AGU: Geophysical Research Letters

 

Editors' Highlight

Sensitivity of Southern Hemisphere climate to variable ozone concentrations

Seasonal variation in stratospheric ozone concentration over Antarctica is large, with the greatest depletions occurring in the austral spring when the Sun returns to Antarctica. The resulting ozone hole, which is often displaced from the pole, cools the stratosphere because less ozone means less absorption of ultraviolet radiation. Although models suggest that the ozone hole also cools the troposphere over Antarctica, simulations are not entirely realistic because ozone concentrations used in models are usually averaged over latitude bands. Noting that ozone concentrations are more heterogeneous than this, Crook et al. (2008) prescribed a realistic three-dimensional distribution of ozone in a high-vertical-resolution atmospheric model and simulated the climate response to this ozone distribution. Comparing results with simulations containing averaged ozone concentrations revealed that the three-dimensional ozone yields cooler temperatures in the stratosphere and upper troposphere, with a magnitude of cooling comparable to that caused by ozone depletion itself. This result suggests that heterogeneous ozone concentrations influence Southern Hemisphere climate and that this influence will change in the future as the recovery of ozone decreases this heterogeneity.

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