%0 journal article
%@ 2169-9275
%A Becherer, J., Floeser, G., Umlauf, L., Burchard, H.

%D 2016
%J Journal of Geophysical Research : Oceans
%N 8
%P 6251-6270 
%R doi:10.1002/2016JC011640
%T Estuarine Circulation vs Tidal Pumping: Sediment Transport in a Well-Mixed Tidal Inlet
%U https://doi.org/10.1002/2016JC011640
8 
%X High-resolution water column observations have been carried out in the Wadden Sea to understand suspended particulate mater (SPM) transport in well-mixed tidal channels . These observations include more than 4000 consecutive CTD-, micro-structure shear and turbidity profiles from a free-falling micro-structure probe, as well as velocity data from an ADCP and SPM samples for calibration. A horizontal density gradient was established by a landward temperature gradient built up during an extraordinarily warm and calm spring season. Tidal averaging along σ-layers (relative depth) provides the first direct observations of along-channel estuarine circulation in the Wadden Sea, with net inflow near the bottom and outflow near the surface. Increased westerly (up-estuary) winds during the second part of the campaign weakened and eventually even reversed estuarine circulation and yielded a net barotropic eastward transport. SPM concentrations showed a strong quarter-diurnal signal with maxima near full flood and full ebb and were generally lower during the calm period and increased during the windy period, mainly due to wave-related resuspension over nearby inter-tidal flats. The sediment flux analysis was based on a decomposition of the vertically integrated SPM flux into a barotropic advective component, an estuarine circulation component and a tidal pumping component. As a result, tidal pumping (due to ebb-dominance weakly seaward) dominated the SPM flux during calm conditions, whereas barotropic advection dominated the strong landward SPM flux during the windy period. Along-channel estuarine circulation is found to be of minor importance for the net SPM-transport in such well-mixed systems. This article is protected by copyright. All rights reserved.