Watch a 1,000-Foot-High Wave Move Across the Ocean
Right now, two research vessels carrying some 40 marine scientists are battling stormy conditions in the Tasman Sea to learn more about gigantic subsurface waves—some 1,000 feet high—that are critical to both ocean health and accurate climate modeling.
These internal ocean waves form, move, and break just like the ones you see crashing at your favorite beach, only they're bigger, slower, and very deep down—so deep that no disturbance may register on the sea surface.
“The wavelength between crests is about 100 miles, and they’re moving at jogging speed,” said Robert Pinkel, professor of oceanography at Scripps Institution of Oceanography in San Diego. “Imagine looking at the rolling hills of Kentucky and suddenly noticing that they’re all kind of jogging towards each other, well, if you put on magic glasses and looked at the ocean, that’s what you’d see.”
These massive internal waves are also responsible for the upwelling that brings to the surface critical nutrients that feed the marine food web, from plankton to blue whales. Scientists suspect that areas with highly active internal wave activity are the healthiest and most productive spots in the oceans.
The Tasman Sea happens to be one these magical spots in the ocean—the site of the largest and most focused internal waves on the planet, triggered by the interaction of large tides and an underwater mountain chain off the south coast of New Zealand. The subsequent undersea wave takes about one week to move its skyscraper-sized bulk across the 1,500 miles to the southeast coast of Tasmania, where it detonates on the continental shelf.
It’s what happens next that most interests these scientists.
“Here we’ll see the whole life cycle of these waves—the birth, the middle age, and eventual decay,” said Amy Waterhouse, a Scripps postdoctoral scholar, reached by Skype in Hobart, Tasmania. “The one last question is where do they go to lose all their energy.”
Knowing the answer to that will give climate modelers a far greater degree of confidence in their forecasting.
Pinkel likens this knowledge gap to the early days of medicine. “People could see big arteries with red blood and blue blood coming back to the heart, but they didn’t know there were capillaries connecting the two,” he said. “Completing that circuit correctly is a key part of making climate models work.”
“The ocean is huge and things change quickly,” said Matthew Alford, a Scripps professor of oceanography, reached by satellite phone aboard the Roger Revelle. “Even with two vessels, fifteen moorings, and 40 kilometers of wire, it’s still going to be a challenging problem. The seafloor is really complex here, with slopes, ridges, really strong currents, and eddies. Our work is cut out for us.”
These two boats—the Revelle, a Scripps research vessel, and the Falkor, a Schmidt Ocean Institute vessel—will work in concert through March in the Tasman Sea to collect massive amounts of data on this little understood phenomena of what Pinkel calls “slow motion violence.”
Despite 50-knot winds, the crew of the Revelle has planted 15 moorings in the ocean floor studded with 400 sensors and instruments.
The two ships will next begin a methodical process of gathering real time data from a series of fixed coordinates with additional sensor systems lowered over the side of the boats. When added to the data collected from the moorings, the team hopes to construct the clearest picture of internal waves to date.
“It’s like taking the lid off the treasure chest for the first time,” said Pinkel. “We’re getting the very first view of what’s going down there in the supposedly quiescent depths of the ocean.”