Focusing of internal tides by near-inertial waves

Details

• Journal Title:
  Geophysical Research Letters
• Personal Author:
  Cuypers, Y. ; Bouruet‐Aubertot, P. ; Vialard, J. ; McPhaden, M. J.
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research)
• Description:
  The refraction of internal waves by lower-frequency near-inertial waves has been predicted theoretically, but never observed before. Here, we report observations of semi-diurnal internal tides generated by the rough topography of the Central Indian Ridge, in the presence of a strong, lower-frequency near-inertial wave field generated by a tropical storm. The semi-diurnal internal tide energy is trapped within upward propagating bands with a periodicity close to the inertial period. A ray-tracing model suggests that this trapping results from the internal tide refraction by the shear associated with near-inertial waves. This yields a strong increase of the internal tide energy and shear in space-time regions where the background flow focuses the rays, leading to the formation of caustics. This mechanism may increase vertical mixing generated by baroclinic tides in the vicinity of mid-ocean ridges in tropical regions.
• Source:
  Geophysical Research Letters, 44(5), 2398-2406.
• DOI:
  https://doi.org/10.1002/2017GL072625
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:32aced1201476171d449cdd14a70eecd9108f9e3c96a77ab3bc4d53880fb956c
• Download URL:
  https://repository.library.noaa.gov/view/noaa/16105/noaa_16105_DS1.pdf
• File Type:
  [PDF - 5.09 MB ]