气候变化领域集成服务门户(CCPortal): Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents

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DOI	10.1029/2019JC015904
	Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents
	Simmons S.M.; Azpiroz-Zabala M.; Cartigny M.J.B.; Clare M.A.; Cooper C.; Parsons D.R.; Pope E.L.; Sumner E.J.; Talling P.J.
发表日期	2020
ISSN	21699275
卷号	125 期号:5
英文摘要	Turbidity currents transport prodigious volumes of sediment to the deep sea. But there are very few direct measurements from oceanic turbidity currents, ensuring they are poorly understood. Recent studies have used acoustic Doppler current profilers (ADCPs) to measure velocity profiles of turbidity currents. However, there were no detailed measurements of sediment concentration, which is a critical parameter because it provides the driving force and debate centers on whether flows are dilute or dense. Here we provide the most detailed measurements yet of sediment concentration in turbidity currents via a new method using dual-frequency acoustic backscatter ADCP data. Backscatter intensity depends on size and concentration of sediment, and we disentangle these effects. This approach is used to document the internal structure of turbidity currents in Congo Canyon. Flow duration is bimodal, and some flows last for 5–10 days. All flows are mainly dilute (<10 g/L), although faster flows contain a short-lived initial period of coarser-grained or higher-concentration flow within a few meters of the bed. The body of these flows tends toward a maximum speed of 0.8–1 m/s, which may indicate an equilibrium in which flow speeds suspend available sediment. Average sediment concentration and flow thickness determine the gravitational driving force, which we then compared to average velocities. This comparison suggests surprisingly low friction values, comparable to or less than those of major rivers. This new approach therefore provides fundamental insights into one of the major sediment transport processes on Earth. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	acoustic inversion; submarine canyon; suspended sediment; turbidity current
语种	英语
来源期刊	Journal of Geophysical Research: Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/186873
作者单位	Energy and Environment Institute, University of Hull, Hull, United Kingdom; Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, Netherlands; Departments of Earth Sciences and Geography, University of Durham, Durham, United Kingdom; National Oceanography Centre, Southampton, United Kingdom; Formerly at Chevron Energy Technology Company, San Ramon, CA, United States; School of Ocean and Earth Sciences, University of Southampton, Southampton, United Kingdom
推荐引用方式 GB/T 7714	Simmons S.M.,Azpiroz-Zabala M.,Cartigny M.J.B.,et al. Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents[J],2020,125(5).
APA	Simmons S.M..,Azpiroz-Zabala M..,Cartigny M.J.B..,Clare M.A..,Cooper C..,...&Talling P.J..(2020).Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents.Journal of Geophysical Research: Oceans,125(5).
MLA	Simmons S.M.,et al."Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents".Journal of Geophysical Research: Oceans 125.5(2020).