The antarctic ozone hole and the northern annular mode: a stratospheric interhemispheric connection

Abstract

The S.H. ozone hole deepened into the mid-1990s, while the Northern Annular Mode (NAM) became more positive. Both effects have since stabilized. We investigate a possible connection with modeling experiments of a S. H. spring ozone hole, and also year-round ozone loss in both polar regions. The S.H. ozone hole results in a more positive NAM-like phase extending down to the surface. Reduced vertical stability increases S.H. tropospheric wave energy flux into the stratosphere which drives a residual circulation with relative subsidence over the Southern pole and upwelling and reduced planetary wave energy flux at Northern high latitudes. The results suggest that similar trends in the Southern Ozone hole and the NAM over the last 20 years may be more than just a coincidence, although other factors undoubtedly influence the Northern high latitude circulation. Copyright 2009 by the American Geophysical Union.