Analysis of LISST-data : report

The LISST-ST is an instrument for measuring in-situ particle size and settling velocity distribution using laser diffraction and transmission. Data from field experiments carried out by RIKZ showed that the standard software of the manufacturer did not suffice to determine settling velocities. New analysis software has been developed by RIKZ, which is not yet able to describe the data fully consistently, however. An important aspect is that the particle densities derived from Stokes' law sometimes show unrealistically high values . Therefore the accuracy of the determined settling velocities is uncertain. The objective of this study is to investigate what are to possible causes for in die inconsistencies in the data. With this knowledge, an advice is to be given on how the accuracy of the LISST-ST data analysis may be improved.