Helmholtz-Hodge decomposition-based 2D and 3D ocean surface current visualization for mesoscale eddy detection
Helmholtz-Hodge decomposition-based 2D and 3D ocean surface current visualization for mesoscale eddy detection
复制标题
基于 Helmholtz-Hodge 分解的 2D 和 3D 海洋表面流可视化，用于中尺度涡流检测
DOI：
10.1007/s12650-018-0534-y
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发表时间：
2019
影响因子：
1.7
通讯作者：
Zhilei Liu
中科院分区：
文献类型：
--
作者：
Cuicui Zhang;Hao Wei;Chongke Bi;Zhilei Liu
海洋表层流场（或称海流）的可视化在认识海洋动力学过程中起着重要的作用。它一直是计算机科学和海洋学的研究热点。海洋表层流是海洋大尺度环流（）、中尺度涡旋（10-）、次中尺度过程（1-）等多尺度海洋动力学混合的湍流流场。中尺度涡旋是相对于大尺度海洋环流而言的一种强烈而短暂的运动，对海洋水团、动量和能量的输送具有重要意义。然而，作为探索其动力学机制的基础，它们的检测和识别仍然是一个具有挑战性的问题。一方面，在混合海洋流场中，不同的海洋流相互依赖、相互影响，使得现有的方法很难区分它们。另一方面，中尺度涡旋是海洋上的活跃信号。它们可以随时改变形态和速度。这对现有的作品提出了挑战，以处理它们的边界模糊性和不断的过渡。针对这些问题，提出了一种基于改进的Helmholtz-Hodge分解（HHD）的二维和三维海洋表面流场可视化方法，该方法可广泛应用于中尺度涡动探测。在我们的方法中，HHD将每个混合海洋流场分解为两个分量：旋度分量和散度分量。不同的海洋流动可以由这两个分量独立地表示。此外，为了提高涡流识别的性能，同时揭示海洋流动的三维结构，HHD将二维海洋流场转换为三维势面。最后，对全球和局部海洋流场（黑海和地中海）进行了综合实验，以验证我们的方法。实验结果证明了该方法的有效性。图形摘要
AbstractOcean surface current (or ocean flow) visualization plays a significant role in the understanding of dynamical processes of ocean. It has been a hot research topic in both computer science and oceanography. Ocean surface current is a turbulent flow field mixing of multi-scale ocean dynamics such as large-scale ocean circulations (), mesoscale eddies (10–), submesoscale processes (1–). Mesoscale eddies, which are strong but short-life movement relative to the large-scale ocean circulations, have great importance on the transportation of ocean water masses, momentum and energy. However, their detection and recognition, which are treated as the foundation of exploring their dynamical mechanisms, is still a challenging issue. For one thing, in the mixed ocean flow field, different ocean flows depended and influence with each other making existing methods difficult to identify among them. For another, mesoscale eddies are active signals on the ocean. They may change their forms and velocities at any time. This challenges existing works to deal with their boundary ambiguity and unremitting transitions. To solve these problems, this paper proposes a novel 2D and 3D ocean surface current visualization approach based on an amended Helmholtz–Hodge decomposition (HHD), which can be widely used for mesoscale eddy detection. In our method, HHD decomposes each mixed ocean flow field to two components: curl component and divergence component. Different ocean flows can be represented by these two components independently. In addition, to improve the performance of eddy identification and to reveal the 3D structure of ocean flows simultaneously, HHD transforms the 2D ocean flow field to 3D potential surfaces. Finally, comprehensive experiments are performed on both global and local ocean flow field (Black Sea and Mediterranean Sea) calculated from satellite maps of sea level anomaly to verify our method. Experimental results demonstrate the good effectiveness of our method.Graphical abstract