Comparing suspended sediment concentrations derived from a model and collected in a tidally dominated area

Measuring suspended sediment concentration (SSC) in field is still a challenging procedure for oceanographers. Therefore the models which are capable to produce accurate hydrodynamics of a site are relatively inaccurate to simulate sediment dynamic. This investigation is a survey to verify the deficiencies incorporate both model results and field data in a tidal dominated area in regards with SSC data. A flow model from Delf3d in which it’s hydrodynamic was validated for a channel located in the southeaster part of the North Sea, has been used to simulate the sediment dynamic of the field. The investigation was carried out over two cross sections in the channel. The profile of velocity and SSC derived from the model at each cross section were compared with those from the field. Unlike velocities, SSC derived from the model was not in good agreement with those from the field. The ratio of observed (field data) to predicted (model results) SSC along the depth were prepared to find out the depth at which the dissimilarity between the model results and the field data is at most. The dissimilarity in the shallow water area was more evidence. It was suggested to be due to the uncertainty in the measuring device in shallow waters. The ratio of predicted to observed SSC were also plotted against velocity derived from the model. The results showed that the highest dissimilarity was accrued during low velocities, which was suggested to be due to constant settling velocity consideration in the model simulation.

کلیدواژه ها:

tide ، model ، sediment ، concentration ، transmissometer ،