Surf’s Up: MIT Helps Measure Largest Waves Ever Documented

Underwater photo via Shutterstock

The latest study out of MIT has it all: A professor named Peacock; autonomous underwater vehicles zipping around the South China Sea; seafaring scientists braving the elements in the name of research; and waves so large that they’re actually causing the moon to recede from Earth ever so slightly.

Here’s what you need to know: A research team that included MIT’s Thomas Peacock built and deployed intricate contraptions deep in the turbulent South China Sea in hopes of measuring the scale of “internal waves,” and following the lifecycle of these beasts from “cradle to grave.”

To do so, Peacock tells Boston that the team attached resilient buoys to long and strong cables. The other end was attached to some very heavy weights that plunged down more than 3,000 meters to the ocean floor in some areas. An array of instrumentation ran along each cable, taking constant measurements at various depths. To capture additional information on the surrounding waters, the team regularly dispatched autonomous underwater vehicles—Peacock says they looked like “yellow torpedoes with wings”—that cruised around harvesting data points.

What did this ambitious undertaking reveal? Only the “largest waves documented in the global oceans,” as the paper, published in the journal Nature, put it. Some of these waves topped 500 meters.

“Internal waves are the lumbering giants of the ocean,” Peacock says. “They move fairly slowly but they are very large in amplitude and carry a lot of energy.”

These waves aren’t for hanging ten, no matter how agro you are, bro. Internal waves occur below the ocean’s surface. They can travel thousands of miles over the course of weeks before breaking against whatever continental shelf they happen upon. Peacock says it’s not unlike the way a surface wave breaks against the beach.

The study is important for two main reasons. First, understanding how these waves form and move across the oceans is important for engineers who are using underwater vehicles to work on pipelines, deep-sea drilling, and similar projects. Second, the far-reaching influence of these waves on the oceans—they blend together waters of different temperatures and waters with different levels of salt—will allow scientists to refine and improve existing climate models.

Peacock marvels at the scale of the waves and what this years-long pursuit of research revealed. As a side note, he explains that internal waves ultimately come from the tides. The moon has long been receding due to forces associated with the Earth’s tides.  “To cut a long story short, it’s not unreasonable to say internal waves play a role in the moon moving away or receding from the Earth,” he says. “They are big enough that they affect large-scale celestial motions.”