Agulhas rings locally enhance dissipation of internal tides

Variations in the location of internal tide dissipation can modify the climatic state of oceanic circulation. Mesoscale eddies and internal tides are two prominent peaks in the ocean energy spectrum, which overlap in spatial scale despite contrasting temporal scales.

How eddies affect the dissipation of internal tides remains unclear. Using high-resolution simulations and Argo observations, we show that strong oceanic eddies, such as Agulhas rings, can dissipate internal tides in regions where they intersect, making these eddies hotspots for internal tide dissipation. The Agulhas rings facilitate the transfer of internal tide energy from stable low wave numbers to less stable high wave numbers and subsequently trap these high wave numbers, thereby enhancing their dissipation.