Arctic Amplification and Polar Vortex Blizzasters

By June 28, 2014 February 17th, 2015 Arctic, Extreme Weather, Uncategorized

Screen et al., Amplified mid-latitude planetary waves favour particular regional weather extremes, Nature Climate Change, June 22, 2014.

Recent publications tell us that a warmer planet will have more cold extremes over high latitudes and a little south of there (the Great Lakes and northward in the US). This is because of Polar Amplification where polar regions warm twice as fast (or more) than the rest of the world and it supports the occurrence of all of these Polar Vortex Blizzasters we have been seeing  in the Northeast for nearly a decade now.

Mentioned in the paper were: European heat wave in
summer 2003, cold and snowy winters in 2009/10, 2010/11 and
2013/14 in the northeast United States, the Russian heat wave
in summer 2010, the Texas drought of 2011, and the summer
2012 and winter 2013/14 floods in the United Kingdom. Their evaluation did not look at weather events like hurricanes and tornadoes.

Northern Hemisphere weather for 1979 to 2012 was evaluated. The abstract concludes:

Amplification of quasi-stationary waves preferentially
increases the probabilities of heat waves in western North
America and central Asia, cold outbreaks in eastern North
America, droughts in central North America, Europe and
central Asia, and wet spells in western Asia.

Screen lists two other works that support the increase in the magnitude and decrease in the forward speed of planetary waves (the jet stream).

Francis, J. A. & Vavrus, S. J. Evidence linking Arctic amplification to extreme
weather in mid-latitudes. Geophys. Res. Lett. 39, L06801 (2012).

Petoukhov, V., Rahmstorf, S., Petri, S. & Schellnhuber, H. J. Quasiresonant
amplification of planetary waves and recent Northern Hemisphere weather
extremes. Proc. Natl Acad. Sci. USA 110, 53365341 (2013).