Long period swells break up the Canadian Beaufort Sea pack ice in September 2009

摘要

During the summer of 2009, ice observations werernmade using Electromagnetic, Video and Laser sensorsrnmounted on an helicopter that was stationed on thernCCGS Amundsen while she traversed the CanadianrnBeaufort Sea pack ice from August 28 to September 12.rnThe Arctic pack ice encountered was made up of thinrn“rotten” first year ice, 50-75cm thick and thicker secondrnyear ice 2-3m thick containing melt ponds. The pack icerndid not represent an obstacle to the icebreaker whichrnmoved at full speed to well above 75oN latitude (Fig. 1).rnUpon arriving on September 6 at the “Multi-Year Ice”rnstation within the thicker, consolidated pack ice, longrnperiod swells with a period of 13.5sec at the start andrnreducing in time appeared coming from the NW. Theyrnwere present for 2 days and broke up the large 2-3kmrnice floes into smaller floes of less than 100m. The videorncamera and laser mounted on the helicopter documentedrnthe break-up of the floes. Data collected along longrnWest-East flight paths showed that the long periodrnswells, generated by a distant storm, penetrated 350kmrninto the pack ice, breaking up and diverging the pack icernwithout any ridging. This process will enhance thernthermodynamic and dynamic processes of pack ice decayrn(Toyota et al., 2006 and Squire et al., 2009) that shouldrnbe included in ice-ocean climate models.