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2015 Vol.34, Issue 1
Analysis of Surface Sound Channel by Low Salinity Water and Its Mid-frequency Acoustic Characteristics in the East China Sea and the Gulf of Guinea

동중국해와 기니만에서 저염분수로 인한 표층음파채널과 중주파수 음향 특성 분석

Hansoo Kim1
,
Juho Kim1
,
Dong-Guk Paeng1*
김 한수1
,
김 주호1
,
팽 동국1*
1Department of Ocean System Engineering, College of Ocean Science, Jeju National University
1제주대학교 해양시스템공학과
*교신저자. *Corresponding Author. 
31 January 2015. pp. 1-11
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Abstract

Salinity affects sound speed in the low salinity environment, in the seas where freshwater from large rivers and flows into the marginal sea area near the Yangtze River and the Niger River. In this paper, SSC (Surface Sound Channel) formed by low salinity water was investigated in the East China Sea and the Gulf of Guinea of rainy season. The data from KODC (Korea Oceanographic Data Center) in the East China Sea and from ARGO (Array for Real-time Geostrophic Oceanography) in the Gulf of Guinea of the tropical area were used for analysis. SSC haline channel was formed 14 times among 32 SSC occurrences when the 90 data from 9 points were analyzed during a decade (2000 ~ 2009) in the East China Sea. In the Gulf of Guinea, haline channel was formed 18 times among 20 SSC occurrences during 3 years (2006 ~ 2009). When the sound speed gradient was analyzed from temperature-salinity gradient diagram, the gradients of both salinity and temperature affect SSC formation in the East China Sea. In contrast, the salinity gradient mostly affects SSC formation due to the least change of temperature in the well-developed mixed layer in the Gulf of Guinea. Their acoustic characteristics show that channel depth is 6.5 m, critical angle is 1.5° and difference of transmission loss between surface and thermocline is 11.5 dB in the East China Sea, while channel depth is 18 ~ 24 m, critical angle is 4.0 ~ 5.4° and difference of transmission loss is 21.5 ~ 27.9 dB in the Gulf of Guinea. These results are expected to be used as a basic understanding of the acoustic transmission changes due to low salinity water at the estuaries and the ocean with heavy precipitation.

Keywords
East China Sea
Gulf of Guinea
Low salinity water
Haline channel
Surface sound channel (SSC)

양쯔강이나 나이저강과 같은 큰 강의 하구를 통해서 많은 담수가 흘러 들어오는 연안에서는 표층염분이 급격히 낮아져서 음속 변화에 영향을 끼친다. 본 논문에서는 우기의 동중국해 해역과 기니만에서 저염분수로 인해 생성되는 표층음파채널(SSC) 현상을 분석하였다. 동중국해는 KODC(Korea Oceanographic Data Center)의 자료를, 적도 부근의 기니만은 ARGO(Array for Real-time Geostrophic Oceanography) 자료를 사용하였다. 수집된 자료를 토대로 표층음파채널 발생동향을 살펴본 결과 동중국해에서는 10년 동안(2000 ~ 2009) 9개 정점에서 측정된 90회 자료 중 표층음파채널은 32회 나타났고 그 중 염분채널은 14회 나타난 반면 기니만에서는 3년 동안(2006 ~ 2009) 20개 정점에서 측정된 20회 자료 중 모든 경우에서 표층음파채널이 발생하였으며 염분채널은 18회 나타났다. 음속구배에 영향을 주는 수온-염분의 기울기를 분석한 결과 동중국해에서는 염분과 수온 변화량 모두 크게 나타나 염분, 수온의 조합에 의한 표층음파채널이 형성되었다. 반면 기니만에서는 혼합층이 잘 발달하여 수온 변화가 적고 염분 변화량이 크게 나타나 주로 염분에 의한 표층음파채널이 형성되었다. 음향 특성 분석 결과 동중국해 정점은 채널두께가 6.5 m, 임계각은 1.5°, 표층과 수온약층에서 전달손실 차는 11.5 dB로 나타났고, 기니만 정점은 채널두께가 18 ~ 24 m, 임계각은 4.0 ~ 5.4°, 전달손실 차이는 21.5 ~ 27.9 dB로 나타났다. 따라서 본 연구는 큰 강의 하구나 강수량이 많은 해역에서 저염분수로 인한 음파전달 변화를 이해하기 위한 기초 자료로 활용될 수 있을 것으로 판단된다.

키워드
동중국해
기니만
저염분수
염분채널
표층음파채널
References
1
1.T. U. Bhaskar, D. Swain, and M. Ravichandran, “Seasonal variability of sonic layer depth in the central arabian sea,” Ocean Science Journal 43, 147-152 (2008).
2
2.T. Delcroix and M. McPhaden, “Interannual sea surface salinity and temperature changes in the western Pacific warm pool during 1992~2000,” J. Geophys. Res. 107, 8002 (2002).
3
3.T. Delcroix and R. Murtugudde, “Sea surface salinity changes In the East China Sea during 1997~2001: influence of the yangtze river,” J. Geophys. Res. 107, 8008 (2002).
4
4.R. C. Beardsley, R. Limeburner, D. Hu, K. Le, G. A. Cannon, and D. J. Pasinski, “Structure of the changjiang river plume in the east China sea during June 1980,” SSCS, 1, 265-284 (1983).
5
5.H. J. Lie, “Structure and eastward extention of the changjiang river plume in the east China sea,” J. Geophys. Res. 108, 3077 (2003).
6
6.K. H. Oh, Y. G. Park, D. I. Lim, H. S. Jung, and J. S. Shim, “Characteristics of temperature and salinity observed at the Ieodo ocean research station” (in Korean), J. Mar. Env. Eng. Soc. Kr. 9 (2006).
7
7.I. O. Kim and H. K. Rho, “A Study on china coastal water appeared in the neighbouring seas of cheju island” (in Korean), Bull. Kr. Fish. Soc. 27, 515-528 (1994).
8
8.N. P. Bulgakov, Yu. V. Artamonov, P. D. Lomakin, and V. N. Cheremin, “Acoustic properties of surface water masses in the tropical Atlantic and their seasonal variability,” Sov. J. Phys. Oceanogr. 3, 2, 141-147 (1992).
9
9.J. H. Kim, T. H. Bok, D. G. Paeng, I. C. Pang, and C. K. Lee, “Acoustic channel formation and sound speed variation by low-salinity water in the western sea of Jeju during summer” (in Korean), J. Acoust. Soc. Kr. 32, 1, 1-13 (2013).
10
10.Korea Oceanographic Data Center, http://kodc.nfrdi.re.kr/
11
11.National Institute of Meteorological Research, http://argo. metri.re.kr/
12
12.H. Medwin, “Speed of sound in water: a simple equation for realistic parameters,” J. Acoust. Soc. Am. 58, 1318-1319 (1975).
13
13.R. J. Urick, Principles of Underwater Sound, 3rd ed. McGrew- Hill, New York ,1983), pp. 78-82.
14
14.M. B. Porter, The BELLHOP manual and user’s guide: PRELIMINARY DRAFT, http://oalib.hlsresearch.com/
15
15.J. S. Youn and T. J. Kim, “Geochemical composition and provenance of surface sediments in the western part of jeju island, korea”(in Korean), JKESS, 29, 328-340 (2008).
16
16.E. L. Hamilton, “Geoacoustic modeling of the sea floor,” J. Acoust. Soc. Am. 68, 1313-1340 (1980).
17
17.J. H. Kim, H. S. Kim, and D. G. Paeng, “Analysis of haline channel formed in the East China Sea and the Atlantic Ocean using the T-S gradient diagram,”J. Kr. Soc. Marine Eng, 38, 2, 208-216 (2014).
18
18.F. N. Fritsch and R. E. Carlson, “Monotone piecewise cubic interpolation,” SIAM J. Numer. Anal. 17, 238-246 (1980).
19
19.L. M. Brekhovskikh and Y. P. Lysanov, Fundamentals of Ocean Acoustics, 3rd ed. (Springer-Verlag, New York, 2003), pp. 1-8.
Information
  • Publisher :The Acoustical Society of Korea
  • Publisher(Ko) :한국음향학회
  • Journal Title :The Journal of the Acoustical Society of Korea
  • Journal Title(Ko) :한국음향학회지
  • Volume : 34
  • No :1
  • Pages :1-11
  • Received Date : 2014-07-13
  • Revised Date : 2014-09-18
  • Accepted Date : 2014-11-04
  • DOI :https://doi.org/10.7776/ASK.2015.34.1.001
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