Seasonal variability in aeolian dust deposition fluxes and their mineralogical composition over the Northeastern Arabian Sea

Abstract

Atmospheric mineral dust is derived from arid/semi-arid region, undergoes long-range transport, and can impact surface biogeochemical processes in the pristine marine region.This study reports fluxes of mineral dust (wet and dry deposition), their clay mineralogy, and associated seasonal variability over the Northeastern Arabian Sea.Dust sources are assessed using mineral composition and their ratios as well as satellite retrievals during 2012-2015.The average wet deposition flux (293 mg m-2 day-1) of mineral dust is three times higher than dry deposition flux (96 mg m-2 day-1).A clear distinction is observed in the mineral composition of wet and dry deposited dust with smectite and palygorskite being dominant during the wet period and illite and chlorite being dominant during the dry period.Mineralogical composition and their ratios indicate that major dust sources to the Northeastern Arabian Sea are from northeast Africa, Arabian Peninsula, and southwest Asia.These observations are corroborated with the satellite retrievals, aerosol optical depth, and back trajectory analyses.