9.1 Connection between Antarctic ozone depletion and tropospheric Rossby wave breaking and cut-off lows

Thursday, 27 January 2011: 8:45 AM
3B (Washington State Convention Center)
Thando Ndarana, Johns Hopkins Univ., Baltimore, Maryland; and D. Waugh, L. Polvani, G. J. P. Correa, and E. P. Gerber

The connection between the formation of the Antarctic ozone hole and upper tropospheric Rossby Wave Breaking (RWB) and Cut-off Lows (COLs) is examined using meteorological reanalyses and simulations using both realistic and idealized atmospheric general circulation models. The reanalyses show an increase in the occurrence of RWB and COLs in middle latitudes during southern summer over the last thirty years. Consistent changes in RWB and COLs are found in time-slice simulations whose stratospheric ozone distributions differ between 1960 and 2000, but not in simulations that differ only in their greenhouse gas concentrations and sea surface temperatures. This support the hypothesis that the observed increases in RWB and COL are due to the formation of the stratospheric ozone hole. Changes in RWB are also found in idealized model simulations which differ only in the strength of the polar vortex, and provide insights into the mechanisms involved in the ozone hole – tropospheric RWB connection.
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