The Internet is riddled with videos of monstrous waves that totally wipe out surfers. While these videos can be hilarious – and at times absolutely terrifying – have you stopped to think about the epic waves below the sea surface? Little is known about how these waves, known as “internal waves,” are generated and formed. So, researchers spent seven years tracking some of the world’s largest.
For the study, published in the journal Nature, researchers turned their attention to Luzon Strait on the eastern margin of the South China Sea, where internal waves can reach the height of skyscrapers. Some have been documented reaching heights of up to 170 meters (558 feet) tall and traveling hundreds of kilometers.
While previous studies has looked at the propagation of waves across the South China Sea, researchers say this is the first study to gather substantial in situ data, looking at the exact, original position where internal waves are generated at the Luzon Strait. Scientists have previously found it quite challenging to gather this data, which has caused “persistent confusion regarding the nature of the mechanism of wave generation,” researchers note in the study.
They used satellite imagery to track these internal waves as they formed and moved. Co-author Hans Graber, a professor of ocean sciences from University of Miama, explained in a statement that the radar satellite was able to detect ripples on the surface produced by the current of internal waves.
Researchers found that internal waves are generated daily from internal tides, which get pushed westward by the strong Kuroshio Current. The tides grow larger as the water goes through the Luzon Strait into the South China Sea. Some of the waves in the strait were so powerful that the turbulence they created was 10,000 times that found in the open ocean.
Though the findings paint a “clear physical picture,” researchers note in the study that “some questions remain.” Researchers aren’t yet sure of how the Kuroshio Current affects the wave amplitude and the fraction of energy that is dissipated locally. Answers to these questions will require more sophisticated mathematical modeling.
Research on how internal monster waves form and move is important, as the information gathered from these studies give us a better understanding of how these waves are able to move huge volumes of heat, salt, and nutrients, which fish feed on. This information is particularly important in gaining a better understanding of the global climate and could be useful for industrial fishing operations, researchers say.
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