Seminar:

Abstract: The westerly winds in the Southern Hemisphere modulate climate. They have been strengthening and shifting southward impacting global ocean circulation, Antarctic ice, CO₂ air-sea flux, etc.  Loss of Antarctic ozone, along with global warming, have contributed to an increase in temperature difference (DT) between the mid and high latitudes, likely explaining much of the changes in the westerlies.  However, we estimate a substantial increase in dimethyl sulphide (DMS) sea-to-air flux from the Southern Ocean (SO), as a result of these changes. Over the last 20 and 50 years the peak summertime DMS flux has increased 25 and 45 percent.  DMS is produced by phytoplankton and is emitted to the atmosphere, where it can be oxidized, produce new particles or add to existing ones and enhance cloud reflectivity.  Increasing DMS fluxes may be contributing to the greater cloud albedo in the SO region and increasing DT. Thus, further strengthening the westerlies and shifting them pole ward resulting in a positive feedback.