Airborne Observations of the Distribution, Thickness, and Drift of Different Sea Ice Types and Extreme Ice Features in the Canadian Beaufort Sea

摘要

Extensive airborne electromagnetic (EM) ice thickness surveys have been performed in April 2009, 2011, and 2012 over the Canadian Beaufort Sea with a long-range airplane. These are contributing to the Beaufort Regional Environmental Assessment (BREA) project which gathers ice information in preparation of a regulatory framework for safe and environmental responsible oil and gas production. Results show that the location of the multiyear ice edge can be very variable from year to year. Multiyear ice modal thicknesses ranged between 3.0 and 3.7 m. The seasonal ice zone had very variable ice thicknesses depending on the amount and age of ice formed in coastal polynyas and leads throughout the winter. However, we gathered enough data to show that modal first-year ice thicknesses of 2.0 to 2.2 m emerge if profiles are long enough, which can be considered the most representative first-year ice thickness estimate in the Canadian Beaufort Sea in April. However, in the seasonal ice zone also regions with heavily deformed ice thicker than 10 m, and occasional multiyear hummock fields of similar thicknesses occur. Results suggest that multiyear hummock fields may not comprise the thickest ice as they are affected by melt during the summer. Two ice islands had thicknesses between 20 and 30 m. Our results suggest a melt rate of ice islands of 10 m per year in the Southern Beaufort Sea. Ice thickness surveys were complemented by the analysis of satellite radar data and tracking of ice features by means of GPS beacons. We demonstrate that all these activities combined comprise a powerful tool for a future Arctic sea ice environmental observatory.