Beschreibung
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.
Autorenporträt
Inhaltsangabe1. The Subject and Methods of Research.- 1.1. Historical summary of the development of ideas regarding oceanic fronts.- 1.2. Definitions, terminology and criteria.- 1.3. Classification of frontal zones and fronts of the World Ocean.- 1.4. Modern methods of frontal research.- 2. General Physical Description of the Phenomenon.- 2.1. How frequently are fronts encountered in the ocean?.- 2.2. General background of spatial variability in temperature and salinity near the surface of the ocean.- 2.2.1. Composite spectrum of spatial variability of the temperature field in the ocean.- 2.2.2. Spatial variability of salinity.- 2.3. Main physical parameters of frontal zones and interfaces.- 2.4. On the conditions of frontogenesis in the ocean and in the atmosphere.- 2.5. The concepts of deformation field and frontogenesis.- 2.6. On numerical modelling of oceanic frontogenesis.- 2.7. Problems of general frontal dynamics.- 2.8. Factors controlling the evolution of fronts.- 2.8.1. The effect of wind on near-surface fronts.- 2.8.2. Wave-like instability at fronts.- 2.9. On the two important functions of Ekman boundary layers.- 3. Characteristic Features of Oceanic Fronts.- 3.1. Eddies and fronts in the ocean.- 3.1.1. Frontogenesis in synoptic eddies.- 3.1.2. Eddy generation at fronts.- 3.1.3. Frontal systems of Gulf Stream rings.- 3.2. Peculiarities of coastal upwelling fronts.- 3.3. Salinity fronts originating from river discharge into coastal areas of the ocean.- 3.3.1. Open-sea discharge fronts.- 3.3.2. Estuarine fronts.- 3.4. Coastal fronts with tidal mixing.- 3.5. Surface phenomena of a frontal nature.- 4. Fronts and the Structure of the Ocean.- 4.1. On the multifrontal structure of frontal zones.- 4.2. Thermohaline finestructure near oceanic fronts.- 4.2.1. Characteristics of the thermohaline finestructure of frontal zones.- 4.2.2. The formation, evolution and destruction of frontal intrusions.- 4.3. Characteristic features of the three-dimensional spatial structure of frontal zones (as in the example of the Gulf Stream).- 4.4. Cross-frontal transfer.- 4.4.1. Estimates of double-diffusive heat and salt transport.- 4.4.2. Role of the density increase due to mixing.- 5. Problems for Future Research and the Concerns of Associated Disciplines.- 5.1. Some generalizations.- 5.2. Research on the physics of frontal phenomena in the ocean and associated problems of other disciplines.- 5.3. Future research tasks.- References.
