The Oil and the Loop Current

 An article today in The Times examines the prospect that oil from the gulf spill could reach the so-called loop current, which could carry it into the Florida Keys and the Atlantic Ocean.

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Institute for Optical Oceanography, College of Marine Science, University of South Florida The oil spill in the Gulf of Mexico as observed from space on Monday.

 

Satellite images shed light on the trajectory of the oil and the current. The one above shows the oil spill as observed from space by the NASA satellites Terra and Aqua on Monday. Using an array of sensors, these satellites detect the spectral reflection of the ocean, allowing a wide variety of observations on things like water temperature and surface features like the oil spill.

The oil spill is pictured in outline, revealing a long tail of oil being dragged away from the site of the Deepwater Horizon oil rig by ocean currents. Responsible for the current is a giant eddy, also known as a cyclone, about 150 miles wide from east to west. It has spun off the much larger loop current, a powerful and unpredictable ocean feature that transports warm water in a clockwise motion from the Yucatán Peninsula into the northern Gulf of Mexico, then south to the Florida Keys and out into the Atlantic.

The thickness of the oil in the tail is unknown. Federal officials have characterized it as a light sheen, while some independent scientists believe it to be considerably thicker. That the tail of oil is easily visible from space is one indication that it may be thicker than a light sheen.

“It’s highly visible in our imagery,” said Nan Walker, an oceanographer with the Earth Scan Laboratory at Louisiana State University, where a separate analysis of the satellite images is being done. “It’s unmistakable. And oil spills, to my mind, aren’t usually that easy to track.”

The next two images show the ocean temperature in the gulf, with an outline of the oil spill overlaid. The dark red bulb directly below the oil spill is the loop current; above it is the cooler and less distinct cyclone.

The first image shows the oil spill, upper left, in relation to the loop current on May 6-7.

 
Institute for Optical Oceanography, College of Marine Science, University of South Florida

The following image shows the oil spill on Monday, with a long tongue of oil snaking out to sea.

(All three images were created by Chuanmin Hu of the Institute for Optical Oceanography at the University of South Florida.)

 
Institute for Optical Oceanography, College of Marine Science, University of South Florida
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