[1] Being one of the most outstanding hydrodynamic processes at ocean margins, upwelling is not only a key factor controlling bioproduction but also acts as a driving mechanism for sediment transport. In order to quantify its capability to erode and transport sedimentary particles without being masked by other oceanographic processes, we present a numerical model only forced by surface wind drag. Thereby, transport of particles is not only controlled by upwelling circulation, but also by their physical properties as well as time and location of release into the water column. The study combines a hydrodynamic finite difference model and Lagrangian particle tracing technique. Model geometry mimics a two-dimensional profile from the passive margin offshore Walvis Bay, Namibia. Model runs describe a 5-day wind-forcing event and a subsequent 20-day period of relaxation. As our work is also motivated by paleoceanographic questions, a lowered sea level geometry is used simulating Last Glacial Maximum (LGM) conditions. Results suggest the establishment of a long-lasting circulation comprising an offshore-directed surface layer and an onshore-directed bottom current. Shelf currents are vigorous but short-lasting, allowing transport of particles up to sand size. In contrast, transport at the upper slope is more persistent but restricted to smaller grain sizes. Sea level changes cause a shift of upwelling front in cross-shelf direction and of sedimentary deposition centers along the slope. Transport paths of surface source tracers show systematic variations, which can be evaluated in terms of grain-size fractionation as well as temporal and spatial clusters.
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