Energy Sources Generation and Energy Cascades along the Kuroshio East of Taiwan Island and the East China Sea

Ru Wang,Ze Liu,Yijun Hou

doi:10.3390/jmse9070692

Abstract

There are multi-spatial-scale ocean dynamic processes in the western boundary current region, so the budget of energy source and sink in the Kuroshio Current area can describe the oceanic energy cycle and transformation more accurately. The slope of the one-dimensional spectral energy density varies between −5/3 and −3 in the wavenumber range of 0.02–0.1 cpkm, indicating an inverse energy cascade in the Kuroshio of Taiwan Island and the East China Sea. According to the steady-state energy evolution, an energy source must be present. The locations of energy sources were identified using the spectral energy transfer calculated by 24 years of Ocean General Circulation Model for the Earth Simulator (OFES) data. At the sea surface, the kinetic energy (KE) sources are mainly within 23.2°–25.6° Nand 28°–29° N at less than 0.02 cpkm and within 23.2°–25° N and 26°–30° N at 0.02–0.1 cpkm. The available potential energy (APE) sources are mainly within 22°–28° N and 28.6°–30° N at less than 0.02 cpkm and within 22.6°–24.6° N, 25.4°–28° N and 29.2°–30° N at 0.02–0.1 cpkm. Beneath the sea surface, the energy sources are mainly above 400 m depth. Wind stress and density differences are primarily responsible for the KE and APE sources, respectively. Once an energy source is formed, to maintain a steady state, energy cascades (mainly inverse cascades by calculating spectral energy flux) will be engendered. By calculating the energy flux at 600 m depth, KE changes from inflow (sink) to outflow (source), and the conversion depth of source and sink is 380 m. However, outflow of the APE behaves as the source.

Highlights

College of Mathematics and Systems Science, Shandong University of Science and Technology, Academic Editor: Marco Petti
Based on the above discussion, the accurate distribution of energy sources was obBased on the above discussion, the accurate distribution of energy sources was obtained, and it was concluded that the wind stress and density differences contribute sigtained, and it was concluded that the wind stress and density differences contribute nificantly to kinetic energy (KE) and available potential energy (APE) source generation, respectively, at the sea surface, but undersursignificantly to KE and APE source generation, respectively, at the sea surface, but underface, the density differences contribute significantly to energy source generation
We found that in the wavenumber range of approximately 0.02 to 0.1 cpkm, the slope of the one–dimensional spectral energy density varies between −5/3 and −3

Summary

Introduction

College of Mathematics and Systems Science, Shandong University of Science and Technology, Academic Editor: Marco Petti. The slope of the one-dimensional spectral energy density varies between −5/3 and −3 in the wavenumber range of 0.02–0.1 cpkm, indicating an inverse energy cascade in the Kuroshio of Taiwan Island and the East China Sea. According to the steady-state energy evolution, an energy source must be present. Once an energy source is formed, to maintain a steady state, energy cascades (mainly inverse cascades by calculating spectral energy flux) will be engendered. The Kuroshio in the northwestern subtropical Pacific, which is frequently affected by eddy–flow interactions, is accompanied by the largest eddy variability among all the currents in the Pacific Ocean. Mesoscale eddies in the Kuroshio region result in the transport of mass, heat and energy within a subtropical gyre that affects the path of the Kuroshio [6]. This paper’s study area (outlined by the solid red lines in Figure 1) encompasses the Kuroshio flow area south of the southern tip of Taiwan and published maps and institutional affiliations

Methods

Results

Discussion

Conclusion