Dependence of stratosphere–troposphere coupling on tropospheric jet latitude and seasonality

A dry primitive equation model is used to explain how coupling between the stratospheric polar vortex and the tropospheric extratropical circulation depends on tropospheric jet latitude and seasonality. The tropospheric response to an identical stratospheric jet configuration is strongest for a jet that resembles that in the Southern hemisphere and weakest for a jet that resembles that in the North Pacific. If the extratropical circulation is zonally asymmetric, the response to the vortex is greatest in the exit region of the tropospheric jet, consistent with modelled changes in Rossby wave breaking. The effects of seasonality will be explored as well. Implications for the tropospheric response to stratospheric ozone anomalies are discussed.