Stronger Stratospheric Temperature Changes Simulated with an Interactive Ozone Scheme

Changes in the stratospheric ozone play important roles in shaping the climate over the historical period. While the direct radiative effects of ozone changes is straightforward to understand and is well simulated in most climate models, the full interaction between ozone and climate involves much more processes and lacks a complete understanding. Here, we compare GFDL AM4 simulations with prescribed ozone versus interactive ozone. The interactive ozone is simulated either with full chemistry scheme or a simple linear scheme. Despite the similar amount of ozone depletion in the lower stratosphere, the model with interactive ozone simulates significant stronger stratospheric cooling over the Antarctica. This is because the coherence between the ozone eddies and temperature eddies leads to a weaker radiative damping to the waves in the stratosphere from ozone’s shortwave radiative effects, which results in a weaker dynamical heating over the polar region. Prescribing monthly ozone eliminates this coupling between ozone and dynamics and yields stronger dynamical cooling to compensate the radiative cooling. We also show that the simple linear ozone scheme simulates temperature and ozone responses similar to the full chemistry scheme with a much cheaper computational cost.