Publish Date: September 29, 2017
Article Source: Bulletin of American Meteorological Society
Article Link: www.aer.com/news-events/in-the-news/2017/more-persistent-weak-stratospheric-polar-vortex-states-linked-cold-extremes
In a new research article published online at the Bulletin of American Meteorological Society describing research performed at AER, evidence is provided that colder winter temperatures across the Northern Hemisphere are related to a weakening trend of the polar vortex (PV). The PV is a deep low-pressure center in the upper atmosphere that usually sits over the Pole during the winter months and is encircled or surrounded by a fast-flowing river of air. To the north of the river of air, temperatures are cold and to the south they are mild. When the PV is strong, temperatures are usually mild and when the PV is weak winter weather is often more severe across the mid-latitudes. In the paper, we also show that the trend in a weakening PV is related to atmospheric changes associated with accelerated Arctic warming including melting sea ice and increasing Siberian snow cover. Climate scientists remain polarized on whether accelerated Arctic warming is leading to more extreme weather but this study lends further support that a changing Arctic impacts the weather in surprising ways such as increasing the likelihood of severe winter weather including cold extremes and heavy snowfalls.