Meteorology of the polar vortex: Spring 1997

The 1996-1997 northern hemisphere spring polar vortex was very strong, cold, and symmetric, somewhat similar to those found in the Antarctic spring vortex. The vortex did not form until late in December and was very symmetric from February into late April. The spring vortex was characterized by record low temperatures, record low ozone amounts as measured from the Total Ozone Mapping Spectrometer (TOMS) instruments, and a wide band of strong winds in the lower stratosphere. Spring wave activity was greatly reduced, with 100 hPa February-March eddy heat fluxes that were lower by a factor of 2 from any previously observed values over the last 18 years.