A rotating polar high pressure system, formed as a distinct column of cold air in the middle to lower stratosphere, developed during the long polar night; wind speeds may reach 100 metres s−1. Upper troposphere air is sucked into the vortex, then sinks to cause polar highs. See Chshyolkova et al. (2007) Angeo 25 on the Arctic Polar vortex.
Subjects: Meteorology and Climatology.