Ocean Science

An Emergent Role for Eddies

See allHide authors and affiliations

Science  07 Sep 2007:
Vol. 317, Issue 5843, pp. 1295
DOI: 10.1126/science.317.5843.1295c

Much of the kinetic energy of the ocean is concentrated in the mesoscale region of its energy spectrum, which is populated by structures with dimensions of tens to hundreds of kilometers and durations of tens to hundreds of days. There are two distinct types of mesoscale variability—linear westward-propagating Rossby waves and nonlinear eddies—but it is difficult to distinguish one from the other observationally. Satellites have proven to be the best platform for measuring the extent of these features, and based on data they yielded, the accepted view became that most of the mesoscale variability of the oceans was due to Rossby waves. Now, however, Chelton et al. have used additional multi-satellite altimeter data to show that more than half of the extratropical sea surface height variability that defines these structures is actually due to eddies. The remaining variation is probably due to eddies with shorter lifetimes, methodological error, and other physical processes such as Rossby waves. Because nonlinear eddies can transport momentum, heat, and mass, they can contribute to general circulation and ocean biology in ways that Rossby waves cannot. — HJS

Geophys. Res. Lett. 34, L15606 (2007).

Navigate This Article