We know that many events affect the climate on Earth. We usually hear a lot about El Nino and La Nina and their worldwide effects in the press and news. Other phenomena such as the North Atlantic Oscillation and the Arctic Oscillation are discussed much less in the popular press but both these air-sea interactions can have major effects in both North America and Europe. One type of weather event, we rarely hear about is Sudden Stratospheric Warming (SSW). One might ask how can an event in the stratosphere affect the weather at Earth’s surface? Much light was shed on this subject in an article in the June , 2018 issue of EOS (published by the American Geophysical Union). In this article (Online at:
https://eos.org/features/how-sudden-stratospheric-warming-affects-the-whole-atmosphere
The authors (Pedatella et. al.) describe how an SSW can move down from the stratosphere and affect the troposphere – depressing the tracks of extra tropical cyclones southward in the Northern Hemisphere. This can result in very cold temperatures and heavy snow in Eastern North America. The interaction of a SSW with the troposphere is not completely understood. These SSW events occur about six times in a decade.
We have learned a lot in recent years about atmosphere-ocean interactions and about stratosphere-troposphere interactions. However, there remains much more to learn and understand about how the weather on Earth responds to these various phenomena.