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The Antarctic Atmospheric Energy Budget. Part II: The Effect of Ozone Depletion and its Projected Recovery

Smith, Karen L.; Previdi, Michael; Polvani, Lorenzo M.

In this study we continue our investigation of the atmospheric energy budget of the Antarctic polar cap (the region poleward of 70°S) using integrations of the Whole Atmosphere Community Climate Model from the year 1960 to 2065. In agreement with observational data, we find that the climatological mean net top-of-atmosphere (TOA) radiative flux is primarily balanced by the horizontal energy flux convergence over the polar cap. On interannual timescales, changes in the net TOA radiative flux are also primarily balanced by changes in the energy flux convergence, with the variability in both terms significantly correlated with the Southern Annular Mode (SAM); positive and negative correlations, respectively. On multidecadal timescales, twentieth century stratospheric ozone depletion produces a negative trend in the net TOA radiative flux due to a decrease in the absorbed solar radiation within the atmosphere-surface column. The negative trend in the net TOA radiative flux is balanced by a positive trend in energy flux convergence, primarily in austral summer. This negative (positive) trend in the net TOA radiation (energy flux convergence) occurs despite a positive trend in the SAM, suggesting that the effects of the SAM on the energy budget are overwhelmed by the direct radiative effects of ozone depletion. In the twenty-first century, ozone recovery is expected to reverse the negative trend in the net TOA radiative flux, which would then, again, be balanced by a decrease in the energy flux convergence. Therefore, over the next several decades, ozone recovery will, in all likelihood, mask the effect of GHG warming on the Antarctic energy budget.

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Title
Journal of Climate
DOI
https://doi.org/10.1175/JCLI-D-13-00173.1

More About This Work

Academic Units
Applied Physics and Applied Mathematics
Lamont-Doherty Earth Observatory
Ocean and Climate Physics
Earth and Environmental Sciences
Publisher
American Meteorological Society
Published Here
November 19, 2013
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