江苏中部沿海潮滩对台风暴潮的响应

通过近年来对江苏沿海有影响的台风暴潮作用前后的滩面高程观测,结合台风浪资料分析,探究了江苏中部沿海潮滩对风暴潮的响应过程。结果显示:潮滩剖面在风暴潮期间呈现"低滩侵蚀、沿岸输运、高滩稳定",明显区别于沙质海岸在台风浪作用下"高滩侵蚀、离岸输运、低滩淤积"的演变特征。应用Delft3D平面二维水沙动力数学模型,模拟了正常天气和台风浪情况下的滩面演变,从动力学角度解释了潮滩间不同区域演变特征差异的原因,论证了台风浪对地貌演变的短历时"插曲式"作用,阐明了涨潮优势流是风暴侵蚀后泥沙沿岸向输运的主控因子。

Evolution of tidal flat in response to storm surges:a case study from the central Jiangsu Coast

The response of tidal flats to storm surges is an important scientific problem in the evolution of tidal flats under climate change. To investigate the evolution of silt-muddy tidal flats in response to storm surges along the Jiangsu coast,the measured surface elevation of tidal flats pre-and post-storms and associated hydrological data were analyzed. The evolution of intertidal flats induced by storm surges is characterized by erosion in the upper intertidal flats while accretion in the lower flats. This is distinct from the evolution of sandy coasts which show erosion in the upper zones and accretion in the lower zones led by offshore sediment transport. A two-dimensional numerical model (Delft3D) is established considering tidal currents and sediment transport to simulate the bed evolution under calm and storm conditions,respectively. The hydrodynamic mechanism is explained for the regional characteristics of tidal flats,which shows an episodic effect on morphology after storm waves. The flood-dominated tidal current plays a key role on the long-shore sediment transport.