Interference Pattern and Propagation of the M2 Internal Tide South of the Hawaiian Ridge

• Published in: Journal of physical oceanography Vol. 40; no. 2; pp. 311 - 325
• Main Authors: RAINVILLE, Luc, SHAUN JOHNSTON, T. M, CARTER, Glenn S, MERRIFIELD, Mark A, PINKEL, Robert, WORCESTER, Peter F, DUSHAW, Brian D
• Format: Journal Article
• Language: English
• Published: Boston, MA American Meteorological Society 01.02.2010
• Subjects: Dynamics of the ocean (upper and deep oceans); Earth, ocean, space; Exact sciences and technology; External geophysics; Physics of the oceans; Hawaiian Ridge; Pacific Ocean; Space remote sensing; energy transfer; Primitive equation; Satellite observation; digital simulation; Measurement in situ; Wave propagation; Wave interference; Source localization; internal waves; tomography; Observation data; Wave generation; Measuring network; altimetry; high resolution
• ISSN: 0022-3670; 1520-0485
• DOI: 10.1175/2009jpo4256.1

Abstract Most of the M2 internal tide energy generated at the Hawaiian Ridge radiates away in modes 1 and 2, but direct observation of these propagating waves is complicated by the complexity of the bathymetry at the generation region and by the presence of interference patterns. Observations from satellite altimetry, a tomographic array, and the R/P FLIP taken during the Farfield Program of the Hawaiian Ocean Mixing Experiment (HOME) are found to be in good agreement with the output of a high-resolution primitive equation model, simulating the generation and propagation of internal tides. The model shows that different modes are generated with different amplitudes along complex topography. Multiple sources produce internal tides that sum constructively and destructively as they propagate. The major generation sites can be identified using a simplified 2D idealized knife-edge ridge model. Four line sources located on the Hawaiian Ridge reproduce the interference pattern of sea surface height and energy flux density fields from the numerical model for modes 1 and 2. Waves from multiple sources and their interference pattern have to be taken into account to correctly interpret in situ observations and satellite altimetry.