Horizontal and vertical motions associated with mesoscale (10–100 km) and submesoscale (1–10 km) features, such as fronts, meanders, eddies, and filaments, play a critical role in redistributing physical and biogeochemical properties in the ocean. This study makes use of a multiplatform data set of 82 drifters, a Lagrangian float, and profile timeseries of temperature and salinity, obtained in a ∼1‐m/s semipermanent frontal jet in the Alboran Sea as part of CALYPSO (Coherent Lagrangian Pathways from the Surface Ocean to Interior). Drifters drogued at ∼1‐m and 15‐m depth capture the mesoscale and submesoscale circulation aligning along the perimeter of fronts due to horizontal shear. Clusters of drifters are used to estimate the kinematic properties, such as vorticity and divergence, of the flow by fitting a bivariate plane to the horizontal drifter velocities. Clusters with submesoscale length scales indicate normalized vorticity ζ/f > 1 with Coriolis frequency f and normalized divergence of (1) occurring in patches along the front, with error variance around 10%. By computing divergence from drifter clusters at two different depths, we estimate minimum vertical velocity of (−100 m day⁻¹) in the upper 10 m of the water column. These results are at least twice as large as previous estimates of vertical velocity in the region. Location, magnitude, and timing of the convergence are consistent with behavior of a Lagrangian float subducting in the center of a drifter cluster. These results improve our understanding of frontal subduction and quantify convergence and vertical velocity using Lagrangian tools.

中文翻译：

---

漂移者在阿尔伯兰海中测得的正面会聚度和垂直速度

与中尺度（10-100 km）和亚中尺度（1-10 km）特征有关的水平和垂直运动，如锋面，曲折，涡流和细丝，在重新分配海洋的物理和生物地球化学特性中起着至关重要的作用。这项研究利用了多平台数据集，其中包括82个浮标，一个拉格朗日浮标以及温度和盐度的分布时间序列，这些时间序列是在Alboran海以1-5 m / s的半永久性额叶射流作为CALYPSO（相干拉格朗日路径从从表面海洋到内部）。在大约1m和15m深度下沉的漂流者，由于水平剪切作用，捕获了沿前缘周边排列的中尺度和亚中尺度的环流。漂流器簇用于估计运动学特性，例如涡度和发散，通过将双变量平面拟合至水平漂移器速度来确定流量。亚尺度尺度尺度的星团表明归一化涡度ζ / f  > 1且科里奥利频率f和（1）的归一化散度发生在沿前部的斑块中，误差变化在10％左右。通过计算来自两个不同深度的漂流星团的散度，我们估计水柱上部10 m的最小垂直速度（−100 m day ^-1）。这些结果至少是该区域垂直速度先前估计值的两倍。收敛的位置，幅度和时机与漂泊星团中心的拉格朗日浮子俯冲的行为一致。这些结果提高了我们对额叶俯冲的理解，并使用拉格朗日工具量化了收敛性和垂直速度。