The colors on this image show sea surface height changes, up to 25 cm or 10 inches, associated with these swirling ocean features. Ocean eddies are often found near fast ocean currents. Ocean eddies generally last a few months. They play an important role in transporting heat in the oceans. Also, eddies bring nutrients from below to enhance the growth of the marine life.
Many oceanographers are interested in how much the height of the sea surface changes over time.
Answer Earth's geoid is a calculated surface of equal gravitational potential energy and represents the shape the sea surface would be if the ocean were not in motion. To study the how various factors like ocean circulation and eddies affect the height of our oceans, oceanographers eliminate the height of sea surface caused by gravity. The force is greatest at the poles and least at the Equator. This is because of Earth's appoximately spherical shape. The Coriolis Effect Click on the image at left to see a movie created by the University of Illinois Department of Atmospheric Sciences.