Atmospheric & Environmental Chemistry Seminar

Timothy Bertram, Professor, University of Wisconsin-Madison, will discuss "Rethinking Dimethyl Sulfide Oxidation and Aerosol Sulfate Formation in the Marine Boundary Layer." Harvard community only.

Timothy Bertram, Professor, University of Wisconsin-Madison, will discuss "Rethinking Dimethyl Sulfide Oxidation and Aerosol Sulfate Formation in the Marine Boundary Layer."

Abstract: Ocean emissions of dimethyl sulfide (DMS) are a major precursor for the production and growth of aerosol particles, which can act as seeds for the formation of cloud droplets in the marine atmosphere with the subsequent impacts on Earth’s climate. Global aircraft observations indicate that DMS is efficiently oxidized to hydroperoxymethyl thioformate (HPMTF), a previously unrecognized molecule, which necessitates revisiting DMS oxidation chemistry in the marine atmosphere. In this seminar, I will show through ambient observations, laboratory studies, and global modelling that a dominant loss pathway for HPMTF is uptake into cloud droplets. This loss process short circuits gas-phase oxidation and significantly alters the dynamics of aerosol production and growth in the marine atmosphere and the production of long-lived precursors for stratospheric sulfate production.

Contact: zhenqu@g.harvard.edu

Registration required. Harvard community only.