High-frequency or HF radar is a shore-based remote sensing system used to measure offshore water surface currents by sending a low-power electromagnetic pulse over the water surface. The electromagnetic pulse interacts with surface waves on the lake/ocean and bounces back to the antenna. By measuring the characteristics of the returning pulse we can map the speed and direction of the underlying (near surface) lake currents.

With funding from the Great Lakes Observing System (GLOS) and the State of Michigan Department of Environment, Great Lakes and Energy (EGLE), the Great Lakes Research Center of Michigan Technological University installed two 14-foot CODAR SeaSonde HF radar antenna masts and computer systems, one on each side of the Straits just west of the Mackinac Bridge.

What these two radars observe of the surface currents across the Straits is combined to form hourly maps of surface flow (current speed and direction) across this body of water. These maps provide crucial data that can be used to direct search and recovery efforts, inform ships and smaller vessels of currents, guide sportsmen to optimum fishing sites, and generally help us better understand and manage this critical natural resource.

Explore this growing collection of HF radar videos from Michigan Technological University's Great Lakes Research Center below.