Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305;
Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305.
Proc Natl Acad Sci U S A. 2020 Mar 3;117(9):4505-4510. doi: 10.1073/pnas.1919344117. Epub 2020 Feb 18.
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, HOOCHSCHO), 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.
二甲基硫（DMS）从海洋中排放，是海洋大气中硫的最丰富的生物来源。大气中的 DMS 被氧化为可凝结的产物，形成二次气溶胶，通过散射太阳辐射和充当云凝结核来影响地球的辐射平衡。我们报告了大气中二甲基硫氧化产物羟甲基硫代甲酸盐（HPMTF，HOOC-SCHO）的先前未量化的发现，通过全球范围内的空气传播观测证明了它是海洋硫的主要储存库。受观测约束的模型结果表明，超过 30%排放到大气中的海洋 DMS 形成 HPMTF。同时的粒子测量表明 HPMTF 浓度与新粒子形成和生长之间存在紧密联系。对这些观测的分析表明，必须在大气模型中包含 HPMTF 化学，以改善海洋生物地球化学、海洋气溶胶形成和生长及其对气候的综合影响之间的关键联系的代表性。
