Stratospheric‐mesospheric midwinter disturbances: A summary of observed characteristics

Abstract

The midwinter temperature changes in the mesosphere and stratosphere are described, using conventional and satellite data. It is shown that over the northern hemisphere the so‐called stratospheric midwinter warmings extend into the upper mesosphere. The differences between both hemispheres are pointed out. The activity of the planetary‐scale waves during the last 16 northern winters and the importance of the amplification of height wave 1 before the beginning of a major warming are discussed. It is shown that during the northern winters the structure of the quasi‐stationary waves shows an irregular interannual variability that can be connected with the variability of the polar stratospheric temperatures. In contrast, the southern stratospheric winters are rather regular.