利用 NTU-RAY 進行聲學反算海流之可行性研究

Abstract

海流是海洋研究重要的一部分，而了解它最直接的方式就是由流速和流向著 手，因此本研究想利用NTU-RAY[1]計算出不同特徵聲線(Eigen Ray)之歷時 (Travel Time)，並透過基因演算法(Genetic Algorithms)來反推聲源至接收器路徑上 之平均流速剖面，在模擬時聲源設在台灣東北海洋觀測系統(MACHO, MArine Cable Hosted Observatory)北邊10 km 處而接收器的點位設在台灣東北海洋觀測 系統之水聽器的位置和聲源西邊10 km 處，透過模擬可反算出平均流速剖面但存 在著0.0019 至0.0515 m/s 的流速誤差和0.3623°至12.5387°的流向誤差。在論文 的最後規劃在台灣東北海洋觀測系統之實驗，以確認此方法在實際海域實行之可 行性。

Current research is one of the important parts in oceanography. Current speed and direction are essential characteristics. This study calculates travel times of different eigen rays using NTU-RAY, and estimates the average current velocity profile from source to receiver with travel time by genetic algorithms. In the simulation, source is located 10 km north of the receiver (hydrophone of Marine Cable Hosted Observatory, MACHO) and one of receiver is the hydrophone in the MACHO system, the other receiver is 10 km west of the source. The average velocity profile is determined through simulation and inversion process, but had 0.0019 - 0.0515 m/s error and 0.3623° - 12.5387° error in direction. Lastly, an experiment utilizing the hydrophone of the MACHO system is proposed for current inversion at the site.