Professor Kevin Speer has contributed to the creation of a new paradigm in the study of oceans. (Photo: Bill Lax/FSU Photographic Services)
Deciphering the mystery of the ocean's relationship to climate change
Wednesday, August 29, 2012, 22:40 (GMT + 9)
A Florida State University (FSU) professor of oceanography has a "new paradigm" for describing how the world's oceans circulate — and with it he may help reshape science's understanding of the processes by which wind, water, sunlight and other factors interact and influence the planet's climate.
Professor Kevin Speer and a colleague recently published a significant paper in the respected journal Nature Geoscience.
Working with John Marshall, an oceanography professor at the Massachusetts Institute of Technology (MIT), Speer reviewed — or essentially synthesized — vast amounts of previous data on ocean circulation (including their own earlier papers). As a result, they have created what Speer calls a new paradigm in the study of ocean currents on a global scale.
Here's how it works: Basically, the oceans, together with the atmosphere, rebalance heat on the planet. The sun shines on the Earth and heats up the tropics more than the poles.
Near the poles, the ocean is cold and the water sinks; near the equator, the surface of the ocean is inviting and warm — and floats on top of the colder deep water.
So the question is this: Where does the water that goes down come back up?
Speer, Marshall and other oceanographers now believe that it comes back up in the Southern Ocean surrounding Antarctica — not as much in the warm oceans as had been previously thought.
"We're not saying that nothing comes up in the rest of the World Ocean, just that the main thrust is in the Southern Ocean," Speer said. "To a large extent it's driven by the wind."
Very strong winds, to be precise.
In the rough waters around Antarctica, sailors call those winds the "Roaring Forties" and the "Furious Fifties." They originate near the Equator, where hot air rises and then is pushed toward the North and South poles by cooler air that rushes in to take its place.
The resulting "eddy-driven upwelling" in the Southern Ocean, as Speer characterizes it, may in fact describe the most important process to date that helps scientists understand the role of the ocean and climate.
The laboratory's equipment includes a large, vintage rotating table designed nearly a half-century ago by the lab's founder, Florida State meteorology Professor Richard Pfeffer. (The device may be old, but it's one of the biggest and best in the US, Speer says). Here students can recreate the ocean's churning and study natural phenomena such as the Antarctic circumpolar current.
Speer and his students have been studying ocean currents thanks to USD 2.5 million in funding from a larger USD 10 million National Science Foundation grant that FSU shares with eight other universities and institutions worldwide. Research has included releasing tracers and floats into the ocean to study the mixing and spreading of currents.