Assessment of two intense dust storm characteristics over Indo - Gangetic basin and their radiative impacts: A case study

摘要

The present study is focused to examine the impacts of two intense dust storms on aerosol characteristics and their radiative impacts occurred in pre-monsoon season of 2018 (i.e. 17 May and 14 June 2018) over Kanpur (26.51 degrees N, 80.23 degrees E, 123 above nisi). Moderate Resolution Imaging Spectroradiometer (MODIS) true colour images, trajectory pathways of dust storm along with satellite observation and AErosol RObotic NETwork (AERONET) measurements confirms that both the dust storms are either originated from or transported over the Thar Desert, causing a higher aerosol loading which spread over entire Indian-Gangetic Basin (IGB) and modifying the aerosol optical (i.e. aerosol optical depth, angstrom exponent, refractive index etc.), physical (i.e. size distribution) and radiative properties (i.e. single scattering albedo, asymmetric parameter). The space-borne Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) - retrieved aerosol measurements reveal the presence of elevated dust/polluted dust aerosol (up to 3-5 km) over IGB which is well corroborated with aerosol characteristics observed by MODIS, Ozone Monitoring Instrument (OMI) and Atmospheric Infrared Sounder (AIRS). The Dust Regional Atmospheric Model (DREAM8b) shows a good agreement with satellite retrievals with higher value of surface dust concentration in the range of 320-640 mu g/m(3) over Kanpur during the dust storm days. An enhancement in monthly mean outgoing longwave radiation (up to 60 Wm(-2)) is observed over IGB and downwind flow region during the dust storm days. The atmospheric aerosol radiative forcing is found 124 Wm(-2) and 84 Wm(-2) during both the dust storm days (17 May and 14 June 2018) associated with heating rate 2.69 K day(-1) and 1.84 K day(-1) respectively which may be significant to affect the regional atmospheric dynamics and hence the climate system also.