Natural variation: Warm North Atlantic Ocean promotes extreme winters in US and Europe >>The extreme cold weather observed across Europe and the east coast of the US in recent winters could be partly down to natural, long-term variations in sea surface temperatures, according to a new study. Researchers have shown that a phenomenon known as the Atlantic Multidecadal Oscillation (AMO) (a natural pattern of variation in North Atlantic sea surface temperatures that switches between a positive and negative phase every 60-70 years) can affect an atmospheric circulation pattern, known as the North Atlantic Oscillation (NAO), that influences the temperature and precipitation over the Northern Hemisphere in winter. >>Responding to the extreme weather that gripped the eastern coast of the US this winter, Unlike the 2012/2013 winter, this winter had rather low values of the AMO index and the pattern of sea surface temperature anomalies was not consistent with the typical positive AMO pattern. Moreover, the NAO was mostly positive with a relatively mild winter over Europe. Therefore it is unlikely that the positive AMO played a defining role on the east coast of the US, although further work is necessary to answer this question. >>Such an event is consistent with the large internal variability of the atmosphere, and other external forcings may have played a role.
Posted on: Wed, 02 Apr 2014 15:21:16 +0000
Trending Topics
Recently Viewed Topics
© 2015