High-Frequency Radar

New to the Great Lakes, high frequency radar gives us a live snapshot of lake surface currents, 24 hours a day.

HF radar measures surface currents like no other platform can: over large areas.

When studying currents, researchers are typically limited to a device that measures only one point in the water.

By capturing extremely detailed, near-surface water direction and speed information, this platform allows observers to:

Locate people or pets during search and rescue operations
Track vessels
Monitor movements of hazardous spills or harmful algal blooms
Understand how water moves through complex waterways, like in the Straits of Mackinac

Photos by Nathan Shaiyan, Michigan Technological University, unless otherwise noted.

Arrows indicate the direction and speed of the surface current. Data collected May 2022.

HF radars are shore-based remote sensing systems made up of antennas, generally used in pairs and placed close to the water’s edge.

The antennas send out high-frequency radio waves that bounce off the water’s surface and back to the antenna. By measuring how the waves bounce back, the radar is able to create a map detailing the speed and direction of surface currents.

Because saltwater allows HF radar to work over much larger areas, coastal waters have long benefited from HF radar, but the Great Lakes are just beginning to use it. Even the reduced range, reaching 10-15 miles in some tests, can be enough for many areas.

The first HF radar in the Great Lakes is located in the Straits of Mackinac where, operated by Michigan Technological University (MTU) researchers Lorelle and Guy Meadows, a single radar pair covers the waters on the west side of the Mackinac Bridge.

Explore the latest video data visualizations from MTU here.

Early tests shows the flow of water through the western end of the Straits of Mackinac. Photo by Lorelle Meadows, Michigan Tech. University

Explore the latest video data visualizations from MTU here.

Interactive Map

Use the map to explore HFR data. Select a date by clicking on the date box in the top left corner. Then, give it a moment to load. Deep winter months may have sporadic data due to ice.

From UGLOS. If no data is showing, it is likely due to ice coverage. Check NOAA Great Lakes Environmental Research Lab for current ice conditions.