Wang Yang, Legg Sonya
Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.
Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, USA.
Sci Adv. 2025 May 16;11(20):eadq5963. doi: 10.1126/sciadv.adq5963.
Internal tides have a pivotal role in the climate system as a primary source of mechanical energy for diapycnal mixing, which sustains the global meridional overturning circulation. 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. Observations from Argo floats reveal elevated dissipation in regions where Agulhas rings and internal tides converge, corroborating the simulations.
内潮在气候系统中起着关键作用，是垂向混合机械能的主要来源，维持着全球经向翻转环流。内潮耗散位置的变化会改变海洋环流的气候状态。中尺度涡旋和内潮是海洋能谱中的两个显著峰值，尽管时间尺度不同，但在空间尺度上相互重叠。涡旋如何影响内潮的耗散仍不清楚。通过高分辨率模拟和Argo观测，我们发现像阿古拉斯环这样的强海洋涡旋能够在它们相交的区域耗散内潮，使这些涡旋成为内潮耗散的热点区域。阿古拉斯环促进了内潮能量从稳定的低波数向不太稳定的高波数转移，并随后捕获这些高波数，从而增强了它们的耗散。来自Argo浮标的观测显示，在阿古拉斯环和内潮汇聚的区域耗散增加，证实了模拟结果。
