M2 baroclinic tide variability modulated by the ocean circulation south of Japan

Sergey M. Varlamov, Xinyu Guo, Toru Miyama, Kaoru Ichikawa, Takuji Waseda, Yasumasa Miyazawa

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)


We analyze a concurrent simulation result of the ocean circulation and tidal currents using a data-assimilative ocean general circulation model covering the Western North Pacific with horizontal resolution of 1/36° to investigate possible interactions between them. Four sites of active M2 internal tide variability in open ocean (hot spots), such as Tokara Strait, Izu Ridge, Luzon Strait, and Ogasawara Ridge, are detected from both the satellite observation and the simulation. Energy cycle analysis of the simulated M2 baroclinic tide indicates two types of the hot spots: dissipation (Tokara Strait and Izu Ridge) and radiation (Luzon Strait and Ogasawara Ridge) dominant sites. Energy conversion from barotropic to baroclinic M2 tides at the hot spots is modulated considerably by the lower-frequency changes in the density field. Modulation at the two spots (Tokara Strait and Izu Ridge) is affected by the Kuroshio path variation together with the seasonal variation of the shallow thermocline. At the other two sites, influence from changes in the relatively deep stratification through the Kuroshio intrusion into South China Sea (Luzon Strat) and mesoscale eddy activity (Ogasawara Ridge) is dominant in the modulation.

Original languageEnglish
Pages (from-to)3681-3710
Number of pages30
JournalJournal of Geophysical Research: Oceans
Issue number5
Publication statusPublished - May 1 2015

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Oceanography


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