batch_auto_20260713 202607131256465730 BOEM ESP geoESPIS ESPIS@boem.gov Bureau of Ocean Energy Management Measuring Wave Forces Along Alaska’s Coastal Sea Ice College of Fisheries and Ocean Sciences University of Alaska Fairbanks We designed, built, tested, and deployed portable sensors that measured motion on Chukchi Sea landfast ice and Beaufort Sea drifting sea ice. Our purpose was to acquire information about sea ice motion, forced by winds, waves, or ice-ice interaction, and determine how such motion is related to the formation, decay, and detachment of landfast ice. A key goal is identifying sea ice motion that could be used predictively as part of an early-warning system for landfast ice breakout events, a significant human hazard along the northern coast of Alaska. To meet our objectives, we developed three prototype sensor systems, two using the Vectornav VN-100 Inertial Measurement Unit and one using the Seaview Systems, Inc., SVS-603 wave sensor. Laboratory and field tests led to the production of a sensor (Ice Wave Rider) that acquired more than 9,000 hours of data at 10 Hz, mostly from locations on stable ice in Elson Lagoon, Alaska, from quasi-stationary landfast ice north and west of Utqiagvik, Alaska, and from drifting ice in the Beaufort Sea accessed through the U.S. Navy ICEX2018 and ICEX2020 campaigns. The acquired data consists of vertical and horizontal acceleration and the attitude heading references yaw, pitch, and roll. The measurements can be characterized broadly as "jolts" where ice-ice collisions produced large, shortlived spikes in horizontal and vertical accelerations, "rumbles" where ice-ice interaction associated with ridge formation or ice-ice grinding lasted for minutes or longer, and wind-forced periodic motion identified as waves in ice. Wave signals in the 2020 Ice Wave Rider data showed frequencies consistent with the dispersion relationship expected for waves under an ice cover treated (mathematically) as an elastic plate. For specific wind speeds and ice thicknesses, resonance conditions may occur where the wave energy cannot propagate away, causing the local wave amplitude to grow. Detecting the conditions that permit resonance may be important to forecasting breakout events, understanding the evolving shape of the ice edge, and predicting the timing of seasonal ice breakup. 311000 U.S. Department of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program https://doi.org/10.13039/100012475 M16AC00006 10.67297/9A1DAD https://boem.gov/awardpages/100141