Uncertainty Analysis of Underwater Acoustic Propagation and Detection Performance in Littoral Water
Date Issued
2007-11-26T20:55:13Z
Date
2007-11-26T20:55:13Z
Author(s)
Yuan, Mei-Chun
Abstract
The ocean environment is very complicated due to the effect of internal wave activity and the bathymetry changing in littoral water. This research is based on the ocean mooring data in South China Sea during ASIAEX period and utilizes the decomposing EOF to analyze the variation of sea water temperature which is mainly effected by the internal tide and nonlinear internal wave. The EOF method can efficiently detect the activity of internal tide or nonlinear internal wave in water column. Based on the acoustic transmission track of ASIAEX and using the measuring ocean data as the input data for acoustic model can reach a conclusion of the dominance of the acoustic field in the shelf break area as follows. The bathymetry is the major factor of the underwater acoustic energy variation.
The variation of ocean environment in littoral waters is always high than that in deep waters no matter in temporal and spatial scale. The individual parameters of ocean environment, such as seawater temperature, sediment and water depth, have different variation in scale. The variation range of these parameters can be presented by the method of uncertainty. To develop an ocean environment model can analyzes the acoustic field of effecting by ocean parameter. The parameters of most effecting acoustic field are position of source, sound speed of sediment, density and attenuation coefficient of sediment in order.
The wave equation is the basis to describe the property of underwater sound with proper initial condition and boundary condition for acoustic model and to analyze the acoustic energy. The operation of acoustic model relies on precise ocean data as input in order to get correct acoustic field. This research constructs a computing module that can evaluate the sonar performance through coupling ocean environment and acoustic model. At the end of this research, to analyze the characteristic of underwater sound around Taiwan waters based on the ocean database collecting by academic is in order to explore the operation of sonar performance. This result gives a clear picture of sonar detection that can prompt the sonar operating ability.
Subjects
不確定性
ASIAEX
水下聲學
淺海海洋環境
EOF
聲納
uncertainty
underwater acoustic
littoral water
sonar
Type
thesis
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