title: Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events.
abstract: Persistent episodes of extreme weather in the Northern Hemisphere summer have been shown to be associated with the presence of high-amplitude quasi-stationary atmospheric Rossby waves within a particular wavelength range (zonal wavenumber 6-8). The underlying mechanistic relationship involves the phenomenon of quasi-resonant amplification (QRA) of synoptic-scale waves with that wavenumber range becoming trapped within an effective mid-latitude atmospheric waveguide. Recent work suggests an increase in recent decades in the occurrence of QRA-favorable conditions and associated extreme weather, possibly linked to amplified Arctic warming and thus a climate change influence. Here, we isolate a specific fingerprint in the zonal mean surface temperature profile that is associated with QRA-favorable conditions. State-of-the-art ("CMIP5") historical climate model simulations subject to anthropogenic forcing display an increase in the projection of this fingerprint that is mirrored in multiple observational surface temperature datasets. Both the models and observations suggest this signal has only recently emerged from the background noise of natural variability.
authors.affiliation: Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, PA USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Mann
authors.affiliation: Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Rahmstorf
authors.affiliation: Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Kornhuber
authors.affiliation: Department of Earth and Environmental Sciences and Large Lakes Observatory, University of Minnesota Duluth, Duluth, Minnesota, USA.
authors.forename: Byron A
authors.initials: BA
authors.lastname: Steinman
authors.affiliation: Department of Meteorology and Atmospheric Science, Pennsylvania State University, University Park, PA USA.
authors.forename: Sonya K
authors.initials: SK
authors.lastname: Miller
authors.affiliation: Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany.|Institute for Environmental Studies (IVM), VU University Amsterdam, Amsterdam, The Netherlands.
authors.forename: Dim
authors.initials: D
authors.lastname: Coumou