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Polar Vortex Disruptions by High Latitude Ocean Warming
  • Mostafa E Hamouda,
  • Alice Portal,
  • Claudia Pasquero
Mostafa E Hamouda
Department of Civil and Environmental Engineering, Massachusetts Institute of Techonology

Corresponding Author:

Alice Portal
Institute of Geography, Oeschger Centre for Climate Change Research, University of Bern
Claudia Pasquero
Department of Earth and Environmental Sciences, University of Milan-Bicocca

Abstract

Mid-latitude extreme cold outbreaks are associated with disruptions of the Polar Vortex, which often happen abruptly in connection to a Sudden Stratospheric Warming. Understanding Global Warming (particularly Arctic Amplification) impacts on forecasting such events is challenging for the scientific community. Here we apply clustering analysis on the Northern Annular Mode to identify surface precursors and the governing mechanisms causing polar vortex disruption events. Two clusters of breakdown emerge; 65% of the events are associated with high latitude ocean warming, expressed as North Pacific anomalies and Barents-Kara sea ice loss. Such warming causes large scale modifications of the tropospheric flow that favors a slowdown of the stratospheric vortex. The persistence of ocean surface temperature patterns allows forecasting polar vortex disruptions, and potentially improves prediction skills at the sub-seasonal to seasonal time scales.