South Atlantic Eddies

The article I chose to do my assignment on was Giant Eddies of South Atlantic Water Invade the North.
The eddies that the article discusses are thought to originated from sharp changes of the direction of the currents, which are called North Brazil Current retroflection eddies. These are observed to the largest eddies in the Atlantic. Scientists and Oceanographers are still uncertain about the causes and effects of these eddies, and about the history and numbers of the eddies, and are still continuing their research today. Between the time period of 1989 to 1992 six retroflection eddies were tracked for the first time, using subsurface floats and surface drifters. As a result of the tracking of these eddies, researchers were able to describe the number, movement, and characteristics of the eddies. Research has found that the deepest loops of an eddie can have diameter up to 250 kilometers, with a depth of 1200 meters, and swirl speeds up to 80 centimeters per second. Research implies that between July to March at least three eddies form, but appear to go away when they approach a 1,000 meter ridge between Barbados and Tobago. Retroflection eddies seem to bring a great deal of volume of water from the South Atlantic northward into the North Atlantic. These eddies move approximately one million cubic meters of water per second, and with three eddies annually this accounts for up to a quarter of the total northward movement of the upper limb of the thermohaline circulation cell. The newly discovered eddies clear up reasons as to why there was a difference between recent data from drifting buoys and the history of ship drifts that showed continuous flow up the coast to the Caribbean.
Oceanographers and scientists have only begun to investigating more deeply into these eddies. Even the information discussed in this article is undeveloped; therefore researchers are still searching for a more clear explanation of the occurrences of these eddies.