• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.1-9
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• 2021

High-frequency bistatic sea surface scattering channels according to sea state were measured at an experimental site of Geoje bay in April 2020, and compared with predictions based on scattering theory. A linear frequency-modulated signal with a center frequency of 128 kHz and a bandwidth of 32 kHz was used for the acoustic measurements. Sea surface wavenumber spectrum was calculated from surface roughness data measured by a wave buoy, and bistatic scattering cross-section of Small Slope Approximation (SSA) based on the wavenumber spectrum was estimated. In addition, scattering from near-surface bubbles using wind speed measured during experiments was considered. Surface scattering channel intensity impulse responses were simulated using the scattering cross-section and the simulation results were compared and analyzed with the field data.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.421-429
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• 2002

Sea surface backscattering signal measurements were conducted in the shallow waters off the east coast of Korea to study the acoustic wave scattering from the sea surface. The grazing angles of wave range from 20° to 40° with a frequency of 60 kHz. The wind speed and surface roughness of the experiment area were 3 m/os and below 1 m, respectively. The measured acoustic backscattering strengths greatly exceed the composite roughness predictions at low grazing angles. To account for this discrepancy, the scattering strengths due to a near-surface bubble layer were considered. The prediction with bubble contribution was found to be in good agreement with the experimental measurement.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.191-194
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• 2004

본 연구에서는 해양의 기초 생산자인 잘피 (Zostera marina)의 후방산란 특성을 일주기 동안 관측 하였다. 해상 실험은 2004년 2월 $25\~29$일 기간 중 남해 동대만에서 실시 하였다. 그랩(Grab)을 이용하여 해초지의 입도를 분석 하였으며 주파수별 산란 특성을 고려하기 위해서 17, 30, 50, 80, 100, 그리고 120kHz 음원을 해초지에 수직 지향하여 주, 야간 잘피의 후방 산란을 측정하였다. 실험 환경 분석을 위해 파고와 조석 및 잘피의 생체량(biomass)측정을 실시 하였다. 광합성 시 해초지에서 발생되는 산소 공기는 해수에 의해 용존 되거나 산소 가스 형태로 존재하게 된다. 이들 공기 방울에 의해서 형성되는 공기 방울 층은 음 세기의 감쇠를 야기 시킨다. 실험 결과 주, 야간 동안 음의 산란 강도 변화를 확인 하였다.