The Effects of Interactive Stratospheric Chemistry on Climate Simulations in a Coupled Atmosphere-Ocean General Circulation Model
Consistent with previous studies using prescribed sea surface temperatures and sea ice concentrations, the interactive chemistry runs simulate a deeper Antarctic ozone hole and consistently larger changes in surface pressure and winds at the Southern Hemisphere high latitudes than the prescribed ozone runs. It is also found that interactive chemistry changes stratospheric circulations, which leads to a weaker Brewer-Dobson circulation and higher temperature in the upper troposphere and lower stratosphere compared to the prescribed ozone case. The use of a coupled atmosphere-ocean model in this study enables us to determine the impacts of interactive chemistry on simulations of ocean circulation and sea ice. Interactive chemistry produces statistically significant lower sea surface temperature in the north Pacific and north Atlantic. In the Southern Ocean, the interactive chemistry runs have larger circulation trends with stronger changes in northerly and westerly surface flow near the Antarctica continent and stronger upwelling near 60oS. Using interactive chemistry also simulates a larger decrease of Antarctic sea ice concentrations. We will discuss what causes these differences. Our results highlight the importance of using interactive chemistry in order to correctly capture the influences of stratospheric ozone forcing on climate simulations.