Tropospheric response to stratospheric perturbations in a relatively simple general circulation model

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Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: Impact of the Seasonal Cycle

The seasonal time dependence of the tropospheric circulation response to polar stratospheric cooling in a simple atmospheric general circulation model is investigated. When the model is run without a seasonal cycle, polar stratospheric cooling induces a positive annular-mode response in the troposphere that takes a remarkably long time—several hundred days—to fully equilibrate. One is thus led ...

Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Role of Eddies

The extratropical circulation response to cooling of the polar-winter stratosphere in a simple AGCM is investigated. The AGCM is a dry hydrostatic primitive equation model with zonally symmetric boundary conditions and analytically specified physics. It is found that, as the polar-winter stratosphere is cooled, the tropospheric jet shifts poleward. This response projects almost entirely and pos...

Stratosphere–Troposphere Coupling in a Relatively Simple AGCM: The Importance of Stratospheric Variability

The impact of stratospheric variability on the dynamical coupling between the stratosphere and the troposphere is explored in a relatively simple atmospheric general circulation model. Variability of the model’s stratospheric polar vortex, or polar night jet, is induced by topographically forced stationary waves. A robust relationship is found between the strength of the stratospheric polar vor...

Stratospheric influence on the tropospheric circulation revealed by idealized ensemble forecasts

[1] The coupling between the stratosphere and troposphere following Stratospheric Sudden Warming (SSW) events is investigated in an idealized atmospheric General Circulation Model, with focus on the influence of stratosphericmemory on the troposphere. Ensemble forecasts are performed to confirm the role of the stratosphere in the observed equatorward shift of the tropospheric midlatitude jet fo...