Abstract
ABSTRACTObservations suggest that enhanced turbulent dissipation and mixing over rough topography are modulated by the transient eddy field through the generation and breaking of lee waves in the Southern Ocean. Idealized simulations also suggest that lee waves are important in the energy pathway from eddies to turbulence. However, the energy loss from eddies due to lee wave generation remains poorly estimated. This study quantifies the relative energy loss from the time-mean and transient eddy flow in the Southern Ocean due to lee wave generation using an eddy-resolving global ocean model and three independent topographic datasets. The authors find that the energy loss from the transient eddy flow (0.12 TW; 1 TW = 1012 W) is larger than that from the time-mean flow (0.04 TW) due to lee wave generation; lee wave generation makes a larger contribution (0.12 TW) to the energy loss from the transient eddy flow than the dissipation in turbulent bottom boundary layer (0.05 TW). This study also shows that the energy loss from the time-mean flow is regulated by the transient eddy flow, and energy loss from the transient eddy flow is sensitive to the representation of anisotropy in small-scale topography. It is implied that lee waves should be parameterized in eddy-resolving global ocean models to improve the energetics of resolved flow.
Highlights
The importance of the Southern Ocean in the global circulation and climate is largely attributed to its energetic transient eddy field (Rintoul and Naveira Garabato 2013, and references therein)
The equilibration of the transient eddy field is important because the eddy kinetic energy (EKE) is often used as an indicator of how eddies respond to varying wind stress and regulate the Antarctic Circumpolar Current (ACC) transport and MOC strength
Our results show that the lee wave generation is potentially more important than the turbulent processes in the turbulent bottom boundary layer (TBBL) for the energy loss from the time-mean flow, albeit weaker than that associated with the total flow
Summary
The importance of the Southern Ocean in the global circulation and climate is largely attributed to its energetic transient eddy field (Rintoul and Naveira Garabato 2013, and references therein). We estimate the relative energy loss from the time-mean and transient eddy field in the Southern Ocean (408–658S) due to lee wave generation by applying mean–eddy decomposition to modeled velocity fields.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
