Long-period variability of ocean circulation at different intensity of wind impact

A.B. Fedotov 

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

E-mail: fedotov57@mail.ru

DOI: 10.33075/2220-5861-2020-4-29-34

UDC 551.465.553

Abstract:

   Within the framework of a numerical model of a two-layer ocean with the depth of layers corresponding to average oceanic conditions, the evolution of large-scale circulation under the action of an external vorticity flow of different intensity with constant dissipation parameters is studied. The characteristic time scales of long-period oscillations of current energy at different values of wind load, jet flow parameters, and the time-average level of total energy in the mode of long-period oscillations at different wind intensity are analyzed. In numerical experiments it is shown that with increasing intensity of wind influence the structure of the currents changed increasing the intensity of the main jet stream and the simultaneous weakening of the effect of fluctuations in the main jet streams in the meridional direction, with the characteristic time of long-period oscillations of a system of currents also reducing.

   During the experiments, considerable attention has been paid to the stability of the of long-period oscillations with a sharp change in external parameters. In order to study this circumstance, a field was chosen as the initial field, the structure of which remained qualitatively the same, but the quantitative characteristics of the external parameters of the wind impact were abruptly changed. Numerical calculations have shown that the characteristics of the flow system change significantly at the initial stage of the experiment, and then a qualitatively old flow system is formed with integral characteristics corresponding to new parameters of external impact, namely, the long-period oscillation mode of the main jet flow, accompanied by the generation of intense vorticities with their subsequent absorption at the Western boundary of the calculated region is preserved.

Keywords: synoptic variability, large-scale variability, wind-forced currents.

To quote: Fedotov, A.B. “Long-Period Variability of Ocean Circulation at Different Intensity of Wind Impact.” Monitoring Systems of Environment no. 4 (December 24, 2020): 29–34. doi:10.33075/2220-5861-2020-4-29-34.

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