Dimethylsulfide sea-to-air fluxes in Chukchi Sea and East Siberian Sea in the summer of 2016 and 2017

Abstract

In the global radiation budget estimate, the largest uncertainty is derived by the current understanding of sulfate aerosols. Dimethylsulfide (DMS) is the major biogenic source of sulfate aerosols in the remote marine atmosphere. DMS production in the oceans is closely associated with phytoplankton biomass because it is produced by the phytoplankton activity. Arctic is warming faster than any other region on Earth due to the global warming. The decline in sea ice and the rise in sea surface temperature also affect the production of DMS by changing marine ecosystems. In this study, we measured continuous underway surface DMS and ΔO2/Ar during R/V Araon’s 2016 and 2017 summer Arctic expeditions. The high-resolution DMS concentrations are obtained in Chukchi Sea and East Siberian Sea, using membrane inlet mass spectrometry (MIMS). Surface DMS concentrations varied between ~1 to 31 nM (mean 6 ± 7 nM) in 2016 and between ~1 to 105 nM (mean 7 ± 14 nM) in 2017. Sea-to-air flux estimates of DMS were determined using the empirical dependence of exchange coefficients on wind speed, surface water DMS concentrations. Surface atmospheric DMS concentrations are assumed to zero. Surface water DMS measurements yielded sea-to-air flux estimates of DMS ranged from 0.01 to 82.50 μmol m2d1 (mean 10.96 ± 15.50 μmol m2d1) in 2016 and from 0.00 to 404.43 μmol m2d1 (mean 9.82 ± 27.95 μmol m2d1) in 2017. This study contributes to broadening the spatial coverage of the Arctic DMS dataset and serves as a baseline for future studies.