Berlin 2005 – scientific programme
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UP: Umweltphysik
UP 9: Poster: Atmosph
äre und Klima
UP 9.1: Poster
Tuesday, March 8, 2005, 10:15–12:15, Poster TU HTF
Interactions of sulfur and halogens in the marine boundary layer — •Roland von Glasow1,2 and Paul J. Crutzen2,3 — 1Institut für Umweltphysik, Universität Heidelberg, Heidelberg, Germany — 2Scripps Inst. of Oceanography, UCSD, La Jolla, USA — 3Max-Planck Institut für Chemie, Mainz, Germany
The oxidation of DMS is the main source of SO2, MSA, and non-sea-salt sulfate in the clean marine boundary layer (MBL). Recently the importance of BrO - in addition to OH and NO3 - has been suggested as oxidant for DMS. Furthermore HOCl(aq) and HOBr(aq) can increase the oxidation of S(IV) to S(VI) in aerosol and cloud particles. Chlorine and bromine in the MBL are derived from seasalt aerosol. We investigated the importance of these processes for the chemistry of the MBL and possible climate links with the one-dimensional chemical and microphysical model MISTRA-MPIC. BrO plays a very significant role as oxidant even under very low mixing ratios of 0.5 pmol/mol. We found that still significant uncertainty exists in the kinetics of DMS oxidation especially with regard to the endproducts of DMS oxidation. Under most conditions that we studied the net effect of halogens, especially under cloudy conditions, is an increase in particulate sulfur (MSA plus nss-sulfate) and decrease of precursors for the formation of new CCN.