Author(s): Massimo Guerrero; Slaven Conevski; Nils Ruther; Vittorio Di Federico

Linked Author(s): Massimo Guerrero, Nils Rüther, Vittorio Di Federico

Keywords: Coustic Doppler current profiler; Signal modulation; Profiling resolution; Turbulence; Suspended sediment concentration

Abstract: The acoustic Doppler current profiler, ADCP, is applied worldwide to characterize the water velocity field in relevant environments (e. g., lake, river channel, estuarian, costal shelf, ocean). This is based on the detection of the Doppler frequency shift from the backscattering strength (BS) of particles transported in the water flow. At the same time the BS is applied to solve the inverse problem which yields the suspended sediment concentration, SSC. Active transducers emit modulated pulses to enhance the Doppler content. Incoherent and coherent techniques result in different bandwidth of the emitted signal which apply at a number of scales and resolutions of velocity profiling. In case of turbulent flow, velocity oscillations within the bandwidth of received signal show an inverse correlation to BS which bore out a possible bias on SSC assessment. Within this contribute a preliminary assessment is proposed which elucidates the scale of overlapping between turbulence fluctuations and sound waves as modulated by the ADCP and the resulting bias on SSC.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0710-cd

Year: 2023