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Geoffrey "Jake" Gebbie

MIT/WHOI Joint Program, Physical Oceanography

Physical Oceanography
Advisor: Carl Wunsch
Research interest: Ocean circulation, weather, and climate change
Expected graduation: 2004

In the early 1990s, scientists off of North Africa and Europe placed moorings, floats, and current meters in the sea as part of an oceanography project called the Subduction Experiment, designed to study the mixing of surface water into the deeper ocean. At the same time, the TOPEX/Poseidon satellite was beginning to capture information about the sea surface and ocean temperature.

The result of the two efforts was a mound of data that physical oceanographers and students like Jake Gebbie are still sifting through more than a decade later. Their goal is to understand the role of eddies, currents, and the ocean on long term weather and climate change. "Jake is taking the existing data and blending it with state-of-the-art theoretical models to give us the best possible picture of what was happening in the ocean," said Senior Scientist James Price in the Physical Oceanography Department at WHOI.

For his graduate studies, Jake was challenged to produce an accurate picture of what was happening in a 3,000-mile wide swath of ocean from 1991 to 1993. Jake's numerical modeling work is pioneering, Price said, because it is the first attempt to include information about whirlpool-like underwater eddies swirling in the region.

"Until recently, we could only get glimpses of ocean eddies with shipboard instruments," said Jake. "Ships are too slow and expensive to cover a large area needed to put together a map of a group of eddies." Instead, he said numerical models help produce sophisticated maps that explain what was happening.

"By using a model, he could quantify the role of eddies in the subduction process," said Carl Wunsch, Jake's advisor and a professor of Physical Oceanography at MIT. "Ten years ago, we did not have data or the modeling capability to do this experiment."

When oceanographers took the original data in the early 1990s, Wunsch said they used "three or four moorings, plus a few floats and a ship running around. There wasn't adequate coverage to describe the eddy field." Improved observation, such as those from TOPEX/Poseidon, allowed them to map the eddy field as it evolved through time.

Jake's work is part of a larger climate puzzle being unraveled by oceanographers. He became interested in climate research as an undergraduate student at UCLA because it seemed like the best way he could use his mathematical talents.

"Predicting the climate in the long term can help all sorts of people," ranging from farmers to fishermen to business people, Jake said of his studies in the MIT/WHOI Joint Program. "I was looking for research that could be directly applied."

- Amy E. Nevala

Originally published: December 1, 2003