4.2 More Observational Evidence Linking Arctic Amplification and Extreme Weather in Mid-Latitudes

Monday, 29 April 2013: 4:00 PM
South Room (Renaissance Seattle Hotel)
Jennifer A. Francis, Rutgers University, Highlands, NJ; and S. Vavrus

In this presentation, we will build on analysis presented in Francis and Vavrus (GRL, 2012) in which mechanisms were proposed and demonstrated that link enhanced warming in the Arctic during recent decades with changes in the trajectory of the upper-level flow in mid-latitudes. Evidence was presented that suggests Arctic Amplification may have contributed to an increase in large-scale wave amplitude and slower zonal winds, both of which favor more persistent weather patterns in mid-latitudes. Prolonged weather conditions are often associated with extreme weather -- such as droughts, cold spells, heat waves, and some flooding events, -- which have become more frequent in recent years. New analysis of fields from reanalyses will be presented that illustrates the response of mid-latitude upper-level flow characteristics to Arctic Amplification, in particular the regional and seasonal variability in large-scale wave propagation speed and wave amplitude that may favor an increase in extreme weather events.
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