台灣海峽陸棚區域潮位修正研究

Abstract

台灣海峽地形屬於典型的大陸棚地形，其水深較淺。此陸棚區域受到地形因素影響，其潮差變化相對於台灣東部太平洋海域更為劇烈，並且於台中外海處，潮差變化達到最大值。台灣海峽陸棚區域因水深較淺且潮差變化較為劇烈，因此在此區域進行水深測量作業時，務必將測深機所蒐集得來之原始水深值扣除潮位高程得到正確之水深值。 台灣所設置之潮位觀測站，其設站位置多以沿海為主，外海區域較缺乏潮位觀測資料。若水深測量施測海域位於距離潮位站較遠之外海處，以往通常是直接使用沿岸潮位站觀測資料進行潮位修正，但使用此種修正方式必須考量到近岸與離岸之間的潮位高程差異。若想降低此差異量大小，可以使用潮位分區修正法代替沿岸潮位站觀測資料修正法。潮位分區修正法將沿岸潮位觀測資料透過潮位改正量及時間改正量調整，推估出其他海域的潮位高程值。 本論文使用潮流模式資料、沿岸潮位站觀測資料、單音束測深資料檢視潮位分區修正法的成效。經驗證結果得知，使用潮位分區修正法確實改善沿岸潮位站觀測資料修正法所帶來的沿岸與離岸之潮位高程差異量大小。除此之外，本研究亦歸納出台灣海峽陸棚海域之潮位站歸屬，透過此潮位站歸屬圖，即可得知施測海域使用何處潮位站資料進行潮位修正，能夠使潮位高程差異量降低至最小。

Taiwan Strait is a typical continental shelf topographic terrain, and the water depth is shallow. Because of the factor of topography, the tidal range in this area changes more intense relative to the Pacific Ocean east of Taiwan. The maximum tidal range value is occurred at offshore area of Taichung. Due to the shallow water depth and the tidal range value, it is important to do tide correction on raw sounding data at Taiwan Strait continental shelf area. Most tide gauges in Taiwan had been deployed at the coastline region, thus there is few tide observations at offshore area. Marine surveyors used to do tide correction at offshore survey region with the coastal tide observations correct method. This method will make the difference of tidal height between coastline region and offshore area. In order to make this difference lower, it can use tidal zoning instead of the coastal tide observations correct method. Tidal zoning makes the calculated tide data of offshore area using range corrector and time corrector from the coastal tide observations. This study using numerical model data, coastal tide observations, and single beam echo sounding data to check the effectiveness of tidal zoning correct method. The result shows using tidal zoning will make lower difference. In addition, this study concluded the responsible region of tide stations located on the western coastline of Taiwan. It will make marine surveyors know how to select the appropriate tide station to do tide correction.