海洋現象中，潮汐是一種相當規律的海面升降現象，和人類的活動息息相關。當潮波傳遞至近岸淺水區域，由於非線性作用使得潮波的波形產生變形，此時便需要利用倍分潮與複合分潮等淺水分潮項來描述這種變形的潮波波形。

潮位變化受淺水分潮項影響顯著的地區，以西北歐的陸棚區為例，此區的M4、MS4分潮振幅最大分別可達到0.25及0.21公尺，較同地區其他大部分的全日潮振幅來得大，在潮位的預測上，便不能忽略這些淺水分潮項。本文利用Princeton Ocean Model (POM)模式，針對台灣海峽淺水區域的高頻淺水分潮項進行推算，並將模式推算結果與台灣西海岸潮位站之實測資料進行比對，進一步探討淺水分潮在台灣海峽的分佈特性。

由模式的推算結果發現，台灣海峽西南方的淺水地形--台灣灘，會對1/3、1/4、1/6日週潮淺水分潮的振幅造成明顯的影響；1/4及1/6日週潮振幅的空間分佈，在台灣海峽內則會有類似於駐波的共振現象發生，從理論與實測資料的分析，均可證實這樣的現象；模式計算的1/5日週潮的振幅值是本文分析各週期淺水分潮中最小的，其振幅的空間分佈，在淡水至新竹一帶最大，將軍、高雄以南振幅最小，此空間分佈與台灣西海岸實測潮位資料比對，發現具有一致的趨勢。此外，由模式的推算結果亦發現當潮波從深水區傳遞至台灣東岸，在經過大陸棚斜坡地形之後進入淺水區，各週期淺水分潮在水深約120米處開始有明顯的振幅變化。

Among all the phenomena in the ocean, tide is the one with regular eustatic movement, which is closely linked to human activities. When tidal waves propagate towards the nearshore shallow water areas, the waveform deforms because of nonlinear interactions. The shallow water tidal constitutes, including overtides and compound tides are thus necessarily introduced in order to describe the deformed tidal waveform.

Considering the northwest European continental shelf, tidal elevations are significantly affected by shallow water effects. The maximum amplitudes of quarter-diurnal tides M4 and MS4 can reach up to 0.25m and 0.21m high, respectively. These quantities are larger than those of most diurnal tides there. It could be seen that the shallow water tidal constituents ought to be taken into consideration for tidal elevation prediction. In present study, Princeton Ocean Model (POM) is adopted to simulate higher harmonics and long period tides in shallow waters in the Taiwan Strait. Computed tidal elevation amplitudes are compared with the observed data of shore-based tidal gauges on the western coast of Taiwan. Furthermore, tidal constituents of higher harmonics and long period tides are used to illustrate the magnitude and spatial variability over the Taiwan Strait.

The results of simulations show that the Taiwan Bank, which locates in the southwest shallow water region of Taiwan Strait, induces significantly the spatial variations of amplitudes of third-diurnal, quarter-diurnal and sixth-diurnal tides. The spatial distribution of amplitudes of quarter-diurnal and sixth-diurnal tides is similar to the resonance of standing waves. This phenomenon can be confirmed by both theoretical derivation and the analyses of observed data. The fifth-diurnal constituent features the smallest amplitude in present study. The maximum amplitude of fifth-diurnal constituent occurs from TamShui to Hsinchu, whereas the minimun amplitude occurs in south of Kaoshiung. The spatial distribution of amplitudes of fifth-diurnal constituent is consistent with field data observed from the tidal gauges on the western coastline of Taiwan. In addition, the result of simulations also demonstrate the facts that the amplitude variations of higher harmonics and long period tides become significant in cases if the water depth is less than 120m. It is the water depth when tidal waves propagate from deep Pacific Ocean towards the continental shelves of the eastern Taiwan.

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