Impact of BrO on dimethylsulfide in the remote marine boundary layer

Abstract

We have used a global three-dimensional chemical transport model coupled to a detailed size-resolved aerosol microphysics module to study the impact of BrO on dimethylsulfide (DMS) in the remote marine boundary layer. Our model results suggest BrO contributes 16% of the global annual DMS oxidation sink. This effect is most profound over the SH oceans where low NO xconcentrations and a high sea salt aerosol source, coupled with high DMS concentrations, drives a large contribution of BrO to DMS oxidation (>20%). Bromine chemistry also results in an 18% reduction in the global DMS burden and lifetime. In addition, when we use an alternative DMS source parameterization resulting in a factor 2 increase in DMS flux the release of bromine from sea salt aerosol increases by 50-60% in the southern hemisphere summer because of additional aerosol acidity. This suggests a possible DMS-SO2-sea salt-BrO marine aerosol feedback mechanism that acts to reduce the sensitivity of the DMS lifetime to increases in DMS emission. © Copyright 2010 by the American Geophysical Union.