长江口北槽落潮分流比变化原因分析

将长江口南槽和北槽作为一个整体系统,利用实测地形资料和FVCOM数值模型计算流场,研究近10余年北槽落潮分流比变化的水动力原因.通过分析发现,北槽总体呈现断面面积减小和水动力减弱的趋势,而南槽相反,断面面积和断面流速均形成增长的态势,从而在整体上形成了北槽分流比逐渐降低的过程.南北槽断面面积和流速的共同作用导致落潮分流比的变化,定量分析得出断面面积的相对变化比断面流速的相对变化对分流比的影响更大.

Analysis for variation of the ebb flow diversion ratios in the North Passage of the Yangtze River Estuary

Based on seasonal bathymetry observations and high-resolution validated FVCOM model, the North and South Passages in the Yangtze River Estuary are studied as an integrated system to determine the dynamic mechanism controlling their flow diversion ratios in recent ten years. The variations of the sectional areas and averaged velocities are analyzed to reveal the interannual patterns of the diversion ratios between these two Passages. The results show the overall trends of the section area and velocity are both decreasing in the North Passage. However, there is an opposite pattern shown in the South Passage. Therefore, the flow diversion ratio decreases in the North Passage while it increases in the South Passage. Although the variations of section areas and flow strength jointly lead to the changes of diversion ratio, the quantitative linear correlation analysis indicates the change of sections areas has more dominant effect on diversion variation than the change of flow velocity.