A Minimal, Adiabatic Example of Sudden Stratospheric Warming

Sudden Stratospheric Warming (SSW) are extreme weather events that can significantly impact weather patterns on short to subseasonal to seasonal timescales. In this study, we present a new idealized test case of a Sudden Stratospheric Warming (SSW) event implemented in GFDL's FV3 dynamical core. The initial condition features a wintertime stratospheric circulation with a westerly jet in the Northern Hemisphere and an easterly jet in the Southern Hemisphere. In the absence of tropospheric wave forcing, the model preserves the stratospheric circulation for approximately 200 days. To induce SSW, we introduce a moving mountain to generate planetary waves. Wavenumber-1 forcing led to a vortex displacement SSW, while wavenumber-2 forcing produced a vortex split SSW, consistent with observational data and literature. This minimal setup offers a controlled environment for studying SSW dynamics and serves as a useful testbed for evaluating the ability of dynamical cores to capture key stratospheric processes and troposphere-stratosphere interactions.