资源环境科技发展态势分析平台

The mechanisms responsible for sediment resuspension and transport by non‐linear internal waves (NLIWs) remain poorly understood largely due to a dearth of detailed field measurements. We present novel observations of the turbulent benthic boundary‐layer (BBL) beneath trains of NLIWs of depression in the ocean. At the 250m deep, low‐gradient (<0.2%) continental shelf site the BBL was near well‐mixed to an average height of about 10 m above the bottom. Above this bottom mixing‐layer, stratification constrained the extent of vertical sediment transport. NLIWs drove sediment transport by a combination of bed‐stress intensification, turbulent transport, and a vertical pumping mechanism associated with the compression and subsequent expansion of the mixing‐layer. There was no evidence that the observed dynamics were associated with a global instability, as proposed in previous studies. The results have implications for cross‐shelf mass transport, and highlight future challenges for measuring and modeling boundary‐layer processes within shelf‐seas.