Mesoscale dipoles compose two counter-rotating mesoscale eddies. They are observed in oceans worldwide and significantly impact the biogeochemical cycle, marine ecosystems, and ocean water transport. This study investigates the evolution of asymmetric dipole eddies based on the satellite altimeter data for the period January 1993–December 2020. The coupling and decoupling of eddy dipoles impact various eddy properties. When the movement of eddies has a dipolar structure, a gentle convergence in parameters (rotational speed, amplitude, eddy kinetic energy, propagation speed, and advective nonlinearity) between the asymmetric dipole eddies is observed–this study refers to it as the “gear-like” process. Kinematic characteristics further indicate that the stronger dipole eddies generally drive the weaker ones to revolve during the “gear-like” process. The revolution direction remains consistent with the rotation direction of stronger dipole eddies. Additionally, eddy size remains relatively stable during the “gear-like” process. The composites of sea level anomaly (SLA) demonstrate that dipole eddies are compressed into a kidney-like shape along the line through their centers. This shape is confirmed by the composites of sea surface temperature anomalies, which closely correspond to the structure of SLA. These findings augment the knowledge regarding the evolution of asymmetric dipole eddies and provide a novel perspective for studying dipoles and eddy-eddy interactions.

中文翻译：

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卫星测高的不对称偶极涡流之间的“齿轮状”过程


中尺度偶极子组成两个反向旋转的中尺度涡旋。它们在世界各地的海洋中被发现，对生物地球化学循环、海洋生态系统和海水运输产生重大影响。本研究根据 1993 年 1 月至 2020 年 12 月期间的卫星高度计数据，研究了不对称偶极子涡流的演化。涡偶极子的耦合和解耦会影响各种涡流特性。当涡流的运动具有偶极结构时，会观察到非对称偶极涡流之间的参数（旋转速度、振幅、涡流动能、传播速度和平流非线性）温和收敛——本研究将其称为“齿轮-喜欢”的过程。运动学特征进一步表明，在“齿轮状”过程中，较强的偶极涡流通常会驱动较弱的偶极涡旋旋转。公转方向与较强偶极涡旋的自转方向保持一致。此外，在“齿轮状”过程中，涡流尺寸保持相对稳定。海平面异常 (SLA) 的合成表明偶极涡流沿着通过其中心的线被压缩成肾状形状。海面温度异常的合成证实了这种形状，它与 SLA 的结构密切对应。这些发现丰富了有关不对称偶极涡流演化的知识，并为研究偶极子和涡旋相互作用提供了新的视角。