|Modeling the sediment concentration profiles at the Amazon Shelf|
Vinzon, S.B.; Paiva, A.M. (2002). Modeling the sediment concentration profiles at the Amazon Shelf, in: Winterwerp, J.C. et al. (Ed.) (2002). Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5: pp. 687-702
In: Winterwerp, J.C.; Kranenburg, C. (Ed.) (2002). Fine sediment dynamics in the marine environment. Proceedings in Marine Science, 5. Elsevier: Amsterdam. ISBN 0-444-51136-9. XV, 713 pp., more
In: Proceedings in Marine Science. Elsevier: Amsterdam. ISSN 1568-2692, more
cohesive sediment dynamics; Amazon shelf
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Experimental data on flow and sediment dynamics on the Amazon Shelf, obtained under AMASSEDS (A Multidisciplinary Amazon Shelf Sediment Study), have been interpreted with the help of a modeling approach in order to examine the vertical structure of flow-sediment interaction. Long-term accumulation mechanisms as well as short-term processes related to the tides are examined in the context of the vertical transport processes. Tidal signatures indicate that sediment dynamics over short time scale is strongly influenced by resuspension events governed by tidal forcing.
A one-dimensional, vertical sediment transport model was developed, assuming a local mass balance in the water column over the tidal time-scale. The model solves the sediment transport equation following the particle tracking method. The sediment settling velocity is considered to be dependent upon the sediment concentration, and the erosion flux function is fitted using in situ near-bed measurements of velocity and sediment concentration. Salt stratification damping of turbulence is also included, and the relationship between shear strength and bed density, required for the calculation of the erosion flux, is derived from laboratory analysis of Amazon sediment samples. The simulated vertical concentration profiles and the near-bed horizontal sediment transported compares well with the observations.