Response of an interactive two‐dimensional model to ozone changes: An estimate of the radiative dynamical feedback effect

Abstract

The response of an interactive two‐dimensional model of the stratosphere to increased chemical removal of ozone is studied. A simplified ozone chemistry model was used. The radiative dynamical feedback in the model leads to a recovery of about one third of the calculated ozone decrease at high altitudes, and to about one sixth of the predicted losses in the column densities at high latitudes when compared with predictions by a model with fixed temperature and circulation. The model response is analyzed with the aid of stationary linear models for the diabatic circulation. A simple interpretation of the adjustment of dynamical quantities is obtained by comparing the global mean and the differential solar heating rates derived from perturbed and unperturbed ozone distributions. The feedback effect can be qualitatively described as (1) an adjustment of the global mean temperature in response to global mean solar heating changes and (2) an approximately linear response in all other dynamical variables, proportional to the change in the differential heating. The exact magnitude of the feedback effect on ozone in our model is a function of the simplified treatment of the photochemistry; however, we believe that the structure of the ozone changes and the interpretation of the dynamical response is independent of the details of the chemistry. Our model results further show an increase in the predicted high‐latitude ozone depletion with decreasing eddy diffusion in the model stratosphere. This effect can be explained by the reduction of advective and diffusive horizontal transport from the tropics to the polar region in the lower stratosphere with decreasing eddy diffusion.