Structure and variability of internal tides in Luzon Strait

TitleStructure and variability of internal tides in Luzon Strait
Publication TypeJournal Article
Year of Publication2015
AuthorsPickering A., Alford M., Nash J., Rainville L, Buijsman M., Ko D.S, Lim B.
JournalJournal of Physical Oceanography
Volume45
Pagination1574-1594
Date Published2015/06
Type of ArticleArticle
ISBN Number0022-3670
Accession NumberWOS:000356227700007
KeywordsAtm; circulation; dynamics; generation; hawaiian ridge; internal waves; model; ocean; oceanic; Oceanic variability; Phenomena; philippine sea; propagation; radiation; solitary waves; south china sea; structure; tides; variability; wave observations; waves
Abstract

The Luzon Strait is the generation region for strong internal tides that radiate westward into the South China Sea and eastward into the western Pacific. Intrusions of the Kuroshio and strong mesoscale variability in the Luzon Strait can influence their generation and propagation. Here, the authors use eight moorings and two numerical models to investigate these relationships by quantifying the coherence of the diurnal and semidiurnal internal tides in the Luzon Strait. This study finds that the level of coherence of internal tide generation, energy, and energy flux is quite variable, depending on the specific location within the Luzon Strait. Large-scale spatial patterns in internal tide pressure and velocity exist across the region, shaped by the bathymetry, mean flow, and stratification. Internal tide coherence is lower (<30%) near large gradients in this pattern (predominantly along the eastern ridge), which are shifted by the variable Kuroshio and mesoscale fields. At other locations within the Luzon Strait, the internal tide is largely coherent (>80%), and simple calculations suggest that remote sources of internal tides could account for these small decreases in coherence. To the west of the Luzon Strait (away from the primary generation regions), the model suggests that diurnal internal tide energy is more coherent than semidiurnal.

DOI10.1175/jpo-d-14-0250.1
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