Understanding the linkages between stratospheric variability and surface climate

Observations and experiments with numerical models reveal that stratospheric variability has a demonstrable effect on surface weather on a range of timescales. Stratospheric sudden warmings have been linked to changes in precipitation and the incidence of cold-air outbreaks throughout the Northern Hemisphere during winter. The Antarctic ozone hole has been linked to a range of observed climate trends over Antarctica and the Southern Ocean during summer. In this talk we examine the physical mechanisms that underlie the observed linkages between stratospheric variability and surface climate. The linkages are examined in the context of the fluxes of mass and potential vorticity in an isentropic coordinate system. The results provide novel insights into the physical mechanisms that drive the surface response not only to sudden stratospheric warmings, but to the Antarctic ozone hole as well.