Acoustic backscatter by suspended cohesive sediments: field observations, Seine Estuary, France
|Author(s)||Sahin Cihan1, Verney Romaric2, Sheremet Alexandru3, Voulgaris George4|
|Affiliation(s)||1 : Yildiz Tech Univ, Dept Civil Engn, TR-34210 Istanbul, Turkey.
2 : PHYSED, DYNECO, Hydrodynam & Sediment Dynam Lab, IFREMER, BP 70, F-29280 Plouzane, France.
3 : Univ Florida, ESSIE, 365 Weil Hall, Gainesville, FL 32611 USA.
4 : Univ South Carolina, Sch Earth Ocean & Environm, Columbia, SC 29208 USA.
|Source||Continental Shelf Research (0278-4343) (Pergamon-elsevier Science Ltd), 2017-02 , Vol. 134 , P. 39-51|
|WOS© Times Cited||29|
|Abstract||Observations of suspended sediment size and concentration, flow and acoustic backscatter intensity collected on the Seine Estuary (France) are used to study the acoustic response in cohesive-sediment dominated environments. Estimates of suspended sediment concentration based on optical backscatter sensors and water samples are used to calibrate the acoustic backscatter intensity. The vertical structure of suspended sediment concentration is then estimated from acoustic backscatter information. To our knowledge, this is the first field application of the recently proposed model of acoustic scattering by flocculating suspensions based on the variation of particle density (floc-scattering model). The estimates of sediment concentration reproduce well the observations under different tidal (neap/spring) conditions, confirming the applicability of the new model in the field when detailed particle size measurements are available. When particle size measurements are not available, using estimated floc sizes based on the turbulence intensities may provide reasonable SSC profiles. During spring tide events (associated with strong currents, small flocs and large concentrations), the performances of the new floc-scattering model and the previous models given for solid particle-scattering are comparable. The floc-scattering model increases the quality of the SSC estimates especially during low-energy conditions characterized with larger flocs.|