讲座题目：Effect of shelf morphodynamics on coastline change: modelling free behavior and response to interventions on the shelf
主讲人：Prof. Huib E. de Swart
开始来源：中国足球竞彩比分 时间：2019-07-04 14:00:00
Dr. Huib E. de Swart is professor in Physical Oceanography of Coastal and Shelf Seas, Institute for Marine and Atmospheric Research, Utrecht University. He is also advisory professor at East China Normal University and foreign expert for High-end Project of the State Administration of Foreign Experts Affaires, China. His research interests are tide-topography interactions and related morphological pattern formation(tidal sand banks, sand waves) on coastal shelves; storm-driven currents, waves and shoreface-connected sand ridges on the inner shelf; dynamics of ebb-tidal deltas (in e.g. the Wadden Sea); estuarine dynamics, in particular the feedbacks between water motion, sediment transport and environmental processes: turbidity maxima, phytoplankton pattern formation; waves, currents and dynamics of sandbars in the nearshore zone; circulation and transport processes in the coastal seas (e.g., the North Sea). He is a member of Advisory Committee of Rivers Coast and Estuarine Morphodynamics, a scientific advisor of Flanders Hydraulic Institute, Antwerp, Belgium. He even served as Programme Committee member of Netherlands Centre for Coastal Research, policy/advisory committee member of Netherlands Foundation of Scientific Research, Earth & Life Sciences, and a member of Chairman Board of Studies, Graduate School Natural Sciences. He is also a member of American Geophysical Union, Oceanographic Society, and Scientific Committee, RCEM.
The dynamics of the surf zone strongly depend on the characteristics of incoming sea waves. The latter are determined by the local wind climate, but also by the bathymetry of the inner shelf, e.g. sand ridges cause wave refraction and dissipate part of the wave energy. As the shelf bathymetry evolves on decadal to centennial timescales, due to spatial variations in tide- and wave-induced sand transport, knowledge on how shelf bathymetry affects the large-scale coastal evolution is important. This study investigates the natural hydro- and morphodynamics of a mesotidal coastal system (shelf and surf zone) and their response to interventions on the shelf. For this, the coupled Delft3D-SWAN numerical models employed to solve for tides, waves, sand transport and bed level update on the inner shelf. A one-line model issued to calculate large-scale evolution of the coastline from gradients in the longshore sand transport in the surfzone. This transport is given by the CERC formula, where its input is derived from the wave output of the shelf model. Results will be shown for a domain that crudely mimics the Belgian continental shelf. The natural behavior of the inner shelf is studied by conducting spin-up runs for a period of 1000 years, starting from an initially linear bottom profile in the cross-shore direction. Subsequently, several interventions are created (in particular artificial islands) and the response of the system to these perturbations is studied. It will first be shown that a full process-based morphodynamic model is able to simulate the formation of mature tidal sand ridges on a shelf with a sloping bottom. The variable bathymetry of the shelf has a substantial impact on coastal erosion and accretion patterns. Second, the construction of an island strongly affects the dynamics of the sand ridges and also gives rise to substantial accretion of the coast behind the island and erosion further downstream. Third, shelf dynamics and coastal accretion and erosion rates will be presented for different positions and sizes of the island, as well as for multiple islands.