Tidally induced turbulence and suspended sediment

Abstract

Nearly continuous data collected using novel methods are utilized to advance the understanding of turbulence and suspended particulate matter (SPM) dynamics under strong tidal flow conditions. Key instrumentation includes a single acoustic current profiler that provides nearly continuous, concurrent turbulence and SPM information with respect to depth near the seafloor and within the water column. Observations show a lag of about 1 hour in turbulence production between the bottom and 12 meters above the bottom (mab), and of about 1.5 hours for SPM. Estimates of eddy viscosity show values ranging between 10-3 and 10 -2 m2 s-1, with an almost constant mean value of 3.5 × 10-3 m2 s -1 within the bottom 7 meters. The present observations and a previously reported theory show good agreement in both amplitude and phase for SPM and turbulence, when values of eddy viscosity ranging between 3.5 × 10-3 (mean) and 10-2 (maximum) are used. Our data set is valuable for evaluating, developing, and improving turbulence and SPM numerical models. Copyright 2004 by the American Geophysical Union.