Estimating aggregation between suspended sediments and frazil ice

Abstract

This paper aims to describe the scavenging process, one of the main processes for incorporating sediments (particles) into sea ice. An experiment with suspended sediment and frazil ice in a homogeneous turbulent flow is presented. At the end sediment where incorporated into the surface grease ice. The ice production was constant, and calculated from the salinity measurements, while the turbulent dissipation rate was calculated from high resolution current measurements. A model for aggregation between suspended sediment and frazil is also presented and used to simulate the experiment. The modelled aggregation process depends primarily on concentrations, on the turbulence levels, and on the (constant) radii of the sediments and ice. Efficiency of the aggregation process is estimated from the model and experimental results, and the `aggregation' factor is found to be α to approximately 0.025. This is consistent with theoretical estimates, qualitative observations from laboratory experiments, and field data. Sensitivity analyses suggest that the results does not depend greatly on uncertainty of model parameters.