Changes in Arctic sea ice deformation from 2000-2010

Tuesday, 16 December 2014: 9:30 AM
Kim I Martini, University of Washington Seattle Campus, Seattle, WA, United States, Jennifer K Hutchings, University of Alaska Fairbanks, Fairbanks, AK, United States and Ignatius G Rigor, Applied Physics Laboratory University of Washington, Kenmore, WA, United States
Changes in Arctic ice pack deformation between 2000 and 2010 are quantified using triads of drifting buoys to calculate ice shear and divergence. In 2006, an abrupt change in shear magnitude and divergence variance occurred, after which ridging and opening rates increased as did the amplitude of the seasonal cycle of shear and divergence. Deformation peaked during the 2007 extreme minimum summer ice extent and there appears to be a recovery-scale time for the mechanical ice response to this event of at least four years. However, by the end of 2010 the ice pack is still more mobile than prior to the 2006 step change. Increased ice mobility and deformation is likely caused by an increase in the mechanical response to atmospheric forcing and enhanced ice-ocean stress rather than stronger forcing, as wind speeds have not increased during this period. Increased opening rates result in increased areas of lead ice, especially entering summer 2008, that likely preconditioned the ice pack for enhanced melt.