Numerical Simulations of Internal Solitary Wave Evolution Beneath an Ice Keel

• Published in: Journal of geophysical research. Oceans 2022-02, Vol.127 (2), p.n/a
• Main Authors: Zhang, Peiwen, Xu, Zhenhua, Li, Qun, You, Jia, Yin, Baoshu, Robertson, Robin, Zheng, Quanan
• Format: Article
• Language: English
• Subjects: Arctic ocean; Climate change; Deformation; Destabilization; Diapycnal mixing; Disintegration; Energy; Energy sources; Evolution; General circulation; Geophysics; Heat flux; Heat transfer; Heat transport; Ice; Ice cover; Ice environments; Ice keels; Internal wave; Internal waves; Latitude; Mixing; Numerical simulations; Oceans; Physics; Polar environments; Sea ice; Shape effects; Simulation; Solitary waves; Turbulent mixing; Undersea; Upper ocean; Warming climate
• ISSN: 2169-9275; 2169-9291
• DOI: 10.1029/2020JC017068

The deformation and evolution of internal solitary waves (ISWs) beneath an ice keel can enable potential diapycnal mixing and facilitate upper ocean heat transport, despite a poor understanding of the underlying physics and energetics of ISWs in Polar environments. This study aims to understand the dynamic processes and mixing properties during the evolution of ISWs beneath ice keels in the Arctic Ocean using high‐resolution, non‐hydrostatic simulations. Ice keels can destabilize ISWs through overturning events. Consequently, the initial ISW disintegrates and transfers its energy into secondary smaller‐scale waves. During the ISW‐ice interaction, ISW‐induced turbulent mixing can reach O(10−3) W/kg with a magnitude of resultant heat flux of O(10)W/m. Sensitivity experiments demonstrated that the ISW‐ice interaction weakened as the ice keel depth decreased, and consequently, the resultant turbulent mixing and upward heat transfer also decreased. The ice keel depth was critical to the evolution and disintegration of an ISW beneath the ice keel, while the approximate ice keel shape had little effect. Our results provide an important but previously overlooked energy source for upper ocean heat transport in the Arctic Ocean. Plain Language Summary Internal wave‐driven mixing plays an important role in both ocean general circulation and climate change. Internal waves (IWs) at mid to low latitudes have attracted much attention; however, our understanding of the evolution and physics of IWs in high‐latitude Polar oceans remains limited. This study aims to explore the evolution and energetics of internal solitary waves (ISWs, a kind of high‐frequency IW) in the ice environment of the Arctic Ocean using non‐hydrostatic 2D simulations. The results reveal the destabilization process of an ISW during its interaction with an ice keel (undersea portion of ice cover). During the ISW‐ice interaction in the Arctic Ocean, ISW‐induced turbulent mixing can reach O(10−3) W/kg with a magnitude of resultant heat flux of O(10) W/m. Thus, the ISW‐ice interaction provides an important, but previously overlooked, energy source for upper ocean heat transport in the Arctic Ocean. Key Points Destabilization and disintegration of internal solitary waves (ISWs) under ice keels can radiate energy into secondary waves Turbulent mixing and vertical heat flux are significantly enhanced during ISW‐ice interactions The ISW‐ice interaction and resultant heat transfer weaken with the shrinking of