My Climate Change News

The atmospheric aerosols play a key role in the regional/global climate system through scattering and absorption of incoming solar radiation and by modifying the cloud microphysics. Despite the large progress in quantifying the impact of different aerosols on radiative forcing, it still remains one of the major uncertainties in the climate change assessment. Precise measurements of aerosol properties are required to reduce the uncertainties, especially over the oceans and high altitude remote location in the Himalayas where they are scarce.

The study led by Dr Umesh Chandra Dumka (Scientist, ARIES, Nainital, India) along with contributions by Dr Shantikumar S. Ningombam (Scientist, IIA, Bangalore, India), Dr Dimitris G. Kaskaoutis (Scientist, National Observatory of Athens, Greece), Dr B. L. Madhavan (Scientist, National Atmospheric Research Laboratory, India) and other team members analysed the variability of aerosol optical, physical and radiative properties from January 2008 to December 2018 and the role of fine and coarse particles in aerosol radiative forcing (ARF) assessment. ARF is the effect of anthropogenic aerosols on the radiative fluxes at the top of the atmosphere and at the surface and on the absorption of radiation within the atmosphere.

The observations of the scientists show that the aerosol optical depth (AOD) exhibited a distinct seasonal variation with higher values (0.07) in May and lower (0.03) in winter months. The lower values of Ångström exponent (AE) in spring indicated the dominance of coarse-mode dust aerosols. An aerosol classification based on FMF and SSA revealed a dominance of medium-sized mixed aerosols over the Hanle and Merak, especially in Spring (53%). Pure and polluted dust exhibited fractions between 16% and 23%, with a low frequency of less than 13% of absorbing aerosols, denoting weak influence of anthropogenic aerosols and Black Carbon over the trans-Himalayan sites. Further, the aerosol...