本文主要以波浪作用力方程式之通式為架構，利用有限元素法為解析方式，進行近岸波浪數值模式資料同化，以提高模式推算的準確性。本文選擇最佳內插法作為資料同化的方法，以線性疊加方式表示預測值、實測值和起始猜測值的關係，再用最佳權重的觀念決定修正值，增加風浪模式的預測能力。經過均勻風場測試及驗證實際海面波浪場發現，在均勻風場條件下，本文模式能有效修正風場估計的誤差，改善模式的起始推算。對於校正長度 Lmax 之選擇，以6~8倍的格網長度有最佳的權重分配，能使資料同化推算誤差為最小，且當測站數目大於7時，同化分析的修正效果趨於穩定。在推算颱風波浪方面，本文模式在模擬能力較高的東部海域，資料同化能有效提高模式推算之準確度。

　　A revised SWAN model based on the data assimilation technique is developed by using the Finite Element Method (FEM). In the present FEM code the numerical scheme of the original SWAN model is improved to ensure the effectiveness of the computation at every operational stage. To enhance the efficiency of the numerical simulation, the existing experimentally observed data are combined with the first guess values upon linearizing by optimal interpolation. The data assimilation technique reduces the error in the wind field evaluation by using the optimal weighting, in which the correction length is chosen to be 6~8 times that of the gird length. Numerical tests show that the data assimilation analysis tends to be stable as the number of observations is lager than seven. The present model is also successfully applied to the wind wave forecasting at the eastern coast of Taiwan. The results indicate that the present model is applicable to predict typhoon waves efficiently and accurately.

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