Physical Nature and Structure of Oceanic Fronts

During the past several years, research into the frontal divisions of the ocean has been particularly intensive. The significance of this lies not only in the fact that, in the five years from 1976 to 1980, more than 500 papers on this question were published in various journals throughout the world and at least three major international discussions were held (see p. 17). The newness of the discussion of the topic stems from the qualitative reinterpretation of the physical essence of the phenomenon and its role in the ocean, particularly in the processes of mixing and structure formation. While in the past the conventional view of fronts as boundaries between large scale water masses of the ocean only led to the recognition of convenient classi fication limits created by nature itself, there is now a tendency to study oceanic fronts as integral elements of the dynamics of oceanic waters. As we understand it, fronts are being associated more and more with the dynamic and kinematic features which arise when kinetic energy and enstrophy are transmitted through a cascade of scales characterizing various forms of motion of a stratified medium in laterally confined oceanic basins. We are beginning to get a better understanding of the role synoptic-scale oceanic eddies play in the process of frontogenesis in the ocean.