Articles | Volume 21, issue 2
https://doi.org/10.5194/os-21-829-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-21-829-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
22 Apr 2025
Research article |
| 22 Apr 2025
| 22 Apr 2025
Dissipation ratio and eddy diffusivity of turbulent and salt finger mixing derived from microstructure measurements
Jianing Li
College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES), Ocean University of China, Qingdao, China
Physical Oceanography Laboratory, Ocean University of China, Qingdao, China
Sanya Oceanographic Institution, Ocean University of China, Sanya, China
Laoshan Laboratory, Qingdao, China
College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
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The local dissipation efficiency (q) of internal tides (ITs) is usually treated as constant in large-scale ocean models. Our study finds q ranges from 0.3 to 0.7 in the Luzon Strait driven by high-mode ITs breaking, and exceeds 1 around the Nansha Islands driven by far-field ITs converging and scattering. We proposed two parameterizations for q, which capture its regional difference and periodic change and highlight the need to incorporate non-local processes into tidal mixing parameterizations.
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This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
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The local dissipation efficiency (q) of internal tides (ITs) is usually treated as constant in large-scale ocean models. Our study finds q ranges from 0.3 to 0.7 in the Luzon Strait driven by high-mode ITs breaking, and exceeds 1 around the Nansha Islands driven by far-field ITs converging and scattering. We proposed two parameterizations for q, which capture its regional difference and periodic change and highlight the need to incorporate non-local processes into tidal mixing parameterizations.
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Ocean Sci., 20, 241–264, https://doi.org/10.5194/os-20-241-2024, https://doi.org/10.5194/os-20-241-2024, 2024
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Understanding internal tide generation and propagation is crucial for predicting large-scale circulation and climate change. Internal tides are prone to interacting with background currents with similar spatial scales during propagation. This paper investigates the physical mechanism of the interaction between semidiurnal internal tides and an anticyclonic eddy in the northeastern South China Sea using a numerical model with high spatial and temporal resolution.
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Short summary
The Osborn relation is widely used to estimate the diapycnal mixing rate, but its accuracy is questioned due to the assumed constant dissipation ratio (Γ) without identifying mixing types. We identify a salt finger and turbulence in the western Pacific and midlatitude Atlantic, finding that Γ is highly variable and related to turbulence parameters, through which we improve mixing rate estimates. Identifying mixing types and refining Γ are necessary to improve mixing parameterization accuracy.
The Osborn relation is widely used to estimate the diapycnal mixing rate, but its accuracy is...
