The Impact of the Ozone Hole on the Temperature and Salinity of the Southern Ocean

Abraham L Solomon, Columbia University of New York, Palisades, NY, United States, Lorenzo M Polvani, Columbia University, Department of Applied Physics and Applied Mathematics, New York, NY, United States, Ryan P Abernathey, Lamont -Doherty Earth Observatory of Columbia University, Palisades, NY, United States and Karen L Smith, University of Toronto, Physical and Environmental Sciences, Toronto, ON, Canada
Abstract:
Observations have revealed systematic changes in the temperature and salinity of the Southern Ocean since 1960. These trends reflect the evolving exchange of heat and momentum between atmosphere and ocean and are, in part, driven by anthropogenic emissions. The key question is: which emissions are most important, greenhouse gases or ozone depleting substances? We answer this question using CESM-WACCM, a comprehensive climate model with interactive stratospheric chemistry, coupled to state-of-the-art land, ocean and sea-ice components. In accord with recent observations, the model reproduces the recent warming and freshening of the upper 1000m of the Southern Ocean. Furthermore, employing an ensemble of single forcing integrations allows us to attribute a third of the changes in temperature and salinity to the presence of a seasonal ozone hole. While the warming is caused by a local change in the surface energy budget, the trend in salinity results from a combination of melting sea-ice and changing ocean transport.
Back to: Physical and Biogeochemical Processes in the Southern Ocean: Observations, State Estimation, and Modeling II