Variability of near-inertial internal wave energy in the Kuroshio extension from CPIES array observations

초록

Near-inertial internal waves (NIIWs) play a central role in ocean mixing and energy transfer, and understanding their local variability is essential for quantifying ocean energetics. This study investigates the local drivers of NIIW variability in the Kuroshio Extension System Study (KESS) region using observations from a Current-and Pressure-sensor-equipped Inverted Echo Sounder (CPIES) array deployed over a 600 km by 600 km area, assuming negligible net NIIW flux. We developed an empirical model to quantify the contributions of wind-induced near-inertial energy flux (WNEF), mixed layer depth (MLD), and relative vorticity (zeta), which have dominant influences on NIIW variability, accounting for 39 %, 41 %, and 20 % of the variability, respectively. WNEF and MLD positively correlate with NIIW energy, while zeta shows a negative correlation. These findings highlight the significance of local processes in modulating NIIW energy and improving our understanding of ocean mixing dynamics by transitioning from qualitative to quantitative analysis.

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