GFDL - Geophysical Fluid Dynamics Laboratory

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Sensitivity of polar ozone to sea surface temperatures and halogen amounts.

Key Findings

  • The simulations show that the ozone hole is sensitive to SSTs via their effect on the Brewer-Dobson circulaton.
  • The sensitivity of the model results to the specification of bromine indicates the need to include realistic bromine amounts as well as chlorine and may explain, in part, the substantial underpredictions of the ozone hole area in previous simulations.
  • The results also suggest that a small residual ozone hole may still be present after 2070 and that the ozone hole may not disappear entirely this century.

The results of the simulations of Austin and Wilson (2010) suggest the importance of including a coupled ocean on stratospheric processes as well as realistic bromine amounts, including the very short lived species. The figure shows the calculated area of the ozone hole (colored lines and triangles), together with observations (black triangles). With SSTs from the CM2 coupled ocean-atmosphere experiment, the simulated ozone hole (blue) tends to be slightly larger (by about 6%) than simulated with observed SSTs used as forcing (red curve and points). For the low Bromine simulation (green), which corresponds approximately to just the long lived bromine species, the ozone hole was smaller by about 10%. Recent model developments have eliminated the small but significant bias between observations and model results shown in the figure below.


Reference:

Austin, John, and R John Wilson, 2010, Sensitivity of polar ozone to sea surface temperatures and halogen amounts. Journal of Geophysical Research, 115, D18303, doi:10.1029/2009JD013292.