Sequoia manufactures two instruments based on laser diffraction for monitoring sediments entering hydro turbines. These are the LISST-Hydro and LISST-Infinite. These two produce data on sediment concentration sorted into 3 size classes – fine (<75μm),...
The LISST-ABS would reveal rich sediment structure that turbidity misses. For measuring suspended sediments, the use of optical backscatter sensors or other turdibity sensors is widespread. At the same time, it is understood that these sensors respond...
This Note is written for those users who wish to get a deeper understanding of acoustic backscattering and its use in the LISST-ABS. It expands on the very simple page, How LISST-ABS Works. What follows is a description of coherent and incoherent scattering,...
Updated: 4 March 2016. INTRODUCTION: Sequoia’s Acoustic Backscatter Sensor, LISST-ABS is designed to measure suspended sediment concentration at a point. Unlike ADCP’s which may record similar backscatter strength at multiple points (‘ranges’)...
This Note shows how the calibration of the LISST-ABS acoustic backscatter sensor and of optical backscatter sensor (OBS) changes when water contains a broad distribution of particle sizes, and why LISST-ABS is inherently superior. Particle size distributions...