Evaluation of suspended sediment in a fetch limited beach using optical backscatter sensors: particle size effects

Abstract

This study is addressed to the evaluation of the suspended sediment concentration in a fetch limited beach (Alfeite Beach) using optical backscatter sensors (OBS) appraising, simultaneously, sensor response to the physical characteristics of suspended particles. In order to achieve these objectives two OBS sensors, deployed at the intertidal zone of Alfeite Beach, measured sediment concentration during a tidal cycle. Sensor output was calibrated with local bottom and suspended sediments (collected with Niskin bottles). Results show that concentration of suspended sediments is highly dependent on particle size and put in evidence the importance of sensor calibration using real suspended sediments