Operational Longevity of Sea Ice Floes in the Beaufort Sea Using RADARSAT-2 and Sentinel-1 Synthetic Aperture Radar Remote Sensing

Arctic sea ice continually becomes thinner due to the changing polar environment and thus more dynamic and more vulnerable to storms. Meanwhile, operational knowledge of the sea ice condition has become more critical for offshore and marine activities, including scientific campaigns as activity in the Arctic has grown. Most multi-week scientific field campaigns in the Arctic seas are designed as drifting observatories usually hosted on an ice floe predicted to survive a summer melt. This has been the design for the U.S. Navy biennial Ice Exercise (ICEX), the Norwegian Young sea ICE cruise (N-ICE2015), the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in 2019-2020, etc. The United States National Ice Center (USNIC) participates in and provides support for ICEX in the Beaufort Sea. USNIC provides situational awareness and position tracking of the selected sea ice floe and the surrounding area. While ICEX typically takes place during the peak season of Arctic sea ice strength, occurring in March, there is interest in examining the ice floes survivability beyond March in order to accommodate extra weeks of research. To do this, USNIC completed a post-ICEX analysis on the ice floes utilized for 2016, 2018, and 2020 ICEX research. USNIC assessed the survivability of the floes beyond the March timeframe using archived RADARSAT-2 imagery and Copernicus Sentinel-1 imagery distributed by the Alaska Satellite Facility. The imagery, combined with post-mission weather analysis, allowed a determination of the safest cutoff date that scientists and military could safely conduct operations on a multi-year ice floe in the Beaufort Sea. Criteria for the cutoff dates were based on drift speed of the ice, ambient air temperatures, distance from nearest supporting airfields, and presence of surface melt. The results will help planners assess the potential ability to conduct longer campaigns and collect additional measurements during the onset of the melt period when significant feedback mechanisms are at play in the ocean-ice-atmospheric system.