水深測量之潮位修正方法

Tide Correction methods for Bathymetry Survey

臺灣周邊海域受到潮汐影響，海平面會有周期性高低起伏的現象，在以海平面為參考之測深作業中，由於水深測量的船體是在浮動海平面上測量海床地形，即使是在相同「位置」，於不同「時間」所測量到的海平面深度也會有不同的情形，所以需要將浮動的海平面深度，藉由隨「時間」紀錄的潮位資料，改算至固定的基準面深度，此處理程序稱為「潮位修正」。藉由潮位模式分析，劃分成不同的等潮區，以協助了解測區與潮位站之間的差異，並做為選用潮位修正方法之參考依據。潮位修正可以就是否使用觀測潮位資料，分為兩大類：同步驗潮、非同步驗潮，本文將簡要說明各方法之處理步驟、適用情況與特徵。以橢球面為參考之測深作業中，衛星定位技術的橢球高成果還需要透過垂直基準轉換模型，才能跟不同基準的資料進行整合或差異分析。

"In the waters surrounding Taiwan, the sea level rises and falls periodically due to tides. The bathymetric survey uses vessels to measure the depth of underwater terrain relative to sea level. Even at the same location, the depth measured at different times will not be the same. Therefore, it is necessary to use a tide table to convert the depth over time into a sounding based on a vertical datum. It is called tide correction. Through tide model analysis, it could be divided into number of tide zones to help understand the difference between the survey area and the tide gauge station, as a basis for selecting tide correction methods. According to the needs of observed tide table, tide correction methods are divided into two classes: simultaneous tidal observations and non-simultaneous tidal observations. This article will briefly explain the steps of tide correction, applicable situations and characteristics of each method. The ellipsoid height result of GNSS technology also needs to perform with a vertical datum transformation model in order to integrate or difference analyze with the data of different datum. "