Remotely sensed images document the occurrence of multiple packets of internal solitary waves (ISWs) in the Rhine River plume at the same time. We use a combination of field observations, and non-hydrostatic and hydrostatic modeling to understand the processes that lead to the generation and retention of multiple ISW packets within the Rhine plume. Previous numerical modeling shows that the tidal plume front is trapped in the mid-field plume for more than one tidal cycle due to tidal straining and recirculation within the plume, resulting in the presence of multiple fronts in the near-and mid-field plume regions. In this work, we show how variations in the strength of these fronts can lead to the release of ISW packets. We conclude that the retention of the fronts in the mid-field region of the plume and modulation in the strength of the fronts can explain the presence of multiple ISW packets. A frontal Froude number analysis shows that fronts generated during the previous ebb tide can release ISWs in addition to the newly released tidal plume front.

中文翻译：

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潮汐河羽流中多个内波包的观测

遥感图像记录了莱茵河羽流中同时出现了多个内部孤立波 (ISW) 包。我们结合使用现场观察以及非静水和静水建模来了解导致在莱茵河羽流中产生和保留多个 ISW 数据包的过程。先前的数值模拟表明，由于潮汐应变和羽流内的再循环，潮汐羽流锋被困在中场羽流中超过一个潮汐周期，导致近场和中场羽流区存在多个锋面. 在这项工作中，我们展示了这些前沿强度的变化如何导致 ISW 数据包的释放。我们得出结论，在羽流的中场区域保留锋面和锋面强度的调制可以解释多个 ISW 包的存在。锋面 Froude 数分析表明，除了新释放的潮汐羽流锋外，前一次退潮期间产生的锋面还可以释放 ISW。