Application of the two-ADCP technique in estuaries to characterize the suspended particulate matter transport

THOMAS, LUIS; MARINO, BEATRIZ; SZUPIANY, RICARDO NICOLÁS

Rio de Janeiro

Simposio; 3rd Acoustics in Underwater Geosciences Symposium (RIO Acoustics 2017); 2017

Acoustic methods have been proved as powerful tools formeasuring the concentration and size of suspended particulate matter (SPM) inaquatic environments predominantly composed of non-cohesive sandy sediments andwith the predominance of steady flows. However, if flocculation occurs andflows are unsteady, interpretation of the acoustic observations is harder. Toprovide a solution to the complex characterization of the suspended particlesin estuarine systems, in this study two acoustic Doppler current profilers(ADCP), working at different frequencies, are simultaneously employed to obtainthe concentration and size distributions of SPM throughout selected transversalsections of a stratified estuary under quiet meteorological conditions and withlow river discharge. The intensity of the ADCPs backscatter signal is calibratedwith LISST-25X measurements. The information obtained in-situ with hightemporal and spatial resolutions is combined with aspects of the estuarinecirculation to give a global description of the dynamical behaviour of SPM.