同济大学阮威涵团队近日揭示了潮汐产生的非线性内波在深海底边界层输运沉积物。2025年6月26日出版的《地质学》杂志发表了这项成果。

作为一种全球分布的高能海洋运动，由于缺乏直接的现场观测，非线性内波（NLIW）穿透温跃层进入深海底部边界层（BBL）并导致沉积物运输的能力仍然存在争议。为了解决这个问题，研究组在南海北坡2011米水深处部署了一个三脚架系泊系统，该地区以其强烈的NLIW和向深海输入大量陆源沉积物而闻名。 

该观察证实，当到达深坡而不是局限于陆架和上坡时，NLIW开始变浅和破碎，从而引发沉积物再悬浮。源自吕宋海峡的两种不同类型的NLIW对深海BBL表现出不同的影响。A类NLIW的诱导流与背景流部分对齐，放大了BBL流，贡献了总泥沙通量的50.28%，尽管仅占观测时间的1.63%。

相比之下，B型NLIW的诱导流与背景流相反，削弱了BBL流，抑制了总泥沙通量的29.22%。研究组首次建立了NLIW振幅与BBL温度、流速和剪切速度之间显著的线性相关性，这将有助于推进NLIW-BBL相互作用的参数化，并为NLIW在深海沉积物输运中的作用提供关键见解。

附：英文原文

Title: Tides-generated nonlinear internal waves transport sediment in the deep-sea bottom boundary layer

Author: Danni Lyu, Yanwei Zhang, Zhifei Liu, Yulong Zhao, Weihan Ruan

Issue&Volume: 2025-06-26

Abstract: As a globally distributed high-energy oceanic motion, the ability of nonlinear internal waves (NLIWs) to penetrate the thermocline into the deep-sea bottom boundary layer (BBL) and lead to sediment transport remains controversial due to the scarcity of direct in situ observations. To address this issue, we deployed a tripod-mooring system at 2011 m water depth on the northern slope of the South China Sea, an area renowned for its vigorous NLIWs and significant terrigenous sediment input to the deep sea. Our observation confirms that NLIWs begin shoaling and breaking, thereby triggering sediment resuspension, when reaching the deep slope rather than being confined to the shelf and upper slope. Two distinct types of NLIWs originating from the Luzon Strait exhibit different effects on the deep-sea BBL. Type-A NLIWs, whose induced flows partially align with the background flows, amplify BBL flows and contribute 50.28% of the total sediment flux despite accounting for only 1.63% of the observation time. In contrast, type-B NLIWs, whose induced flows oppose the background flows, weaken BBL flows and inhibit 29.22% of the total sediment flux. Notable linear correlations between NLIWs’ amplitude and the BBL temperature, flow velocity, and shear velocity has been established for the first time, which will help to advance the parameterization of NLIW-BBL interactions and provide crucial insights into the role of NLIWs in deep-sea sediment transport.

DOI: 10.1130/G53499.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G53499.1/659221/Tides-generated-nonlinear-internal-waves-transport