Aerosol and cloud radiative properties over India and adjoining Seas

Abstract

newline Aerosols are ubiquitous in the atmosphere and significantly impact air quality, human health, newlineweather and climate. Due to rapid industrialisation and urbanisation, India is a global hotspot newlineof aerosols, particularly Indo-Gangetic Plain (IGP). Multivariate and multidimensional newlineinformation from various sensors (ground and space) and models have extensively been newlineintegrated over the last two decades to characterise aerosols. But the uncertainties in the aerosol newlineclimatic effects remain significant owing to nonuniform spatial and temporal sampling and newlinecoverage and considerable heterogeneity in aerosol sources. Here, we analyse the aerosol and newlinecloud variables from space-borne sensors and model reanalysis products to delineate how to newlineinvestigate atmospheric aerosol properties and impact on regional climate under the reduced newlineanthropogenic emissions radiative effects of aerosol and clouds over Indian continental newlineadjoining marine areas. Numerous investigators reported the increasing trend in anthropogenic newlineaerosols over India, particularly over IGP. In recent years, the rising trend in aerosols has been newlinehigher over Central India (CI) than IGP. The enhanced lower tropospheric stability over CI due newlineto aerosol-induced positive forcing on the atmosphere and negative forcing at the surface newlinecreated a positive feedback mechanism that could further favour the accumulation of aerosols newlinenear the surface. The continental aerosol outflow onto the Bay of Bengal (BoB) during the premonsoon newline(March through May) is a year-round phenomenon, which constitutes a mixture of newlinemineral dust and anthropogenic aerosols. A drastic reduction in anthropogenic emissions due newlineto the pandemic outbreak of novel coronavirus (COVID-19) imposed lockdown in 2020 newlineprovided a unique and rare opportunity to estimate the anthropogenic contribution to aerosol newlineforcing over the outflow region of the BoB. A 10 25% reduction in aerosol loading over the newlineIGP resulted in a 20-25% reduction in aerosol direct radiative forcing over the outflow region newlineof the BoB. Us