文献类型：期刊文献

英文题名：Formation and transport of fluid mud triggered by typhoon events in front of the subaqueous Changjiang Delta

作者：Tang, Jieping[1,2];Wu, Hao[2];Xing, Fei[3];Zhang, Fan[3,4];Tang, Bixuan[3];Li, Gaocong[1];Wang, Ya Ping[2,3]

机构：[1]Guangdong Ocean Univ, Sch Elect & Informat Engn, Zhanjiang 524088, Peoples R China;[2]Nanjing Univ, Sch Geog & Oceanog Sci, Nanjing 210093, Peoples R China;[3]East China Normal Univ, State Key Lab Estuarine & Coastal Res, Shanghai 200241, Peoples R China;[4]Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai 519082, Peoples R China

年份：2023

卷号：460

外文期刊名：MARINE GEOLOGY

收录：SCI-EXPANDED(收录号：WOS:001009024900001)、、EI(收录号：20231914074334)、Scopus(收录号：2-s2.0-85158863653)、WOS

基金：This study was supported by the Innovation Program of Shanghai Municipal Education Commission (2019-01-07-00-05-E00027) , the Program for Scientific Research Start-up Funds of Guangdong Ocean University (060302112104) , the stable supporting fund of Acoustics Science and Technology Laboratory (JCKYS2021604SSJS008) , the National Natural Science Foundation of China (U2240220, 41625021, 42006151) , the Shanghai Sailing Program (20YF1411300) , and Science and Technology Commission of Shanghai Municipality (18dz2271000) . We thank Changchen Ji, Hui Sheng, Tingfei Lan, and Dezhi Chen for their assistance in the fieldwork and laboratory measurements.

语种：英文

外文关键词：Fluid mud; Gravity flow; Sediment transport; Landform; Typhoon; Changjiang Estuary

外文摘要：Fluid mud supported by waves can move downslope on a gentle slope under gravity to transport massive sediment across the continental shelf and cause significant geomorphological changes. In order to explore the formation and transportation of fluid mud under extreme conditions, we undertook in-situ measurements and observed fluid-mud-related processes triggered by a typhoon, Danas, in the subaqueous Changjiang Delta. Under the action of waves, firstly, the seabed was eroded slowly for similar to 930 min caused by the wave-enhanced bed shear stress; next, rapid erosion occurred when the bed erodibility M-e/rho(B) doubled the value during no waves. The great change in bed erodibility implied that bed liquefaction occurred due to waves. The fluid mud occurred concurrently with the strongest waves and went through five stages with an interval of 0.5-3.5 h between each stage in which waves weakened continuously. In addition, the five fluid mud stages all underwent three identical phases, i.e., formation, stabilization, and decay. In the formation and decay phases, the bottom friction force exceeded the buoyancy gravitational force, and the gradient Richardson number (Ri) was lower than the typical threshold of 0.25, indicating that fluid mud was unstable due to high turbulence energy enhanced by Kelvin-Helmholtz instabilities. During the stabilization phase, the buoyancy gravity force was almost balanced with the drag friction force, and Ri was close to or higher than 0.25, suggesting a laminar fluid mud status. Eventually, the fluid mud disappeared when significant wave height decreased to <1.39 m. Our observation results showed that bed erosion and liquefaction both contributed to the formation of the fluid mud, and the fluid mud played an important role in sediment transportation and bed landforms in subaqueous deltas during extreme events.