The study is based upon the Vertical Line Array (VLA) of the Asian Seas International Acoustic Experiment (ASIAEX), dated from May 3, 2001 to May 16, 2001, in which the ambient noise was measured and the six frequencies (including 50, 100, 200, 400, 800, 1,200 Hz) were analyzed. The depth dependence of ambient noise levels in shallow water is not significant, and the fluctuations of ambient noise levels can be measured by Fourier analysis. With the similar analysis on static water pressure and temperature variation, the acoustic data has shown obvious in K1 and M2 tidal periods. The frequency dependence of ambient noise was also investigated, the lower frequency components, 50, 100, and 200 Hz, were mainly contributed from distant shipping noise, and the local wind was the dominating factor in higher frequencies such as 400, 800, and 1,200 Hz. This result was further verified by the increased levels at higher frequency due to the typhoon Cimaron during the experiment. Finally, the probability distribution function of ambient noise levels was calculated at each frequency, and was found the lower frequency ambient noise levels were not significantly affected by the typhoon as higher frequency. The threshold frequency of the ambient noise levels affected by the wind wave is about 400 Hz.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0730103-093748 |
| Date | 30 July 2003 |
| Creators | Liu, Chih-Sheng |
| Contributors | Chi-Fang Chen, Ruey-Chang Wei, Shiuh-Kuang Yang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0730103-093748 |
| Rights | unrestricted, Copyright information available at source archive |
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