My PhD looks at the dynamics of the polar vortex. This is a large scale cyclone which develops in the Earth's stratosphere at the winter pole. The polar vortex may break down during the winter causing a warming of the stratosphere by several tens of degrees in an event known as a stratospheric sudden warming.
These warming events can have impacts on tropospheric weather, affecting the intensity and locations of storms, cold spells over Northern Europe having an increased probability and an increase in tropospheric blocking at high latitudes.
My PhD looks at the dynamics of these events, in particular the removal of air from the vortex in the period prior to the sudden warming.