polar vortex

Polar Vortex and Sudden Stratospheric Warmings

The Polar Vortex is a phenomenon seen in the stratosphere, in the winter hemisphere only. It occurs at a height of around five to thirty miles and forms because air above the winter pole cools markedly in response to the lack of solar radiation experienced there at that time of year. This cooling makes the air more dense, leading to a high pressure area near the surface but a low pressure area aloft, as illustrated by Image 1.