Measurement of low-frequency underwater noise by a self-recording hydrophone
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Measurement of low-frequency underwater noise by a self-recording hydrophone
Bong-Chae Kim, Hongsang Cho, Byoung-Nam Kim,Chang-Woong Shin, Donggoog Kim, and Bok Kyung Choi
Marine Environment Research DepartmentKorea Ocean Research & Development Institute
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Objectives of this study
To test a newly developed self-recording hydrophone to measure low-frequency underwater noise in the sea
To acquire low-frequency ocean noise data at a site in the South Sea of Korea
To investigate correlation between noise levels and environment variables
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Block diagram and specifications ofself-recording hydrophone
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Receiving frequency characteristics ofself-recording hydrophone
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Self-recording hydrophone
B&K 8103 hydrophone
SD memory
Battery
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Measurement site
KOREA
JAPAN
CHINA
Yellow Sea
East Sea
Korea Strait●
siteSouth Sea
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Instruments installation for noise measurement
Hydrophone(20 m)
10 m10 m
10 mR/V Eardo
Sea bed
52 m Hydrophone(40 m)
ADCP
5 m
RadarAnemometer
Self-recording hydrophone
Sea surface
CTD
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Recording and spectrum analysis systemby conventional cabled hydrophone
Instrumentation cassette recorder
(Sony PC208Ax)
Oscilloscope
(LeCroy LT264M)
Measuring amplifier
(B&K 2636)
Hydrophone
(B& K 8106)
Recording
Personal computer
A/D converter
(NI PCI-6034E, 16bit)
Spectrum analysis
(DADiSP 2002)
Spectrum analysis
Instrumentation cassette recorder
(Sony PC208Ax)
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Environment variables
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Averaged noise spectrum level
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Mean and standard deviation ofnoise spectrum level
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Correlation between wind speed and noise level (20 m depth)
Correlation coefficient = 0.0323 Correlation coefficient = -0.1266
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Correlation between wind speed and noise level (40 m depth)
Correlation coefficient = 0.0286 Correlation coefficient = -0.2638
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Correlation between wind speed and noise level (52 m depth)
Correlation coefficient = 0.1435 Correlation coefficient = 0.0037
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Correlation between current velocity and noise level (20 m depth)
Correlation coefficient = 0.6555 Correlation coefficient = -0.1668
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Correlation between current velocity and noise level (40 m depth)
Correlation coefficient = 0.6303 Correlation coefficient = -0.4576
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Correlation between current velocity and noise level (52 m depth)
Correlation coefficient = -0.3027 Correlation coefficient = -0.0248
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Summary
A self-recording hydrophone was newly developed to use for measurement of low-frequency ocean noise.
Low-frequency noise at a site of the South Sea of Korea was measured by using the self-recording hydrophone and conventional cabled hydrophones.
The self-recording hydrophone is superior to the conventional cabled hydrophone to measure low-frequency underwater noise when in particular water flow is strong.
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Thank you!