Saturday, 15 February 2014
Regency A (Hyatt Regency Chicago)
In this presentation, I 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 -- Arctic amplification -- with changes in the trajectory of the upper-level flow in mid-latitudes. Evidence will be presented that suggests Arctic Amplification may have contributed to an increase in large-scale wave amplitude and slower zonal winds in the upper-level flow, 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 -- some of which appear to be increasing in frequency. New analysis of fields from reanalyses and model output that further supports linkages between Arctic amplification and mid-latitude weather patterns.