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Observational Evidence of Surface Wave‐Generated Strong Ocean Turbulence
Author(s) -
Ma Hongyu,
Dai Dejun,
Guo Jingsong,
Qiao Fangli
Publication year - 2020
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2019jc015657
Subject(s) - typhoon , seabed , turbulence , geology , dissipation , turbulence kinetic energy , oceanography , continental shelf , significant wave height , climatology , atmospheric sciences , meteorology , wind wave , physics , thermodynamics
By using an acoustic Doppler velocimeter mounted on the seabed of the continental shelf of the northern South China Sea, high frequency velocity fluctuations were measured for 4.5 days. The turbulent kinetic energy dissipation rate was estimated. During the observation, the strong ocean response to Typhoon Rammasun was recorded to compare the turbulent characteristics before and during the typhoon. The results show that the turbulence near the seabed is mainly generated by the tidal current shear and exhibits a quarter diurnal variation during the period before the typhoon. During the typhoon period, the dissipation rate ε dramatically increased from 1 × 10 −6 to 1 × 10 −2 m 2 s −3 within a short time, and the significant wave height and the surface wave orbital velocity showed the same tendency. This finding suggests that the turbulence is dominantly generated by the surface waves near the seabed.