Investigation of Black Carbon characteristics over southern ocean: Contribution of fossil fuel and biomass burning

Black Carbon (BC) is an absorbing aerosol which has significant impact on the Earth - Atmosphere radiation balance and hence on climate. The variation of BC mass concentration and contribution of fossil fuel and biomass burning have been investigated over the Indian ocean sector of the Southern Ocean during austral summer. BC mass was in the range of 300-500 ng m(-3) between 23.3 degrees S to 24.5 degrees S followed by decrease in BC to 150 ng m(-3) as moving to higher southern latitudes till 41 degrees S latitude. An increase in BC mass from 250 to 450 ng m(-3) was found between 41 and 50 degrees S due to trap of air masses by cyclonic wind and transport of aerosols from the southern part of African and eastern Madagascar regions. Higher BC concentration (250-350 ng m(-3)) was observed in the latitude range of 57-60 degrees S which can be attributed to convergence of north-westerly and south-easterly winds. The dominant contributor to BC was fossil fuel, which was > 80% during half of the total observations, while > 20% biomass burning contributed to one fifth of observations. The coastal Antarctic region showed higher BC mass concentration with mixed type of contributions of biomass and fossil fuel. Such accumulation of BC near the Antarctic coast can have a crucial impact on the sea-ice albedo which significantly affect the Antarctic climate system locally and global climate in general. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the variation of black carbon (BC) mass concentration and its contributions from fossil fuel and biomass burning in the Indian Ocean sector of the Southern Ocean during the austral summer. The research found that fossil fuel was the dominant contributor to BC, accounting for over 80% in half of the observations, while biomass burning contributed to around one fifth.