近十年灰鳖洋动力地貌演变特征研究

Study on dynamics geomorphology evolution of Huibieyang zone in recent ten years

灰鳖洋位于杭州湾口南部,受长江口入海泥沙、杭州湾和金塘水道水动力长周期变化的共同影响,灰鳖洋一直处于"海床基本稳定,东部微冲西部微淤"的动力地貌演变特性,但本世纪以来,这一特性发生了重大变化。应用2002年至2011年灰鳖洋水下地形和水文测验资料,辅以数学模型手段,分析了近10年灰鳖洋动力地貌演变特征,并从多方面探究了演变特性转变的原因,研究表明:灰鳖洋呈近岸缓慢淤积、离岸快速冲刷、累积性冲淤、近岸潮动力明显减弱、中东部潮动力增强的演变特点;近10年演变特性的变化是对泥沙环境变化及人类活动的直接响应。

Huibieyang is located in the south of Hangzhou Bay＇s entrance. Owing to the Yangtze river＇s sediment and the influences of Hangzhou Bay and Jintang Channel, the dynamic geomorphology of Huibieyang was always characterized basically stable with slight scouring and silting. However this property has undergone ma- jor changes in this century. The paper analyzes the seabed evolution on Huibieyang zone in recent ten years, and the reason of changes from relative factors based on bathymetrie maps and hydrodynamic numerical model. The result indicated that the seabed evolution on Huibieyang was mainly characterized serious scouring, while the nearshore zone was characterized serious silting-up, and the scouring or silting was the same direction. The tidal power was weaker in west nearshore zone, while the tidal power in middle and east of Huibieyang zone were more powerful. The evolution in Huibieyang is the response of the changes of sediment and human activities.