面對全球海岸帶環境問題日益嚴峻的情勢，國際間開展了Future Earth Coast (前身為LOICZ)計畫，桃園藻礁當前面臨的保護與開發的衝突正是該計畫的議題之一。藻礁海域周邊的工業放流水以及海漂垃圾問題尤為嚴重，這些陸源物質在近岸海域的影響範圍由水動力與混合擴散特性決定，本研究之目的為運用Stokes Boundary Layer理論分析其水動力與混合擴散特性，最終提出一個新的更容易應用的海岸帶混合與擴散行為的觀測方法。採用的策略包括理論分析與現場實驗。理論解析方面，本研究將採用原用以解析波浪往復運動時海底底床邊界層內動力特性的Stokes Boundary Layer理論：u(y,t)=U0[cos(Ωt)-e-kycos(Ωt-ky)]，其中k=sqrt(Ω/2ν)，ν為延散係數。本研究將延伸應用於描述海岸帶受半日潮潮流沿海岸往復運動時水體的混合與擴散特性。現場實驗方面，本研究利用自行開發的漂流浮球陣列進行觀測，將不同離岸距離y、不同時間t的觀測流速以理論公式回歸分析得到k，推求海岸帶延散係數ν，討論不同的波浪條件對於理論適用性與參數回歸的影響。此外，本研究將繼續維持海岸監測實驗站運行，持續監測台灣西部海岸長期背景環境參數。研究結果，一方面將可掌握藻礁海域的水體混合與擴散特性，提供實際延散係數作為數值模式設定的依據，以更準確地模擬泥沙、溶解態物質與海漂垃圾的輸送；同時更重要的是，提出一個新的海岸帶混合與擴散行為的解析方法，更易於運用到其他區段海岸帶中。 ;In the face of the increasingly severe environmental problems in the global coastal zone, the Future Earth Coast (formerly LOICZ) project was launched internationally. The current conflict between protection and development in Taoyuan algae reef is one of the topics of the project. The problem of industrial discharge water and marine debris around the algae reef is particularly serious. The influence of these terrestrial materials in coastal waters is determined by hydrodynamic and dispersion characteristics. The purpose of this study is to analyze the hydrodynamic and dispersion characteristics using Stokes Boundary Layer theory, and finally propose a new and easier method to measure the dispersion coefficient in coastal water.The strategies adopted include theoretical analysis and field experiments. In terms of theoretical analysis, this study will use the Stokes Boundary Layer theory which is originally used to analyze the dynamic characteristics of the boundary layer of the seabed bed when the wave reciprocates: u(y,t)=U0[cos(Ωt)-e-kycos(Ωt- ky)], where k = sqrt(Ω/2ν), ν is the dispersion coefficient. It will be extended to describe the mixing and dispersion characteristics of water when the oscillatory tidal current flows along the coast. In the field experiment, the self-developed drifters will be adopted. And the observed flow velocity of different offshore distance (y) and different time (t) will be analyzed by the theoretical formula to obtain (k), and the coast dispersion coefficient (ν) will be derived. The applicability of the Stokes Boundary Layer will be discussed under different wave conditions. In addition, the study will continue to maintain the Coastal Monitoring Experimental Station to get the continuously long-term background environmental data of the western coast of Taiwan.By conducting this project, the dispersion characteristics of the algae reef coastal ocean will be grasped, and the actual dispersion coefficient could be provided to the numerical model to get more accurately simulate of transport of sediment, dissolved matter and marine debris. What is more, we will try to propose a new and easier method for the mixing and dispersion evaluating in coastal zones.
