Large-scale, realistic laboratory modeling of M2 internal tide generation at the Luzon Strait

TL;DR

This study uses large-scale laboratory modeling to investigate the generation mechanism of M2 internal tides at the Luzon Strait, revealing that a broad, coherent internal tide is shaped by the overall ridge geometry rather than localized features.

Contribution

The paper demonstrates that the M2 internal tide in the Luzon Strait is primarily generated by the overall ridge geometry, using carefully scaled laboratory experiments matching ocean parameters.

Findings

A broad, coherent M2 internal tide is radiated into the South China Sea.

The internal tide steepens as it propagates, not generated by localized features.

Laboratory results match ocean scenario parameters.

Abstract

The complex double-ridge system in the Luzon Strait in the South China Sea (SCS) is one of the strongest sources of internal tides in the oceans, associated with which are some of the largest amplitude internal solitary waves on record. An issue of debate, however, has been the specific nature of their generation mechanism. To provide insight, we present the results of a large-scale laboratory experiment performed at the Coriolis platform. The experiment was carefully designed so that the relevant dimensionless parameters, which include the excursion parameter, criticality, Rossby, and Froude numbers, closely matched the ocean scenario. The results advocate that a broad and coherent weakly nonlinear, three-dimensional, M2 internal tide that is shaped by the overall geometry of the double-ridge system is radiated into the South China Sea and subsequently steepens, as opposed to being generated by a particular feature or localized region within the ridge system.