Two large warm water eddies are swirling to the north of the Gulf Stream current in this satellite image recorded with the AVHRR sensor (Advanced Very High Resolution Radiometer) aboard a NOAA satellite on June 11, 1997. Blue colors indicate cooler water, while yellow and orange colors indicate warmer water.
Click on image for full size
Courtesy of the Ocean Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory
The Swirling Water of Ocean Eddies
Sometimes water spins away from a surface ocean current, creating an eddy.
The swirling water of an eddy can be more than 100 km (60 miles) in diameter. The center of some eddies is cool while the center of others is warm. Marine life is sparse in warm water eddies, where the water does not have many nutrients. Cold water eddies are usually full of nutrients and marine life.
Eddies form when a bend in a surface ocean current lengthens and eventually makes a loop, which separates from the main current. The Coriolis effect causes cold water eddies to rotate counterclockwise and warm water eddies to rotate clockwise in the Northern Hemisphere while in the Southern Hemisphere cold water eddies rotate clockwise and warm water eddies rotate counterclockwise. There is evidence that the topography of the ocean floor can help eddies to form too. Once an eddy forms, the swirling waters last for at least a few months.
The satellite image at the left of sea surface temperatures (SST) shows two large circular features above the Gulf Stream current in the Atlantic near the northeast coast of the United States. These are eddies. In this image, surface water is colored depending on its temperature. Cooler water is shown with blue and purple and orange and yellow show warmer water. The orange color of these eddies means that they are warm water eddies. This area of the ocean – the Gulf Stream - tends to have some of the largest and most well defined eddies in the world.
Shop Windows to the Universe Science Store!
The
Spring 2010 issue of The Earth Scientist, focuses on the ocean, including articles on polar research, coral reefs, ocean acidification, and climate. Includes a gorgeous full color poster!
You might also be interested in:
The water at the ocean surface is moved primarily by winds that blow in certain patterns because of the Earth’s spin and the Coriolis Effect. Winds are able to move the top 400 meters of the ocean creating
...more
The winds in the Southeast Pacific mainly blow from south to north. They have a strong effect on the climate in the region and worldwide. The winds in this area get their start with a major flow in the
...more
There are many connections between the ocean and the atmosphere in the Southeast Pacific Ocean. Strong winds blow north along the coast of South America. These winds stir up the ocean. That brings cold
...more
Scientists know that west coasts of Chile and Peru and the Southeastern Pacific Ocean are a very important part of the global climate system. However, they don't completely understand how the oceans, atmosphere,
...more
An aquifer is the name for a layer of rock which is capable of holding a large amount of water. Some layers are better at holding water than others, for example a layer of sandstone can hold a good deal
...more
Carbonate is a name for rocks and minerals which contain a molecule made of both carbon and oxygen known as CO32-. (CO32- is also known as the molecule carbonate). Limestone is an example of a calcium
...more
The deep ocean waters are under pressure and are much colder than layers of the ocean which are closer to the surface. Dissolved carbon dioxide seems to be absent from the deep ocean water and as a result
...more
