Second-Mode Internal Tides in the East China Sea Deduced from Historical Hydrocasts and a Model
Journal article (refereed)
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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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 Mu2 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.
- Physical and Dynamic Oceanography