The Mesospheric Polar Vortex during Sudden Stratospheric Warmings

It is well known that the stratospheric polar vortex weakens, splits in two, or is temporarily obliterated during sudden stratospheric warming (SSW) events. It is also well known that there is cooling in the mesosphere during these large planetary wave-driven disturbances. However, it is less understood how this cooling impacts the size and shape of the polar vortex at mesospheric altitudes. Does the vortex in the mesosphere strengthen in response to this cooling or does it weaken as it does in the stratosphere? Here we will leverage novel methodologies to identify the polar vortex edge at both stratospheric and mesospheric altitudes on each day. We will then explore how the position, shape, and size of the mesospheric polar vortex evolves on a day-to-day basis during minor, major, vortex displacement, and vortex split SSW events during the 2004-2018 period. Unexpected variability in the mesosphere will be highlighted, including recent results that indicate a contraction of the mesospheric vortex following prolonged SSWs.