Global airborne sampling reveals a previously unobserved dimethyl sulfide oxidation mechanism in the marine atmosphere.
Patrick R VeresJ Andrew NeumanTimothy H BertramEmmanuel AssafGlenn M WolfeChristina J WilliamsonBernadett WeinzierlSimone TilmesChelsea R ThompsonAlexander B ThamesJason C SchroderAlfonso Saiz-LopezAndrew W RollinsJames M RobertsDerek PriceJeff PeischlBenjamin A NaultKristian H MøllerDavid O MillerSimone MeinardiQinyi LiJean-François LamarqueAgnieszka KupcHenrik G KjaergaardDouglas E KinnisonJose L JimenezChristopher M JerniganRebecca S HornbrookAlan HillsMaximilian DollnerDouglas A DayCarlos A CuevasPedro Campuzano JostJames BurkholderT Paul BuiWilliam H BruneSteven S BrownCharles A BrockIlann BourgeoisDonald R BlakeEric C ApelThomas B RyersonPublished in: Proceedings of the National Academy of Sciences of the United States of America (2020)
Dimethyl sulfide (DMS), emitted from the oceans, is the most abundant biological source of sulfur to the marine atmosphere. Atmospheric DMS is oxidized to condensable products that form secondary aerosols that affect Earth's radiative balance by scattering solar radiation and serving as cloud condensation nuclei. We report the atmospheric discovery of a previously unquantified DMS oxidation product, hydroperoxymethyl thioformate (HPMTF, HOOCH2SCHO), identified through global-scale airborne observations that demonstrate it to be a major reservoir of marine sulfur. Observationally constrained model results show that more than 30% of oceanic DMS emitted to the atmosphere forms HPMTF. Coincident particle measurements suggest a strong link between HPMTF concentration and new particle formation and growth. Analyses of these observations show that HPMTF chemistry must be included in atmospheric models to improve representation of key linkages between the biogeochemistry of the ocean, marine aerosol formation and growth, and their combined effects on climate.