Suspended sediment modelling in a shelf sea (North Sea (original) (raw)
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Journal of Hydroinformatics, 2014
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Context Seabed, living and non-living resources are exploited increasingly: sand and gravel is needed for beach nourishment and for construction purposes, the accessibility of harbours requires regular dredging and disposal operations, offshore windmills contribute to our future energy supply and pipelines and cables transport gas and electricity to the mainland. The interaction of these activities with seabed and water column nature and processes needs careful consideration. However, present-day impact studies remain often inconclusive because of: the lack of a 'nondisturbed' reference situation, the interference of both naturally and anthropogenically-induced changes and the role of climate change on seabed processes. Moreover, the range of human activities may result in cumulative effects affecting the magnitude and extent of the impact on the seabed. A more sustainable ecosystem-based approach to management is needed, based on an overall marine environmental status and its possible degradation. Setting-up environmental targets and well-balanced monitoring programs have become timely. These will help in ensuring a sustainable use of our marine environment. Objectives The Belgian part of the North Sea (BPNS) has been targeted to investigate the marine ecosystem over the past 100 years. Main objectives include: (1) Increase in knowledge on natural variability of sediment processes; (2) Establish historic baselines, to set environmental targets; (3) Quantification of ecosystem changes, on the medium-to long-term; (4) Demonstration of human impact, with case studies relating seabed and water column changes to both naturally-and anthropogenically-induced sediment dynamics; (5) Assessing climate change scenarios and their effect on seabed processes; and (6) Recommendations of more sustainable exploitation strategies of non-living seabed resources. Conclusions The BPNS is a typical sandbank-swale environment, though the coastal zone comprises of large mud fields, associated with a turbidity maximum. The complexity of processes involved is high and required both small-and large-scale investigations. A combined suite of tools was used, comprising in situ measurements, seabed mapping and modelling. Natural variability of sediment processes Data from quasi-continuous multi-sensor tripod measurements increased significantly our knowledge on the nature and dynamics of suspended particulate matter (SPM).
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Modeling Near-Surface Suspended Sediment Concentration in the English Channel
Journal of Marine Science and Engineering, 2015
The present study investigates the performances of the three-dimensional multicomponent hydro-sedimentary model ROMS (Regional Ocean Modeling System) to predict near-surface suspended sediment concentrations (SSC) in the English Channel (western Europe). Predictions are assessed against satellite-retrieved observations from raw MODIS and MERIS images for the year 2008 characterized by the highest availability of cloud-free data. Focus is put on improvements obtained with: (1) SSC inputs at the open boundaries; and (2) simple parameterizations of the settling velocity and the critical shear stress. Sensitivity studies confirm the importance of the advection of fine-grained suspended sediments in the central waters of the English Channel exhibiting benefits of refined SSC estimations along the sea boundaries. Improvements obtained with modified formulations of the settling velocity and the critical shear stress finally suggest possible seasonal influences of biological activity and thermal stratification on near-surface SSC.
2016
Abstract: The present study investigates the performances of the three-dimensional multicomponent hydro-sedimentary model ROMS (Regional Ocean Modeling System) to predict near-surface suspended sediment concentrations (SSC) in the English Channel (western Europe). Predictions are assessed against satellite-retrieved observations from raw MODIS and MERIS images for the year 2008 characterized by the highest availability of cloud-free data. Focus is put on improvements obtained with: (1) SSC inputs at the open boundaries; and (2) simple parameterizations of the settling velocity and the critical shear stress. Sensitivity studies confirm the importance of the advection of fine-grained suspended sediments in the central waters of the English Channel exhibiting benefits of refined SSC estimations along the sea boundaries. Improvements obtained with modified formulations of the settling velocity and the critical shear stress finally suggest possible seasonal influences of biological activ...