The main minerals in suspension are philittic clays, which give the SPM the tendency to flocculate. The Aulne river estuary is a shallow, macrotidal tributary of the Bay of Brest. On 21 January 2015, an experiment was conducted from a small vessel under the Térénez bridge in the Aulne estuary, northwestern France (Fig. Here, a new fast and accessible protocol for SPM quantification using an MBES is proposed through an original field experiment.įigure 1: Aulne estuary location, France. Both issues can be overcome to achieve SPM quantification using MBES water column data, through the one-time calibration of the MBES antenna with a standard target and provided that measurements of multifrequency acoustic profiles are regularly repeated over time during the MBES survey. Interpreting MBES measurements in terms of SPM remains intricate, however, due to complex MBES antenna designs, which require absolute calibration, and its sole emitting frequency (or at least limited frequency range in the case of multifrequency systems). ![]() As such, MBES provides an opportunity to acquire SPM data in the water column with a better spatial representativeness than other acoustic systems such as ABS and ADCP. The multibeam echosounder (MBES) is however widely-used for bathymetry applications and can provide two-dimensional water column backscatter images over its swath. Systems typically used in SPM studies are the acoustic Doppler current profiler (ADCP) and acoustic backscatter profiling sensors (ABS). Significant efforts have been devoted in recent decades to SPM monitoring at various temporal and spatial scales in coastal oceans and rivers. ![]() The distribution and transport of suspended particulate matter (SPM) can impact the environment, from marine habitats and water quality to seabed morphology. The method is fast, easily applicable, and offers great promise for retrieving large-scale information about suspended particulate matter in the water column in coastal areas. It relies on the joint use of a hull-mounted multibeam sonar calibrated on site, and an acoustic backscatter profiler working at multiple frequencies. ![]() A novel methodology to monitor particles in the water column over a wide spatial coverage is described here. Measuring suspended particulate matter in the water column is still a big challenge when it comes to covering wide areas in the sea or rivers.
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