We characterize the differences in the upward planetary-scale wave propagation during observed weak polar vortex (WPV) events between heavy- and light-sea-ice years in the Barents-Kara Sea based on a composite analysis for the period of 1979–2015. Upward wave propagation during WPV events in heavy-ice years is dominated by the wavenumber 1 component. In contrast, WPV events occurring in light-ice years are characterized by stronger wavenumber 2 propagation, which is caused by the tropospheric wavenumber 2 response to sea-ice reduction in the Barents-Kara Sea. The above observed features are supported by an Atmospheric General Circulation Model experiment. Thus, under present climate conditions, Arctic sea-ice loss is a possible factor modulating the wave propagation during the WPV events. We also find that the WPV events in light-ice years have stronger stratosphere-troposphere coupling, followed by colder midlatitude surface conditions particularly over Eurasia.
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