Great Lakes researchers are establishing an experimental network of air-pressure sensors around lakes Michigan and Erie to see if they can detect potentially harmful meteotsunami waves, thanks to funding from the University of Michigan-based Cooperative Institute for Great Lakes Research (CIGLR), which receives financial support from the National Oceanic and Atmospheric Administration (NOAA).
Meteotsunamis are storm-driven waves similar in some ways to earthquake-generated tsunamis, though they are far less destructive. About 100 meteotsunamis occur each year on the Great Lakes, though most are one foot or less in height. A meteotsunami is different than a seiche, another type of potentially dangerous wave that occurs in the Great Lakes.
Still, the rapid rise in water levels during a meteotsunami can happen within a few minutes to an hour. Sudden water-level changes can catch people off-guard on piers and beaches, damage waterfront property, disrupt maritime activities, create strong currents, and disrupt operation of shoreline power plants.
The network will include 29 sensors that will look for abrupt air-pressure changes that are often associated with a line of fast-moving summer thunderstorms that can trigger meteotsunami formation. The low-cost system uses a mix of newly installed sensors and existing instruments on research buoys and at shoreline weather stations.
On rare occasions, large Great Lakes meteotsunamis have been known to cause property damage, injuries, and death. In June 1954, a 10-foot wave now believed to be a meteotsunami struck the Lake Michigan shoreline near Chicago, sweeping several people off piers and killing seven.
“Another destructive meteotsunami could happen on the Great Lakes tomorrow, and we’re not ready for it,” says Ed Verhamme of LimnoTech, an environmental engineering and science firm based in Ann Arbor, and the project’s lead researcher. “These rapid-response funds from CIGLR will allow us to move quickly to get the kind of observations needed to alert the public about this frequently overlooked hazard.”
Over the past decade, efforts to develop a meteotsunami warning system have been hindered by the need for real-time, high-frequency data. Each of the sensors in the network will take one air-pressure measurement per minute.
The key to spotting the atmospheric precursors of a meteotsunami is the ability to detect sudden shifts in air pressure that may last just a few minutes. The barometric-pressure sensors on most U.S. government-operated Great Lakes weather buoys and coastal weather stations report real-time measurements once every 10 to 15 minutes, says Philip Chu, a physical scientist at the NOAA and a member of pilot project’s research team.
“One measurement every 10 minutes or longer is just not frequent enough to be able to detect most of these events,” says Chu, who works at the agency’s Great Lakes Environmental Research Laboratory in Ann Arbor. “We need high-frequency measurements, and the instruments must report in real time to offer forecast capability.”
Each sensor sends data to a central data-management system. Ten of the sensors are on existing buoys owned by LimnoTech and various universities, and 10 are at existing shoreline weather stations operated by WeatherFlow Inc. Four new sensors were installed along Wisconsin’s Lake Michigan shoreline this summer, and five more will be installed along lakes Michigan and Erie this fall. The new sensors are being added at places such as boat launches, marinas, and parks.
Data from the stations is already being collected and analyzed. The first test of the full 29-station network is expected to begin next spring. Great Lakes water-level observations and a hydrodynamics model will be used to test the accuracy of the network’s predictions.
If the new project proves successful, the long-term goal would be to incorporate a meteotsunami alert or warning statement into the existing National Weather Service warning system. About 30 million people live along Great Lakes coastlines.
“If we can show that this approach is workable and that we can actually detect meteotsunamis ahead of time, then it could be possible to retrofit or upgrade instruments on most of the coastal stations to get high-frequency, real-time measurements,” says Chu.