Climate researchers at the University of Graz, working together with partners from the Chinese Academy of Sciences, have found that the duration of sudden warming events in the polar stratosphere during winter has increased by around 50 per cent since the 1980s.

In the stratosphere, at altitudes of over 20 kilometres, polar temperatures north of Europe periodically shoot up in explosive bursts. Meteorological data from international weather services shows that the air there can warm from below minus 60 degrees Celsius to above zero within just a few days. This happens on average once a year during the winter months and typically lasts around one to two weeks. Climate researchers at the University of Graz, together with partners from the Chinese Academy of Sciences, have investigated how these wintertime "hot flushes" have developed over recent decades.

"Using a new method, we found that the duration of sudden stratospheric warming events has increased by around 50 per cent since the 1980s," reports Gottfried Kirchengast, lead author of the study, which has been published in the journal Atmospheric Chemistry and Physics. Since the temperature rise in this layer of the atmosphere is accompanied by a massive weakening of the rotating polar vortex, it also influences winter weather at our latitudes.

Find out more at: news.uni-graz.at