This is a phenomenon that occurs during the polar winter in which stratospheric air moves in a circular motion, with an area of relatively still air in its center. The temperature in the vortex is approximately -130 degrees F (-80 degrees C), which assists in the formation of polar stratospheric clouds. Though usually more prolonged and colder over Antarctica, the Arctic polar vortex does form to a degree, and when the temperatures there are coldest and the vortex persists, Arctic stratospheric ozone destruction on Arctic polar stratospheric clouds has also been observed.
[Science; v251; 46-52; 1991.] [Journal of the Atmospheric Sciences; v51; 2973-2994; 1994.] [Elements: Air; Michael Allaby; page 160; 1992; Facts on File Inc; New York.] [Antarctica; Carl Eklund and Joan Beckman; page 83; 1963; Holt, Rinehart and Winston, Inc; New York.]
Source: Atmospheric Chemistry Glossary