Research Interests 【 display / non-display 】

Research Interests 【 display / non-display 】

Research Areas 【 display / non-display 】

Research Areas 【 display / non-display 】

Papers 【 display / non-display 】

Papers 【 display / non-display 】

• Revisiting Tide‐Induced Near‐Field Mixing in the Abyssal Ocean

  Toshiyuki Hibiya, Yuki Tanaka, Taira Nagai, Yusuke Hirano , 2024.11

  Geophysical Research Letters

  DOI

• Superinertial Internal Tides Propagating along the Coast: Dynamics and Energetics Revealed through Topographic Modes

  Yuki Tanaka , 2024.11

  Journal of Physical Oceanography

  DOI

• Energy Conversion Rate from Subinertial Surface Tides to Internal Tides

  Yuki Tanaka , 2023.05

  Journal of Physical Oceanography

  DOI

• Stability of a Flow Over Bottom Topography: A General Condition and a Linear Analysis in a Two‐Layer Quasi‐Geostrophic Model With a Possible Application to a Kuroshio Meander

  Yuki Tanaka , 2021.12

  Journal of Geophysical Research: Oceans

  DOI

• Role of tide-induced vertical mixing in the deep Pacific Ocean circulation

  Takao Kawasaki, H. Hasumi, Y. Tanaka , 2021.01

  Journal of Oceanography

  DOI

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Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• 海嶺上における内部風下波の発生を組込んだ乱流ホットスポットのグローバルマッピング

  Project Period (FY)： 2022/04  -  2026/03  Investigator(s): 日比谷 紀之

  Grant-in-Aid for Scientific Research(A)  Co-Investigator  22H00172 

• 狭い海洋フロントにおけるサブメソスケール現象の発生・発達に関わる不安定機構の解明

  Project Period (FY)： 2021/04  -  2025/03  Investigator(s): 田中 祐希

  Grant-in-Aid for Scientific Research(C)  Principal Investigator  21K03664 

• Generation mechanism of tropical instability waves in the equatorial Pacific Ocean and their dissipation mechanism due to internal wave radiation

  Project Period (FY)： 2017/04  -  2022/03  Investigator(s): Tanaka Yuki

  Grant-in-Aid for Young Scientists(B)  Principal Investigator  17K14389 

  In the equatorial Pacific Ocean, there exists a prominent disturbance propagating westward at a speed of ~0.5 m/s with a wavelength of ~1000 km, called tropical instability waves. It is pointed out that a front of tropical instability waves radiates internal waves downward to the ocean interior, which induce turbulent mixing in the thermocline and control the heat transport from the surface to the deep layers, thereby affecting the sea surface temperature and air-sea interaction in the equatorial Pacific Ocean. In this study, the generation mechanism of tropical instability waves in the equatorial Pacific Ocean is clarified in terms of the coupling of two Rossby waves that are trapped in a local potential vorticity gradient in a narrow latitudinal band just north of the equator and are propagating in the opposite directions with each other. Furthermore, the radiation mechanism of internal waves from tropical instability waves is examined in detail.

• Dynamical analysis of diapycnal mixing processes in the ocean toward the formulation of their accurate parameterizations

  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

  Project Period (FY)： 2015/06  -  2020/03  Investigator(s): HIBIYA Toshiyuki

  Other  Co-Investigator  15H05824 

  Existing parameterizations of turbulent mixing in the deep ocean especially over rough bathymetry still have plenty of room for improvement. In this study, we have made improvements on them based on various theoretical and numerical studies and confirmed their validity in terms of the comparison with the results of microstructure measurements which we carried out over the Izu-Ogasawara Ridge using VMP-5500 and/or VMP-X. Besides such improvement of the existing turbulent mixing parameterizations, we have successfully carried out microstructure measurements covering the whole Indonesian Seas, the results of which are expected to provide invaluable information toward the accurate prediction of global climate change.
  We have also proposed a new generation mechanism of Langmuir circulation based on the results of the numerical experiments that take into account the interaction between surface waves and wind-induced current in the sea surface layer.