Autonomous Pack Ice Vibration Monitoring System

The characteristics of flexural-gravity wave propagation in Arctic pack ice, including wave speed as a function of frequency and the frequency of peak energy, depend on the spatially averaged ice thickness. Thus a system which records these characteristics can be used to monitor changes in the average thickness of the pack ice. This is vital to understanding and predicting global climate change. Here we propose to design, build, and test a prototype system for monitoring the frequency of pack ice vibrations. The system will consist of a single two-axis tilt sensor, a GPS unit, a data logger, ARGOS satellite telemetry gear, and a solar power system with batteries for winter-over. The system will be tested on a lake in New Hampshire. If possible, the system will then be sent for deployment in the Arctic. Also proposed are investigations into the benefits of more complicated systems consisting of arrays of tilt-sensors and autonomous impact sources. Such a system could monitor both the ice thickness and the ice modulus of elasticity. In Phase 2 several systems would be deployed and we would begin to monitor ice thickness.