Evolution of oceanic circulation theory: From gyres to eddies

Physical oceanography is now entering the eddy-resolving era.Eddies are commonly referred to the so-called mesoscale or submesoscale eddies;by definition,they have horizontal scales from 1 to 500 km and vertical scales from meters to hundreds of meters.In one word,the ocean is a turbulent environment;thus,eddy motions are one of the fundamental aspects of oceanic circulation.Studies of these eddies,including observations,theory,laboratory experiments,and parameterization in numerical models,will be the most productive research frontiers for the next 10 to 20 years,although we have made great efforts to collect data about eddies in the ocean;thus far,we know very little about the three-dimensional structure of these eddies and their contributions to the oceanic general circulation and climate.Therefore,the most important breakthrough may come from observations and physical reasoning about the fundament aspects of eddy structure and their contributions to ocean circulation and climate.