New weapon to tackle environmental catastrophes

Spring 2012

Managing fallout from environmental disasters like the April 2010 Gulf of Mexico Deepwater Horizon oil spill requires precise tools to predict how the oil will flow. Thanks to work done by Mechanical Engineering Professor George Haller and colleague Josefina Olascoaga, a geophysicist at the University of Miami, such tools now appear within reach.

“People used to attribute oil spill movement to randomness or chaos. But it turns out, when you look at data sets, you can find hidden patterns in the way that water and air move,” Haller says.

During the past decade he has developed mathematical methods to describe these hidden patterns — now broadly called Lagrangian Coherent Structures (LCSs), after French mathematician Joseph-Louis Lagrange.

“The ocean is like a busy city with a network of roads, except that the roads in the ocean are invisible, in motion and transient.”

The method the team developed allows them to detect the cores of LCSs — the equivalent of traffic intersections in an urban environment.

The intersections unite incoming flow from opposite directions and eject the resulting mass of water. When such an LCS core emerges and builds momentum inside a spill, researchers can predict that oil is bound to seep out within the next four to six days. The result: forecasting dramatic changes in pollution patterns that were previously considered unpredictable.

Deepwater Horizon rig fire

Olascoaga’s computational techniques and Haller’s theory for predicting the movement of oil in water have other applications as well, such as predicting the spread of ash in air following a volcanic explosion.

Although Haller wasn’t tracking the movement of spilled oil during the Deepwater Horizon tragedy, he and Olascoaga are confident their new mathematical method will help officials charged with controlling future pollution disasters plan clean-up efforts more effectively.

An abstract that Haller and Olascoaga published explaining their research is available in the Proceedings of the US National Academy of Science.

With files from Katherine Gombay
and Barbra Gonzalez.

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