On Physical and Dynamical Fronts in the Ocean

Abstract

A review of the works of Yu. Ivanov devoted to the study of the front zones of the world ocean is made. He, in fact, made the transition from the study of mean stationary processes to quasi-periodic and non-stationary. Yu. Ivanov developed a constructive formula to compute the speed of Ekman swap on the field purely zonal wind, which allowed us to track seasonal movements of Antarctic zones of divergence and convergence. Ivanov first introduced the concept of dynamic front as a region of divergence or convergence of the flow, in contrast to the physical front, as the region of maximum horizontal gradients characteristics. Analyzing the equation of vertical diffusion, he shows that the physical fronts are on the periphery of the dynamic fronts. The general map of the location of the main front zones in the Southern ocean was obtained by processing the large-scale observations on the 86 meridian sections. In addition, he compared the position of the selected fronts, with the results of previous studies, in particular,with the works of Deacon and Mackintosh together with B. A. Tareev. Based on the developed method of calculations and the type of atmospheric pressure he developed a simple calculation scheme,which allowed to estimate the speed of vertical flows depending on the distance to the center of the cyclone. Based on typical pressure maps, it is possible to determine the zones in which favorable dynamic conditions for zooplankton accumulations are created. This is also one of the practical applications developed by the method of calculation of the position of the front zones in the ocean.