Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors

Abstract Optical turbidity and acoustic sensors have been widely used in laboratory experiments and field studies to investigate suspended particulate matter concentration over the last four decades. Both methods face a serious challenge as laboratory and in‐situ calibrations are usually required. F...

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Main Authors: Duc Tran, Matthias Jacquet, Stuart Pearson, Bram VanProoijen, Romaric Verney
Format: Article
Language:English
Published: American Geophysical Union (AGU) 2024-11-01
Series:Earth and Space Science
Subjects:
Online Access:https://doi.org/10.1029/2024EA003694
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author Duc Tran
Matthias Jacquet
Stuart Pearson
Bram VanProoijen
Romaric Verney
author_facet Duc Tran
Matthias Jacquet
Stuart Pearson
Bram VanProoijen
Romaric Verney
author_sort Duc Tran
collection DOAJ
description Abstract Optical turbidity and acoustic sensors have been widely used in laboratory experiments and field studies to investigate suspended particulate matter concentration over the last four decades. Both methods face a serious challenge as laboratory and in‐situ calibrations are usually required. Furthermore, in coastal and estuarine environments, the coexistence of mud and sand often results in multimodal particle size distributions, amplifying erroneous measurements. This paper proposes a new approach of combining a pair of optical turbidity‐acoustic sensors to estimate the total concentration and sediment composition of a mud/sand mixture in an efficient way without an extensive calibration. More specifically, we first carried out a set of 54 bimodal size regime experiments to derive empirical functions of optical‐acoustic signals, concentrations, and mud/sand fractions. The functionalities of these relationships were then tested and validated using more complex multimodal size regime experiments over 30 optical‐acoustic pairs of 5 wavelengths (420, 532, 620, 700, 852 nm) and six frequencies (0.5, 1, 2, 4, 6, 8 MHz). In the range of our data, without prior knowledge of particle size distribution, combinations between optical wavelengths 620–700 nm and acoustic frequencies 4–6 MHz predict mud/sand fraction and total concentration with the variation <10% for the former and <15% for the later. The results also suggest that acoustic‐acoustic signals could be combined to produce meaningful information regarding concentration and mud/sand fraction, while no useful knowledge could be extracted from a combination of optical‐optical pairs. This approach therefore enables the robust estimation of suspended sediment concentration and composition, which is particularly practical in cases where calibration data is insufficient.
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spelling doaj-art-afd216338af640b597fa8f301aa5fef42025-08-20T02:37:39ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842024-11-011111n/an/a10.1029/2024EA003694Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic SensorsDuc Tran0Matthias Jacquet1Stuart Pearson2Bram VanProoijen3Romaric Verney4IFREMER DYNECO/DHYSED Plouzané FranceIFREMER DYNECO/DHYSED Plouzané FranceFaculty of Civil Engineering and Geosciences Delft University of Technology Delft The NetherlandsFaculty of Civil Engineering and Geosciences Delft University of Technology Delft The NetherlandsIFREMER DYNECO/DHYSED Plouzané FranceAbstract Optical turbidity and acoustic sensors have been widely used in laboratory experiments and field studies to investigate suspended particulate matter concentration over the last four decades. Both methods face a serious challenge as laboratory and in‐situ calibrations are usually required. Furthermore, in coastal and estuarine environments, the coexistence of mud and sand often results in multimodal particle size distributions, amplifying erroneous measurements. This paper proposes a new approach of combining a pair of optical turbidity‐acoustic sensors to estimate the total concentration and sediment composition of a mud/sand mixture in an efficient way without an extensive calibration. More specifically, we first carried out a set of 54 bimodal size regime experiments to derive empirical functions of optical‐acoustic signals, concentrations, and mud/sand fractions. The functionalities of these relationships were then tested and validated using more complex multimodal size regime experiments over 30 optical‐acoustic pairs of 5 wavelengths (420, 532, 620, 700, 852 nm) and six frequencies (0.5, 1, 2, 4, 6, 8 MHz). In the range of our data, without prior knowledge of particle size distribution, combinations between optical wavelengths 620–700 nm and acoustic frequencies 4–6 MHz predict mud/sand fraction and total concentration with the variation <10% for the former and <15% for the later. The results also suggest that acoustic‐acoustic signals could be combined to produce meaningful information regarding concentration and mud/sand fraction, while no useful knowledge could be extracted from a combination of optical‐optical pairs. This approach therefore enables the robust estimation of suspended sediment concentration and composition, which is particularly practical in cases where calibration data is insufficient.https://doi.org/10.1029/2024EA003694acousticopticalsandmudSPM concentrationDEXMES
spellingShingle Duc Tran
Matthias Jacquet
Stuart Pearson
Bram VanProoijen
Romaric Verney
Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
Earth and Space Science
acoustic
optical
sand
mud
SPM concentration
DEXMES
title Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
title_full Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
title_fullStr Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
title_full_unstemmed Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
title_short Estimation of Mud and Sand Fractions and Total Concentration From Coupled Optical‐Acoustic Sensors
title_sort estimation of mud and sand fractions and total concentration from coupled optical acoustic sensors
topic acoustic
optical
sand
mud
SPM concentration
DEXMES
url https://doi.org/10.1029/2024EA003694
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AT matthiasjacquet estimationofmudandsandfractionsandtotalconcentrationfromcoupledopticalacousticsensors
AT stuartpearson estimationofmudandsandfractionsandtotalconcentrationfromcoupledopticalacousticsensors
AT bramvanprooijen estimationofmudandsandfractionsandtotalconcentrationfromcoupledopticalacousticsensors
AT romaricverney estimationofmudandsandfractionsandtotalconcentrationfromcoupledopticalacousticsensors