Second‐mode internal tides in the East China Sea deduced from historical hydrocasts and a model

Authors

Jae-Hun Park, University of Rhode Island
Magdalena Andres, University of Rhode Island
Paul J. Martin
Mark Wimbush, University of Rhode IslandFollow
D. Randolph Watts, University of Rhode IslandFollow

Document Type

Article

Date of Original Version

2006

Department

Oceanography

Abstract

From historical hydrocasts in the Okinawa Trough region of the East China Sea (ECS), acoustic echo time from 700 dbar to the surface shows a tight relationship with temperature (T) except near the 100–200‐dbar layer. This is caused by 2nd‐ or higher‐mode baroclinic variations. Significant out‐of‐phase correlation between upper and lower layer T from the hydrocasts confirms that 2nd‐mode variations are strong. Furthermore, the 2nd‐mode variations are dominant during the ebb tide period, which suggests they are caused by 2nd‐mode internal tides (ITs) generated at the continental shelf break. For comparison, we investigate historical hydrocasts southeast of the Ryukyu Islands, where no significant 2nd‐mode variations are found. A model simulating the M₂ IT agrees qualitatively with these observations: it predicts relatively strong 2nd‐mode IT energy in the ECS, but weak energy in the region southeast of the Ryukyu Islands.

Citation/Publisher Attribution

Park, J.‐H., Andres, M., Martin, P. J., Wimbush, M., and Watts, D. R. ( 2006), Second‐mode internal tides in the East China Sea deduced from historical hydrocasts and a model, Geophys. Res. Lett., 33, L05602, doi: 10.1029/2005GL024732.

Available at: https://doi.org/10.1029/2005GL024732