Feasibility of Estimated Shipping Noise In Southern Sea of Taiwan by AIS

• Main Authors: Bing-Syun Sie, 謝秉勳
• Other Authors: Ruey-Chang Wei
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/qkczyy

碩士 === 國立中山大學 === 海下科技研究所 === 103 === Ocean ambient noise is a vital parameter in sonar system, Noise can have different characteristics in various ocean region, because most noise source are time and spatial varying. Shipping noise is the major contributor to ambient noise at lower frequencies, moreover, southern sea of Taiwan is on a main shipping lane of west Pacific. Therefore, estimating the shipping noise is important, especially for strategic consideration in this region. In this thesis, spectra and standard deviation were used to analyze the variation of overall low frequency ambient noise in southern sea of Taiwan, then bandwidth of shipping noise analysis was determined. According to the results, the sound level is more variant in low frequencies with certain periodicity. Comparing with hydrological data and statistics, it can be proved the periodicity of level is related to tide. In order to estimate shipping noise, source level of each ship should be obtained. Source level used in this research was approximated by the multiple regression analysis from Automatic Identification System (AIS), Several Hydrophone Recording Unit (SHRU), and Acoustic Module for Sea-surface Noise (AMSN). Although the correlation coefficient between estimated level and in-situ data is not high as a whole month, but some of days fall between 0.3 and 0.6, that indicates the feasibility of this approach. It was also discussed that strumming noise, range limitation of AIS, AIS’s data lost, and tide may affect the estimation accuracy of low frequency shipping noise, which were proved by AIS, ADCP, and SBE, and the more significant factors are strumming noise and tide.