Abstract Rip currents in the southern Baltic Sea coastal zone are one of the most incompletely known and least explored hydrodynamic phenomena. As they are rare, discussion on their nature, their contribution to the complex pattern of nearshore currents, and their effect on, inter alia, the seafloor transformations is still on-going. Observations made during this study confirmed the occurrence of rip currents at the southern Baltic Sea shore. During field surveys in 2011–2013, Lagrangian measurements taken using novel GPS-tracked drifters revealed several flow events with features characteristic of rip currents. At the same time, numerical calculations produced a three-dimensional wave-current field in the surf zone. Both the measurements and numerical modelling made it possible to follow the rip current dynamics in the area of study and to compare the rip currents observed with those known from other reflective coasts. In addition, wave action-related and bathymetric conditions conducive to the rip current emergence were identified, and the relationship between the rip current velocity, wave regime and local seafloor morphology was explored. The results confirm the theory of rip currents at dissipative shores emerging at the prevalence of fairly flat long waves. Such conditions are typical at swells, i.e., during storm abatement.

中文翻译：

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波罗的海南部多杆近岸区的撕裂流

摘要 波罗的海南部沿海地区的离岸流是最不完全了解和探索最少的水动力现象之一。由于它们很少见，关于它们的性质、它们对近岸海流复杂模式的贡献以及它们对海底转变等的影响的讨论仍在进行中。在这项研究中进行的观察证实了波罗的海南部海岸存在离岸流。在 2011-2013 年的实地调查中，使用新型 GPS 跟踪漂流器进行的拉格朗日测量揭示了几个具有裂口流特征的流动事件。同时，数值计算在冲浪区产生了三维波流场。测量和数值模拟都使得跟踪研究领域的裂口流动力学以及将观察到的裂口流与其他反射海岸已知的裂口流进行比较成为可能。此外，确定了有利于离岸流出现的波浪作用相关和测深条件，并探讨了离岸流速度、波浪形态和当地海底形态之间的关系。结果证实了在相当平坦的长波盛行时出现的耗散海岸的离岸流理论。这种情况在涌浪时是典型的，即在风暴减弱期间。并探讨了离岸流速度、波浪形态与当地海底形态之间的关系。结果证实了在相当平坦的长波盛行时出现的耗散海岸的离岸流理论。这种情况在涌浪时是典型的，即在风暴减弱期间。并探讨了离岸流速度、波浪形态与当地海底形态之间的关系。结果证实了在相当平坦的长波盛行时出现的耗散海岸的离岸流理论。这种情况在涌浪时是典型的，即在风暴减弱期间。