Internal solitary waves in the Shenhu continental shelf slope break zone of the northern South China Sea generate benthic storms  

作　　者：Yonggang JIA Xuezhi FENG Chaoqi ZHU Linsen WANG Xiaolei LIU Cong HU Hongwei WANG 

机构地区：[1]Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering,Ocean University of China,Qingdao 266100,China [2]Laboratory for Marine Geology,Qingdao Marine Science and Technology Center,Qingdao 266237,China [3]Key Laboratory of Submarine Geosciences and Prospecting Techniques,Ministry of Education,Ocean University of China,Qingdao 266100,China

出　　处：《Science China Earth Sciences》2025年第3期928-942,共15页中国科学(地球科学英文版)

基　　金：the National Natural Science Foundation of China for supporting open scientific expeditions in the northern South China Sea (NORC2020-05, NORC2022-05);supported by the National Natural Science Foundation of China (Grant Nos. 41831280, 42207173);the Natural Science Foundation of Shandong Province (Grant No. ZR2022QD002)。

摘　　要：Internal solitary waves can generate intense bottom currents and turbulent mixing over continental slopes, influencing the redistribution of sediments and pollutants, as well as driving changes in marine geomorphology and ecosystems. However,owing to the lack of detailed quantitative measurements of the bottom boundary layer, the mechanisms and impacts of internal solitary waves in resuspending and transporting seafloor sediments remain poorly understood. In this study, we present highresolution in situ observations of hydrodynamics in the upper layer(14–265 m) and the bottom boundary layer(<1 m) in the continental shelf slope break zone. Our results reveal that strongly nonlinear internal solitary waves, which occur at the peak of semidiurnal tidal currents, trigger benthic storms at the seafloor. Unlike previously proposed global instability mechanisms, the suspended sediment concentration caused by these strongly nonlinear internal solitary waves reaches 60 times higher than the background value and exhibits sudden, transient peaks. The bottom shear stress(τ) is an order of magnitude greater than that in laboratory measurements, and the observed fluctuating pressure is approximately 2.3 to 7 times greater than that in previous coastal observations. The sediments stirred by benthic storms are transported vertically to more than 100 m above the seabed,with lateral transport extending tens of kilometres beyond the study area. This process is driven by the dynamic mechanism of“strongly nonlinear internal solitary waves lifting sediments, weakly nonlinear internal solitary waves assisted by internal tides,and contour currents transporting sediments.” The suspended sediment flux induced by internal solitary waves in the South China Sea is on the same order of magnitude as that of global dust storm emissions, 21.9 times the volume of Asian dust storms entering the sea, and approximately 21 times the fluvial sediment flux entering the northern South China Sea. These findings are significant for evaluating sedim

关 键 词：Internal solitary waves Benthic storms Shear stress Suspended sediment flux Fluvial sediment flux 

分 类 号：P73[天文地球—海洋科学]