Huge Spinning Bundles of Warm Water

It turns out war water from the Indian Ocean enters the South Atlantic in separate bundles rather than as a continuous stream.

These warm bundles of water are named Agulhas eddies after the current along the east coast of Southern Africa where they originate. Over the past four years, Astrid van Veldhoven of the Royal Netherlands Institute for Sea Research studied how these eddies move.

Using satellite images, van Veldhoven and his colleagues determined that the Agulhas eddies enter the Atlantic as three-foot high bumps. After observing the eddies close up, scientists described them as large rings of warm water about 180 miles wide and nearly 3 miles deep. They also spin counterclockwise at more than 2 miles an hour.

At the ocean's surface, young eddies are about 41 degrees Fahrenheit warmer than the surrounding Atlantic. Because each bundle carries a huge amount of warm water - about 220,000 cubic miles a pop - Agulhas eddies import a considerable amount of heat into the Atlantic Ocean. The eddies gradually release heat and salt into the Atlantic, dying down once they are about halfway to South America.

This research will improve computer models of global ocean circulation, which are necessary for predicting climate change and the effects of global warming.

--Bjorn Carey

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Credit: Royal Netherlands Institute for Sea Research