Abstract. A dataset of 85 Lagrangian surface drifter trajectories covering the central North Sea area and the Skagerrak from 2017–2021 of 17 deployments is presented. The data have been quality-controlled, uniformly structured, and assimilated in a standard NetCDF format (https://doi.org/10.1594/PANGAEA.963166, Meyerjürgens et al., 2023a). Using appropriate methods presented in detail here, surface currents were calculated from the drifter position data. Based on a drifter deployment in the Skagerrak, it is demonstrated that the Lagrangian measurements can be converted into an Eulerian representation by calculating mean current velocities. Tidal energy spectra were analyzed separately for the southern and northern areas of the North Sea, and tidal ellipses were calculated to determine the tidal impact on surface currents. Significant differences between the shallow shelf and the deeper areas of the North Sea are evident. While the shallow nearshore areas are dominated by tidal currents, deeper areas such as the Skagerrak record a high mean residual circulation driven by high-density gradients. Measurements using Eulerian approaches and remote sensing methods are restricted in temporal and spatial coverage, in particular, to capture fine-scale dynamics. For this reason, Lagrangian measurements, to a large extent, provide new insights into the complex submesoscale dynamics of the North Sea. Exemplarily, the Skagerrak region is used to demonstrate that high-resolution drifter observations capture both mesoscale and small-scale current patterns. This unique dataset, covering the entire southeastern North Sea and the Skagerrak, offers further analysis possibilities and can be used for the investigation of various hydrodynamic and environmental issues, e.g., the analysis of submesoscale current dynamics at ocean fronts, the determination of the kinetic eddy energy, and the propagation of pollutants in the North Sea.

中文翻译：

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北海拉格朗日表面漂流者观测：高分辨率潮汐动力学和表面流概述

摘要。提供了 2017 年至 2021 年 17 个部署中覆盖北海中部地区和斯卡格拉克的 85 个拉格朗日表面漂流者轨迹数据集。数据经过质量控制、结构统一，并采用标准 NetCDF 格式（https://doi.org/10.1594/PANGAEA.963166，Meyerjürgens 等人，2023a）。使用此处详细介绍的适当方法，根据漂移器位置数据计算表面电流。基于斯卡格拉克的漂流器部署，证明了可以通过计算平均水流速度将拉格朗日测量结果转换为欧拉表示。分别分析了北海南部和北部地区的潮汐能谱，并计算潮汐椭圆以确定潮汐对海表流的影响。北海浅层陆架和较深区域之间的显着差异是显而易见的。虽然浅海近岸区域主要受潮汐流支配，但斯卡格拉克等较深区域则记录了由高密度梯度驱动的高平均剩余环流。使用欧拉方法和遥感方法的测量在时间和空间覆盖范围上受到限制，特别是在捕获精细尺度动态方面。因此，拉格朗日测量在很大程度上为北海复杂的亚尺度动力学提供了新的见解。例如，斯卡格拉克地区用于证明高分辨率漂流观测可以捕获中尺度和小尺度的电流模式。这个独特的数据集覆盖了整个北海东南部和斯卡格拉克海峡，提供了进一步分析的可能性，可用于研究各种水动力和环境问题，例如，分析海洋前缘的亚中尺度海流动力学、确定动涡流能源和北海污染物的传播。