THE COLD STRATOSPHERIC WINTERS 1994 1995 AND 1995/1996/

The stratospheric winters 1994/1995 and 1995/1996 were both extremely cold. The temperature (T) fell below that necessary for type 1 polar s tratospheric cloud formation (195 K at 50 hPa) on many consecutive day s in each winter and occasionally reached values low enough for ice cl oud formation. The meteorological situation each winter was quite diff erent. Both seasons were cold throughout Dec and Jan. In 1995 a dynami cal warming event increased T in the latter part of Feb but a further cold spell occurred in early Mar. In contrast, the polar vortex remain ed well developed until early Mar 1996, when T increased rapidly. Whil e both winters were extremely cold at 50 hPa, the polar vortex was dee per in Feb 1996 when extremely low T occurred over large areas at 30 h Pa.