Five-meter-high waves have been detected in the middle of the Arctic Ocean by Dr Jim Thomson of the University of Washington and Dr Erick Rogers of the Stennis Space Center’s Naval Research Laboratory.
Example wave model hindcast during the September 2012 storm in Arctic Ocean; the map is centered on the North Pole; the color scale indicates significant wave height from 0 to 5 m. Image credit: Jim Thomson / W. Erick Rogers.
“As the Arctic is melting, it’s a pretty simple prediction that the additional open water should make waves,” said Dr Thomson, who is the first author of a paper published in the journal Geophysical Research Letters.
Using a 600 kHz Nortek Acoustic Wave and Current sensor anchored to the seafloor, about 50 meters below the surface, the researchers measured wave height in the ice-free central Beaufort Sea from mid-August until late October 2012.
Extreme, record-breaking waves – up to 5 meters high – were recorded during the peak of a storm in September 2012.
“Arctic ice used to retreat less than 160 km from the shore. In 2012, it retreated more than 1,600 km. Wind blowing across an expanse of water for a long time creates whitecaps, then small waves, which then slowly consolidate into big swells that carry huge amounts of energy in a single punch,” the scientists explained.
“The size of the waves increases with the fetch, or travel distance over open water. So more open water means bigger waves. As waves grow bigger they also catch more wind, driving them faster and with more energy.”
Dr Thomson added: “warming temperatures and bigger waves could act together on summer ice floes. At this point, we don’t really know relative importance of these processes in future scenarios.”
Waves breaking on the shore could also affect the coastlines, where melting permafrost is already making shores more vulnerable to erosion.
The team now plans to learn how wave heights are affected by the weather, ice conditions and amount of open water in the Arctic Ocean.
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Jim Thomson & W. Erick Rogers. 2014. Swell and sea in the emerging Arctic Ocean. Geophysical Research Letters, vol. 41, no. 9, pp. 3136–3140; doi: 10.1002/2014GL059983
