Submesoscale processes are essential in balancing global oceanic energy cascades and stimulating air–sea communications. However, measurements of submesoscale turbulence are still not acquired easily. Based on long-term (2003–2012) shipboard current observations, we obtained direct evidence of considerable submesoscale energization in the Kuroshio, implied by conspicuous spectral characteristics across multiple scales. The submesoscale motions (peak at ∼26 km) exhibited topographically dependent features and typical contrarotating vortex-pair forms for island wakes, indicating footprints of upstream islands and seamounts. The vortex regimes and stability were analyzed using dimensionless parameters. Furthermore, the submesoscale motions radiated energy in the form of near-inertial waves, which exhibited consistent shear structures, and spread widely across the entire strait. These results highlight the role of topography in modulating dynamics by continuously promoting energy cascades into submesoscales, which is expected to be universal for rough topography in the ocean.

中文翻译：

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吐噶喇海峡黑潮推动的亚中尺度过程

亚尺度过程对于平衡全球海洋能量级联和刺激海空通信至关重要。然而，亚介尺度湍流的测量仍然不容易获得。根据长期（2003-2012）船上电流观测，我们获得了黑潮中存在大量次中尺度能量的直接证据，这通过多个尺度上显着的光谱特征来暗示。亚中尺度运动（峰值在~26公里处）表现出与地形相关的特征和岛屿尾迹的典型对转涡旋对形式，表明上游岛屿和海山的足迹。使用无量纲参数分析涡流状态和稳定性。此外，亚中尺度运动以近惯性波的形式辐射能量，表现出一致的剪切结构，并广泛传播到整个海峡。这些结果强调了地形通过不断促进能量级联进入亚尺度来调节动力学的作用，预计这对于海洋中的粗糙地形来说是普遍存在的。