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To investigate the behavioral characteristics of the water temperature inversion layer (TIL), we used data (KODC) from areas in the Northern East China Sea from 1995 to 2016. Water temperature and salinity surveys were conducted 8820 casts over 22 years. Of these, 1589 water temperature inversion layers were found, and the probability of occurrence was 18.0%. In the Gageo island, probability of TIL occurrence in winter was 25 times higher than in summer. On the other hand, in the south of Jeju Island, summer values were 3.7 times higher than winter values. A T-S diagram analysis shows the components of the water temperature inversion layers. Yellow Sea Cold Water was mainly found in the winter, while Jeju Warm Currents and Tsushima Warm Currents were found in summer. The correlation between the probability of the occurrence of a monthly water temperature inversion layer and the amount of seawater volume transported into the study area was analyzed. The correlation coefficient was higher than r = 0.8 in parts of southern Jeju Island. On the other hand, the correlation coefficient was r = −0.6 in the Gageo Island. The spatial correlation index for the seawater volume transport and the water temperature inversion layer is presented.

Wind-induced near-inertial oscillations (NIOs) have been known to propagate their energy downward and equatorward, yet few observations have confirmed this in tropical regions. Using measurements from a moored ADCP in the tropical northwestern Pacific, we report an energetic NIO event associated with Typhoon Rammasun in May 2008, when an anti-cyclonic warm eddy existed around the mooring site. Our analyses reveal that the anti-cyclonic eddy traps the NIO energy at two layers around 120 and 210 m where the buoyancy frequency show high values. The NIO energy continuously decays at layers below its maximum at 210 m, and disappears at depths below the thermocline. During their propagation from 137 to 649 stretchedmeter depths (equivalent to 100 -430 m), NIOs shift their frequencies from 0.92f to 1.05f probably due to the effective f, which changes its magnitude from smaller to larger than local inertial frequency f in the anti-cyclonic eddy. In addition, their vertical energy propagation becomes faster from 0.17 to 0.64 mm s -1 . Decomposition of downward and upward NIO energy propagation shows that the typhoon-induced NIOs remain 29% of their energy in the upper layer, and transfer 71% to the subsurface layers. Our results suggest that typhoon-induced NIOs interacting with meso-scale eddies can play an important role in providing the energy source available for ocean mixing in the tropical regions.