Numerical simulation of the dynamical response of the Arctic Vortex to Aerosol‐associated chemical perturbations in the lower stratosphere

A general circulation model has been coupled interactively to a stratospheric photochemistry model to study the dynamical response of the Arctic polar vortex to ozone depletion catalyzed by volcanic aerosols. It is found that temperatures may be depressed by as much as 3–7 K in late March in the lower stratosphere at northern mid‐ and high‐latitudes owing to ozone‐radiation‐dynamics feedback effects. A corresponding delay in the breakdown of the stratospheric vortex (that is, the final warming) is predicted. Further, a dipole‐like anomaly in the zonal‐mean zonal wind, extending downward from the stratosphere into the troposphere, is found. In the model, the reduced solar heating in late winter and early spring associated with aerosol ozone depletion acts as a trigger for the net cooling that is observed. However, a major part of the cooling is related to anomalies induced in the circulation of the lower stratosphere. Our simulations demonstrate the close coupling between the dynamics and chemistry of the lower stratosphere, and the complexity in analyzing cause and effect related to perturbations in this region.