Methodology for estimating the quantitative characteristics of the vortex field surrounding a jet zonal wind current in the ocean

by

A.B. Fedotov 

Institute of Natural and Technical Systems, RF, Sevastopol, Lenin St., 28

E-mail: fedotov57@mail.ru

DOI: 10.33075/2220-5861-2025-3-102-108

UDC 551.465.553                              

EDN: https://elibrary.ru/ypkgwa

Abstract:

Within the framework of a numerical model of two-layered ocean with a depth of layers corresponding to average oceanic conditions, a study of the wind evolution of large-scale circulation for various values of the intensity of wind action on the ocean surface has been conducted. The main focus is on the individual properties of the vortex mesoscale field resulting from baroclinic instability of the jet stream in a quasi-geostrophic numerical model of oceanic circulation. The methology is based on the use of analogues of the kurtosis of a random field, since the fourth powers of the field values are calculated here. This methodology is extremely sensitive to changes in field values, including the intensity of the vortices themselves during evolution. The paper proposes a method for analyzing the vortex field using spectral filtering of harmonics of the long-wavelength part of the spatial spectrum. The filtering scale is selected empirically. After filtering, the fields in the physical space are restored separately using long-wave and short-wave harmonics. Experiments are carried out for five values of wind intensity. A method for estimating the number of vortices surrounding a jet stream is proposed, and the dependence of the number of vortices on the intensity parameter of the wind effect on the upper ocean layer is constructed.

Кeywords: synoptic variability, large-scale variability, wind-forced currents, vortices

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