Head: Prof. V.I. Byshev

• Composite diagnosis of natural climate variability of the ocean-atmosphere system
  
  
• Numerical modeling of hydrophysical ocean processes
  
  
• Laboratory modeling of eddy structures
  
  
• Reconstruction of climatic hydrophysical fields of the ocean

Based on the long-term moored current meter data, calculations were made of sea currents and temperature in the deep-water and the near-bottom layers of the South Atlantic. The existence of jet quasistationary currents (~ 5-6 cm/sec-1) has been established and the presence of a powerful flow (~ 40 cm/sec-1) in the Vema Fracture zone has been confirmed as being responsible for the south-northward transport of the Antarctic bottom water. Quantitative estimates have been obtained of the spectral structure of the velocity field disturbances and water temperature in the South Atlantic deep-water and near-bottom layers, and their similarity to the structures in other regions of the World Ocean has been shown (Ivanov Yu.A., Professor; Neyman V.G., Corresponding Member of the Russian Academy of Sciences).

The three-dimensional nonlinear sigma model of the World Ocean has been used as a basis for the calculations of barotropic currents caused by tangential wind stress, baroclinic currents generated by heat and moisture fluxes at the ocean surface and currents of the World Ocean formed by wind and thermohaline factors. Analysis of the calculation fields has shown that contribution of the thermohaline factors and wind to the formation of ocean circulation averages 50% for the World Ocean. Kinetic energy has been estimated for the three types of the currents. The calculation results show that kinetic energy of a current formed by a joint effect of wind and the thermohaline factors is 1.5 times greater than the sum total of kinetic energy of the wind barotropic currents and the currents generated by heat and moisture fluxes at the ocean surface. This effect is a result of nonlinear interaction of the baroclinic and the barotropic currents (Ivanov Yu.A., Professor,).

Studies of the thermodynamic regime variability of the deep and the near-bottom waters of the ocean was based on WOCE Data Set. Statistical and spectral analysis of the long-term (a year and more) series of instrumental observations has made possible a conclusion about a dominating contribution of synoptic-scale (20-80 days) disturbances to the full energy both in the surface (0-1000 m) and in the deep-water and the near-bottom (3500-4500 m) layers, the disturbances in the surface and the deep-water layers being comparable in energy level (are of the same order) (Ivanov Yu.A., Professor).

Computations have been completed of horizontal water temperature gradients in the main thermocline from the surface to 1000 m depth in the South Atlantic. Statistical estimates of the distribution of the gradients over the ocean area have been obtained for each month. Thermal fronts have been distinguished at the ocean surface. The novelty of the studies consists in that quantitative estimates of the horizontal structure variability of the climatic fields have been obtained for the first time. Such studies are unknown from oceanographic literature (Galerkin L.I., Candidate of Geographic Sciences).

The second stage has been accomplished in the study of the horizontal structure of water salinity fields with the use of quantitative estimates, continuous in latitude and longitude, based on climatic materials. The use of new methods for obtaining quantitative estimates of internal structure - computations of the horizontal gradients of climatic fields - makes possible getting an objective idea of the variability of the fields by seasons and depth at each point of a region or its parts. The results may also be used for comparing independent estimates of circulation and hydrophysical fields from numerical models (Galerkin L.I., Candidate of Geographic Sciences).