Cold core ring

Cold-core rings are a type of oceanic eddy, which are characterized as unstable, time-dependent swirling ‘cells’ that separate from their respective ocean current and move into water bodies with different physical, chemical, and biological characteristics. Their size can range from 1 mm to over 10,000 km in diameter with depths over 5 km. Cold-core rings are the product of warm water currents wrapping around a colder water mass as it breaks away from its respective current. The direction an eddy swirls can be categorized as either cyclonic or anticyclonic depending on the hemisphere. A counterclockwise movement of water in the Northern hemispheres is cyclonic, but the same counterclockwise movement is anticyclonic in the Southern hemisphere (Yasuda, 2000). Although eddies have large amounts of kinetic energy, their rotation is relatively quick to diminish in relation to the amount of viscous friction in water. They typically last for a few weeks to a year. The nature of eddies are such that the center of the eddy, the outer swirling ring, and the surrounding waters are well stratified and all maintain their distinct properties throughout the eddy’s short time-scale.