在阿尔及利亚海盆欧拉诊断和根据测高计算的有限尺寸李雅普诺夫指数之间的比较
Comparison between Eulerian diagnostics and finite-size Lyapunov exponents computed from altimetry in the Algerian basin
摘要：
表面电流的传输和混合特性可以从高度测量数据检测欧拉和拉格朗日诊断。与欧拉诊断相比，拉格朗日工具，如本地李雅普诺夫指数的优势，利用空间和时间的变化的速度场，并在原则上能够揭开子网格丝产生的混乱搅拌。然而，由于测高产品的不确定性和分辨率，以及地球化学示踪剂的非被动性质，人们可能会怀疑这种理论上的优势在实际数据、中尺度和亚中尺度分析中是否具有实际意义。在这里，我们比较的能力，标准欧拉诊断和有限大小的李雅普诺夫指数检测瞬时和气候输送和混合属性。通过与海面温度模式的比较，我们发现，这两个诊断提供了类似的结果缓慢演变的漩涡，如第一阿尔沃兰环流。然而，李雅普诺夫指数也能够预测沿阿尔及利亚流和巴利阿里深海平原上方发生的（亚）中尺度对流过程。在海面温度模式中也观察到这种细丝，但有些不匹配。气候的李雅普诺夫指数没有表现出任何紧凑的关系与其他欧拉诊断，揭示了不同的结构，即使在流域尺度。我们的结论是，可以通过重新处理现有的测高数据与拉格朗日工具，洞察（分）中尺度搅拌过程相关的示踪剂观测和补充传统的欧拉诊断，检测到的对流动力学。
英文摘要：
Transport and mixing properties of surface currents can be detected from altimetric data by both Eulerian and Lagrangian diagnostics. In contrast with Eulerian diagnostics, Lagrangian tools like the local Lyapunov exponents have the advantage of exploiting both spatial and temporal variability of the velocity field and are in principle able to unveil subgrid filaments generated by chaotic stirring. However, one may wonder whether this theoretical advantage is of practical interest in real-data, mesoscale and submesoscale analysis, because of the uncertainties and resolution of altimetric products, and the non-passive nature of biogeochemical tracers. Here we compare the ability of standard Eulerian diagnostics and the finite-size Lyapunov exponent in detecting instantaneaous and climatological transport and mixing properties. By comparing with sea-surface temperature patterns, we find that the two diagnostics provide similar results for slowly evolving eddies like the first Alboran gyre. However, the Lyapunov exponent is also able to predict the (sub-)mesoscale filamentary process occuring along the Algerian current and above the Balearic Abyssal Plain. Such filaments are also observed, with some mismatch, in sea-surface temperature patterns. Climatologies of Lyapunov exponents do not show any compact relation with other Eulerian diagnostics, unveiling a different structure even at the basin scale. We conclude that filamentation dynamics can be detected by reprocessing available altimetric data with Lagrangian tools, giving insight into (sub-)mesoscale stirring processes relevant to tracer observations and complementing traditional Eulerian diagnostics.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
