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Semidiurnal Internal Tide Incoherence In The Equatorial Pacific

Title: Semidiurnal Internal Tide Incoherence In The Equatorial Pacific.
Name(s): Buijsman, Maarten C., author
Arbic, Brian K., author
Richman, James G., author
Shriver, Jay F., author
Wallcraft, Alan J., author
Zamudio, Luis, author
Type of Resource: text
Genre: Journal Article
Journal Article
Date Issued: 2017-07
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: The jets in the equatorial Pacific Ocean of a realistically forced global circulation model with a horizontal resolution of 1/12.5 degrees cause a strong loss of phase coherence in semidiurnal internal tides that propagate equatorward from the French Polynesian Islands and Hawaii. This loss of coherence is quantified with a baroclinic energy analysis, in which the semidiurnal-band terms are separated into coherent, incoherent, and cross terms. For time scales longer than a year, the coherent energy flux approaches zero values at the equator, while the total flux is similar to 500 W/m. The time variability of the incoherent energy flux is compared with the internal-tide travel-time variability, which is based on along-beam integrated phase speeds computed with the Taylor-Goldstein equation. The variability of monthly mean Taylor-Goldstein phase speeds agrees well with the phase speed variability inferred from steric sea surface height phases extracted with a plane-wave fit technique. On monthly time scales, the loss of phase coherence in the equatorward beams from the French Polynesian Islands is attributed to the time variability in the vertically sheared background flow associated with the jets and tropical instability waves. On an annual time scale, the effect of stratification variability is of equal or greater importance than the shear variability is to the loss of coherence. In the model simulations, low-frequency equatorial jets do not noticeably enhance the dissipation of the internal tide, but merely decohere and scatter it.
Identifier: FSU_libsubv1_wos_000409893600005 (IID), 10.1002/2016JC012590 (DOI)
Keywords: model, baroclinic tides, deep-ocean, hawaiian ridge, philippine sea, gravity-waves, gulf-stream, luzon strait, ocean general-circulation, satellite altimetry
Publication Note: The publisher's version of record is available at
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Host Institution: FSU
Is Part Of: Journal of Geophysical Research-Oceans.
Issue: iss. 7, vol. 122

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Buijsman, M. C., Arbic, B. K., Richman, J. G., Shriver, J. F., Wallcraft, A. J., & Zamudio, L. (2017). Semidiurnal Internal Tide Incoherence In The Equatorial Pacific. Journal Of Geophysical Research-Oceans. Retrieved from