Arctic Sea Ice Reduction and Extreme Climate Events over the Mediterranean Region

• Published in: Journal of climate Vol. 26; no. 24; pp. 10101 - 10110
• Main Authors: Grassi, Barbara, Redaelli, Gianluca, Visconti, Guido
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.12.2013
• Subjects: Arctic Oscillation; Arctic sea ice; Atmospheric circulation; Atmospheric models; Basins; Boundary conditions; Climate; Climate change; Climate models; Climatic extremes; Climatic zones; Climatology. Bioclimatology. Climate change; Cold; Computer simulation; Earth, ocean, space; Exact sciences and technology; External geophysics; Extreme cold; Extreme low temperatures; Extreme weather; Floods; General circulation models; Global climate models; Global warming; Heat; Ice; Ice conditions; Ice cover; Marine; Mediterranean climate; Meteorology; Modelling; Oscillations; Peninsulas; Physics; Physics of the oceans; Precipitation; Reduction; Regional climate models; Regional climates; Sea ice; Sea ice concentrations; Sea ice conditions; Seas; Simulation; Simulations; Statistical significance; Temperature; Theoretical physics; Winter; Arctic Ocean; Barents Sea; Italy; Arctic region; Turkey; Mediterranean Area; Spain; AN, North Atlantic; ANE, Europe, Iberian Peninsula; MED, Italy; PN, Arctic; MED, Greece; Europe, Mediterranean Region; Teleconnection; General circulation models; Extreme event; Occurrence frequency; Regional scope; Climate models; digital simulation; Winter; sea ice; Effect on climate; Polar region; Natural hazards; Mediterranean region; climate change; glacial extent
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/JCLI-D-12-00697.1

During the last decade, Arctic sea ice cover has experienced an accelerated decline that has been suggested to drive the increased occurrence of extremely cold winter events over continental Europe. Observations and modeling studies seem to support the idea that Mediterranean climate is also changing. In this work, the authors estimate potential effects on the Mediterranean Basin, during the winter period, of Arctic sea ice reduction. Two sets of simulations have been performed by prescribing different values of sea ice concentrations (50% and 20%) on the Barents–Kara Seas in the NCAR Community Atmosphere Model, version 3 (CAM3), as representative of idealized present and future sea ice conditions. Global model simulations have then been used to run the Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model, version 4 (RegCM4), over central Europe and the Mediterranean domain. Simulations provide evidence for a large-scale atmospheric circulation response to sea ice reduction, resembling the negative phase of the Arctic Oscillation (AO) and characterized by a wave activity flux from the North Atlantic toward the Mediterranean Basin, during winter months. An increase in the occurrence and intensity of extreme cold events, over continental Europe, and extreme precipitation events, over the entire Mediterranean Basin, was found. In particular, simulations suggest an increased risk of winter flooding in southern Italy, Greece, and the Iberian Peninsula.