The Impact of Increasing Westerly Winds on Dimethyl Sulfide Flux over the Southern Ocean: a Possible Positive Climate Feedback

Wind and sea surface temperature data from the National Centers for Environmental Prediction (NCEP) were employed along with a sea-air gas transfer velocity and the latest DMS climatological data to examine temporal changes in the dimethyl sulphide (DMS) flux over the Southern Ocean, comparing the periods 1980-1989 to 2000-2009 and 1950-1959 to 2000-2009. Our analysis shows an increase in DMS flux, as a result of poleward shifting and strengthening of the Westerly winds. DMS is produced by phytoplankton and is emitted to the atmosphere, where it can be oxidized, produce new particles or add to existing particles, and enhance cloud reflectivity (albedo). Therefore, increasing DMS fluxes may be contributing to the reported increase in cloud albedo in the Southern Ocean region and around Antarctica. Brighter clouds in this region may in turn provide a positive feedback, intensifying and further shifting the Southern Westerly winds poleward, potentially modifying the Earth's albedo and energy budget.