钱塘江河口潮波变化过程

Deformation process of tidal waves in Qiantang Estuary

20 0 0年 9月 ,组织实施了钱塘江河口潮涌同步观测 ,获得潮波变形过程的完整资料。潮波穿过杭州湾 ,潮差大幅增加 ,自湾顶澉浦开始 ,河床溯源抬升 ,在浅水效应影响下 ,潮波变形加剧 ,进而形成涌潮。形成以后 ,因涌潮后潮波仍处涨潮状态 ,指向上游的特征线聚集 ,涌潮高度与当地潮差的比值继续增大。涌潮逐渐成为整个涨潮波面。随后 ,因涌潮后潮波已进入落潮阶段 ,特征线分散 ,涌潮渐弱 ,潮位曲线出现双峰 ,且延伸相当距离。

The tidal bore was synchronously surveyed on the Qiantang Estuary in September 2000, and the systematic data of the process of tidal wave deformation were obtained. The following conclusions were drawn. When the tidal wave goes through the Hangzhou Bay, the tidal amplitude increases rapidly. since river bed rises up upstream from the bay apex, Ganpu, the tidal wave deforms seriously because of shoaling effect when it propagates upstream, and then bore occure. The back of bore is still in the state of flood, the characteristic lines converge towards upstream, therefore the ratio of bore height to tidal range increases continuously until the bore becomes the entire wave front of the flooding phase and the ebbing phase follows immediately. Afterwards, the characteristic lines diverge, and the bore weakens. When the wave travels upstream further, two crests occur in the profile of tidal hydrograph, and this phenomenon keeps for a long distance.