title: Stratospheric variability contributed to and sustained the recent hiatus in Eurasian winter warming.
abstract: The recent hiatus in global-mean surface temperature warming was characterized by a Eurasian winter cooling trend, and the cause(s) for this cooling is unclear. Here we show that the observed hiatus in Eurasian warming was associated with a recent trend toward weakened stratospheric polar vortices. Specifically, by calculating the change in Eurasian surface air temperature associated with a given vortex weakening, we demonstrate that the recent trend toward weakened polar vortices reduced the anticipated Eurasian warming due to increasing greenhouse gas concentrations. Those model integrations whose stratospheric vortex evolution most closely matches that in reanalysis data also simulate a hiatus. While it is unclear whether the recent weakening of the midwinter stratospheric polar vortex was forced, a properly configured model can simulate substantial deviations of the polar vortex on decadal timescales and hence such hiatus events, implying that similar hiatus events may recur even as greenhouse gas concentrations rise.
authors.affiliation: The Fredy and Nadine Herrmann Institute of Earth Sciences Hebrew University of Jerusalem Jerusalem Israel.
authors.forename: Chaim I
authors.identifier: 0000-0001-7258-666X
authors.initials: CI
authors.lastname: Garfinkel
authors.affiliation: School of Earth and Environmental Sciences Seoul National University Seoul South Korea.
authors.forename: Seok-Woo
authors.identifier: 0000-0003-2982-9501
authors.initials: SW
authors.lastname: Son
authors.affiliation: School of Earth and Environmental Sciences Seoul National University Seoul South Korea.
authors.forename: Kanghyun
authors.identifier: 0000-0002-0643-5174
authors.initials: K
authors.lastname: Song
authors.affiliation: Department of Earth and Planetary Science The Johns Hopkins University Baltimore Maryland USA.
authors.forename: Valentina
authors.identifier: 0000-0003-2060-6694
authors.initials: V
authors.lastname: Aquila
authors.affiliation: NASA Goddard Space Flight Center Greenbelt Maryland USA.
authors.forename: Luke D
authors.identifier: 0000-0002-5487-2598
authors.initials: LD
authors.lastname: Oman
keywords: Eurasian temperature; hiatus; stratosphere‐troposphere coupling