The impact of rough topography on behaviors of mesoscale eddies as revealed by submesoscale resolving simulations

Zheng, Kaiwen; Zhang, Zhiwei; Zhao, Wei; Tian, Jiwei

doi:10.1016/j.ocemod.2023.102279

Cited by 1 publication

(1 citation statement)

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“…To further demonstrate the results in the numerical experiments, concurrent moored observations at both local and far‐field locations are needed in the future. Second, the 2D model setup used in this study misses the topographic wakes and submesoscale instabilities in the 3D simulation (Puthan et al., 2022; Ruan et al., 2017; Srinivasan et al., 2017; Zhang X. et al., 2022; Zheng et al., 2023). How the NIWs generated by lee wave breaking interact with the local and far‐field submesoscale processes and how it influences dissipation over topography need to be further studied.…”

Section: Summary and Discussionmentioning

confidence: 99%

Influence of Lee Wave Breaking on Far‐Field Mixing in the Deep Ocean

Zheng,

Zhang,

Yang

et al. 2024

JGR Oceans

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Breaking of internal lee waves generated by flow‐topography interaction is an important driving mechanism for abyssal mixing. By assuming that lee‐wave‐driven mixing is a local process, direct measurements in the past mainly focused on the water column over rough topography. In this study, a non‐local role of lee waves on remote mixing is investigated by using mooring observations in the northwestern Philippine Basin and a series of 2‐dimensional high‐resolution numerical simulations. We find that the breaking of lee waves can generate near‐inertial waves (NIWs) which can propagate away from their generation sites. The NIWs have strong vertical shear which can significantly elevate turbulent dissipation and mixing over remote uneven seafloor. Based on the topography perturbations numerical experiments, we find that for the remote gentle topography with inverse Froude number (Fr−1) between 0 and 0.5, the arrival of upstream NIWs can elevate the near‐bottom layer (0–1,000 m above bottom) dissipation rate and vertical diffusivity by 9.2 and 10.4 times, respectively at 30–50 km away from the NIWs source. For the remote rough topography with Fr−1 between 0 and 4, the corresponding increases are 3.5 and 4.4 times, respectively. The mechanism of upstream NIWs to elevate the downstream dissipation and mixing is through strengthening the shear instability over the far‐field topography, which is associated with NIWs' interactions with the topography and the generated lee waves therein. The results of this study will provide a foundation for improving the mixing parameterizations associated with current‐topography interactions.

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