Cooling of the Antarctic ozone hole is controlled by dynamics as well as by radiation

A model simulation, forced by prescribed ozone depletion, suggests strong dynamical controls on the large springtime cooling of the polar stratosphere associated with the Antarctic ozone hole. We use a transformed Eulerian mean analysis to examine the dynamics. We find that in late spring the expected radiative cooling in response to ozone depletion is almost cancelled above 100 hPa by an increase in dynamical heating. But between 300 and 100 hPa the radiative cooling is enhanced by the dynamics, resulting in a cold anomaly down to the tropopause. In early summer, increased dynamical heating dominates as the radiative cooling diminishes, resulting in a net warming and the delayed break-up of the lower stratospheric vortex. The anomalous dynamical heating is driven by changes in the Brewer-Dobson circulation arising primarily from the dissipation of resolved planetary waves.