This animation shows daily values of the ocean surface relative vorticity as simulated by the Parallel Ocean Program (POP). Vorticity, which can be thought of as the rate of fluid rotation, is particularly useful for visualizing ocean turbulent flow, highlighting the presence of swirling eddies. A significant amount of the total kinetic energy in the world ocean is attributable to these turbulent motions, making them an important component in balances of energy, momentum, heat, salt, and chemical constituents (such as carbon dioxide) throughout the globe.
Colors in the animation reflect both direction and strength of the vorticity. Green eddies rotate the same direction as the earth and orange eddies rotate the opposite way. Additionally, the darker the color, the stronger the rotation. The strongest eddies are typically associated with instabilities of sea surface currents, such as the Gulf Stream off the eastern coast of the United States, the Agulhas Current off the tip of Africa, and the Kuroshio Current east of Japan. Some of the longest living vortices are created by the Agulhas Current, which can take years to cross the Atlantic Ocean. But what is clear is that there are eddies just about everywhere in the ocean that span quite a range of strengths, sizes, and lifetimes.