淡水河河口環流特性之研究

淡水河系為臺灣最長之感潮河川，其感潮河段包括三大支流：大漢溪、新店溪和基隆河。感潮河川是河流注入海洋的過渡水域，此過渡水域連接河川與海洋這兩大不同性質的水系，感潮河川之水理特性較一般河川複雜。影響淡水河河口水理之因素包括淡水流、潮流、密度流、地形流及氣象流等，交互作用，錯綜複雜。淡水河因無長時間之連續水流及鹽分之觀測資料，無法判斷河口環流現象之強弱狀況，本文發展一淡水河系之垂直二維數值模式，模式經過實測資料驗證後，可用以模擬河口環流狀況，另以簡化之河口動力方程式所求得之理論解析解與數值模式計算結果相互比較，並應用數值模式計算河口環流水理及鹽分參數以做為淡水河河口分類。

關鍵字

感潮河川；河口環流；理論解析解；數值模式

並列摘要

The Tanshui River is the largest tidal river in Taiwan. It consists of three major tributaries: the Tahan Stream, Hsintien Stream and Keelung River. The downstream reaches of all three tributaries are tidal. The estuary, together with the tidal freshwater rivers upstream of it, is the pathway for exchange of water and material between its drainage basin and the coastal ocean. The hydrodynamics in tidal river are more complicated than fluvial streams. In Tanshui River, since there is no sequent long-term velocity and salinity observed data to determine directly whether two-layer estuarine circulation exists or not. A vertical two-dimensional estuarine hydrodynamic and salinity model was developed to simulate the hydrodynamic characteristics. The numerical model was calibrated against observed surface elevation, current velocity and salinity distributions and to investigate the factors controlling estuarine circulation. Then the estuarine circulation was investigated with theoretical analysis and numerical simulation. The information derived from theoretical analyses of prototype data are used to compare and verify the results of model simulations. The vertical velocity and salinity distributions from simulation results are used for the basic parameters to classify the types of the Tanshui estuary.

並列關鍵字

Tidal river ； Estuarine circulation ； Theoretical solution ； Numerical model

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