, which have been computed using the radiative-transfer model, informs low forcing at the top of atmosphere (TOA, +14 W -m) as well as at surface (-33 W m-2). The resultant atmospheric forcing (+47 W m-2) indicates warming effect that caused heating of lower atmosphere at the rate of 0.89 K day-1.