Novel Acoustic Method Provides First Detailed Measurements of Sediment Concentration Structure Within Submarine Turbidity Currents

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...

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Bibliographic Details
Published in:Journal of geophysical research. Oceans 2020-05, Vol.125 (5), p.n/a
Main Authors: 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.
Format: Article
Language:English
Subjects:
acoustic inversion
Acoustics
Average velocity
Backscatter
Backscattering
Cables
Canyons
Communication cables
Deep sea
Deep sea environments
Dilution
Doppler sonar
Driving ability
Flow duration
Flow velocity
Flowmeters
Friction
Geophysics
Grain size
Gravity
Instruments
Measuring instruments
Ocean currents
Ocean floor
Offshore
Pipelines
Profilers
Profiles
Rivers
Sea currents
Sediment
Sediment concentration
Sediment transport
submarine canyon
Submarine pipelines
suspended sediment
Transport processes
Turbidity
turbidity current
Turbidity currents
Velocity distribution
Velocity profiles
Vertical profiles
Water currents
Water depth
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Summary: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 (
ISSN:2169-9275
2169-9291
DOI:10.1029/2019JC015904