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

Thursday, 18 December 2014: 5:15 PM
Abraham l Solomon1, Lorenzo M Polvani2, Ryan P Abernathey1 and Karen L Smith3, (1)Columbia University of New York, Palisades, NY, United States, (2)Columbia University, New York, NY, United States, (3)Lamont -Doherty Earth Observatory, Palisades, NY, United States
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. We find that the
changes in Southern Ocean temperature South of 60S are primarily due to
the presence of a seasonal ozone hole, and between 60S and 40S the
trends are driven in equal measure by ozone depletion and all other
forcings combined. Furthermore, we demonstrate substantial changes in
the model's ocean salinity, and show that these are greatly enhanced by
formation of the ozone hole, a fact that has not been previously reported.