The Journal of the Acoustical Society of Korea (한국음향학회지)

The Acoustical Society of Korea (한국음향학회)
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Measurements of Mid-frequency Bottom Loss in Shallow Water of the Yellow Sea

서해 천해환경에서의 중주파수 해저면 반사손실 측정

  • 윤영글 (한양대학교 해양융합과학과 해양음향연구실) ;
  • 이찬길 (한양대학교 해양융합과학과 해양음향연구실) ;
  • 최지웅 (한양대학교 해양융합과학과 해양음향연구실) ;
  • 조성호 (한국해양과학기술원 해양방위연구센터) ;
  • 오선택 (한국해양과학기술원 해양방위연구센터) ;
  • 정섬규 (한국해양과학기술원 해양방위연구센터)
  • Received : 2015.04.23
  • Accepted : 2015.08.09
  • Published : 2015.11.30
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Abstract

KIOST-HYU joint acoustics experiment was performed on the western shallow water off the Taean peninsula in the Yellow Sea in May 2013. In this paper, mid-frequency (6~16 kHz) bottom loss data measured in a grazing angle range of $17{\sim}60^{\circ}$ are presented and compared to the predictions obtained using a Rayleigh reflection model. The sediment structure of the experimental site was characterized by multi-layered sediment and the components of the surficial sediment consisted of various types of particles with a mean grain size of $5.9{\phi}$. The model predictions obtained using the mean grain size were not in agreement with the measured bottom loss, and those obtained using the grain size of $4{\phi}$, which was estimated by an inversion process, showed a best fit to the measurements. It would be because the standard deviation of the gain-size distribution of surficial sediment is $4.3{\phi}$, which is much larger than those of other areas around the experimental site. Finally, the model predictions obtained using the geoacoustic parameters estimated from the inversion process for the surficial sediment layer and those corresponding to the mean grain size of $1.3{\phi}$ for lower layer are reasonably agreement with the measured bottom loss data.

한국해양과학기술원과 한양대학교에서 공동으로 진행한 해양음향 실험이 2013년 5월에 경기만 태안반도 서쪽에 위치한 천해에서 실시되었다. 본 논문에서는 측정된 중주파수(6~16 kHz) 해저면 반사손실 결과를 제시하고, 수평입사각 $17{\sim}60^{\circ}$ 범위에서 레일리 반사계수 모델과 비교분석한다. 실험해역 지질은 다중 퇴적층으로 구성되어 있었으며, 표층 퇴적물이 다양한 구성성분(평균 입도 $5.9{\phi}$)으로 이루어져 있는 지역이었다. 분석 결과에 의하면 표층 퇴적물의 평균 입자를 고려한 모델결과는 측정된 반사손실과 다소 차이를 보였으며, 퇴적층의 지음향 정보를 역산한 결과 약 $4{\phi}$ 평균입도에서 측정치와 비교적 잘 일치하는 것으로 나타났다. 이러한 차이의 원인은 표층 퇴적물 입도의 표준 편차가 $4.3{\phi}$로 다른지역에 비해 상당히 컸기 때문일 것으로 추측된다. 상부 퇴적층은 역산 결과로부터 얻어진 지음향 파라미터를 사용하고 하부 퇴적층은 $1.3{\phi}$의 평균입도로부터 예측된 지음향 파라미터를 사용하였을 때, 모델결과는 측정된 반사손실 결과와 전체적으로 일치하는 경향을 나타냈다.

Keywords

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  1. Overview of the KIOST-HYU Joint Experiment for Acoustic Propagation in Shallow Water Geological Environment vol.34, pp.6, 2015, https://doi.org/10.7776/ASK.2015.34.6.411