The Physical Nature and Structure of Oceanic Fronts

1. 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.