The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY (한국해양학회지:바다)

The Korean Society of Oceanography (한국해양학회)
권호 표지
DOI QR코드

DOI QR Code

Application of Objective Mapping to Surface Currents Observed by HF Radar off the Keum River Estuary

금강하구 연안에서 고주파 레이더로 관측된 표층해류에 대한 객관적 유속산출 적용

  • Hwang, Jin-A (Department of Oceanography, BK21 Saemankeum Environmental Research Team, Kunsan National University) ;
  • Lee, Sang-Ho (Department of Oceanography, BK21 Saemankeum Environmental Research Team, Kunsan National University) ;
  • Choi, Byung-Joo (Department of Oceanography, BK21 Saemankeum Environmental Research Team, Kunsan National University) ;
  • Kim, Chang-Soo (Department of Oceanography, BK21 Saemankeum Environmental Research Team, Kunsan National University)
  • 황진아 (군산대학교 해양학과, BK21 새만금환경연구팀) ;
  • 이상호 (군산대학교 해양학과, BK21 새만금환경연구팀) ;
  • 최병주 (군산대학교 해양학과, BK21 새만금환경연구팀) ;
  • 김창수 (군산대학교 해양학과, BK21 새만금환경연구팀)
  • Received : 2010.11.02
  • Accepted : 2010.12.09
  • Published : 2011.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

Surface currents were observed by high-frequency (HF) radars off the Keum River estuary from December 2008 to February 2009. The dataset of observed surface currents had data gaps due to the interference of electromagnetic waves and the deteriorating weather conditions. To fill the data gaps an optimal interpolation procedure was developed. The characteristics of spatial correlation in the surface currents off the Keum River estuary were investigated and the spatial data gaps were filled using the optimal interpolation. Then, the temporal and spatial distribution of the interpolated surface currents and the patterns of interpolation error were examined. The correlation coefficients between the surface currents in the coastal region were higher than 0.7 because tidal currents dominate the surface circulation. The sample data covariance matrix (C), spatially averaged covariance matrix with localization ($C^G_{sm}$) and covariance matrix fitted by an exponential function ($C_{ft}$) were used to interpolate the original dataset. The optimal interpolation filled the data gaps and suppressed the spurious data with spikes in the time series of surface current speed so that the variance of the interpolated time series was smaller than that of the original data. When the spatial data coverage was larger (smaller) than 70% of the region, the interpolation error produced by $C^G_{sm}$ ($C_{ft}$) was smaller compared with that by C.

금강하구 연안역에서 고주파 레이더를 사용하여 2008년 12월부터 2009년 2월까지 표층류를 관측하였는데, 관측된 표층류 자료는 전파의 간섭과 기상 상황에 따라 일시적으로 관측이 이루어지지 않는 구역들이 있었다. 관측된 구역의 자료를 보충하기 위하여 최적보간 과정을 개발하여 적용하였다. 금강하구 연안역에서 표층류의 공간적 상관성의 특성을 조사하고 최적보간법을 이용하여 공간적 결측 구역을 보충하였으며, 보간된 표층류의 시공간적 분포와 산출유속 오차 패턴을 조사하였다. 연구해역 표층 순환에서 조류가 우세하므로 연안역 관측 지점들 사이의 표층해류간 상관계수가 0.7 이상이었다. 원 자료를 보간하기 위해 관측 자료공분산(C), 지역화한 공간평균 공분산($C^G_{sm}$), 지수함수를 이용한 맞춤 평균공분산($C_{ft}$)을 사용하였다. 최적보간이 결측 구간을 채우고, 관측 자료의 시계열 중에서 뾰족하게 튀어나온 비정상적인 자료 부분을 억제하였으며, 그 결과 보간한 유속 자료의 분산은 원 자료의 분산보다 작았다. 공간적 자료획득률이 70% 이상(이하)일 때, $C^G_{sm}$ ($C_{ft}$)를 이용하면 C를 이용한 경우에 비해 보간 오차가 상대적으로 작았다.

Keywords

Acknowledgement

Grant : 해양환경보존을 위한 새만금 연안시스템 연구 프로젝트

Supported by : 군산대학교

References

  1. 김창수, 이상호, 손영태, 권효근, 이광희, 김영배, 정우진, 2006. 새만금 4호 방조제 완성 전후 HF레이더로 관측된 표층 M2조류의 변화. 한국해양학회지(바다), 11: 37-48.
  2. 김창수, 이상호, 손영태, 권효근, 이광희, 최병주, 2008. 새만금 연안역에서 HF radar에 의해 관측된 조하주기 표층해류의 변화. 한국해양학회지 (바다), 13(1) :56-66.
  3. 이상호, 문홍배, 백혜연, 김창수, 손영태, 권효근, 최병주, 2008. 금강하구 연안역에서 HF radar로 측정한 유속의 정확도. 한국해양학회지(바다), 13(1): 42-55.
  4. 이상호, 최현용, 손영태, 권효근, 김영곤, 양재삼, 정해진, 김종구, 2003. 하계 서해안 새만금 연안역 주변 저염수와 순환. 한국해양학회지(바다), 8(2): 138-150.
  5. Barrick, D.E., M.W. Evans, and B.L. Weber, 1977. Ocean surface currents mapped by radar, Science, 198: 138-144. https://doi.org/10.1126/science.198.4313.138
  6. Beckenbach, E., and L. Washburn, 2004. Low frequency Waves in the Santa Barbara Channel observed by high frequency radar, J, Geophys. Res., 109,c02010, doi: 10.1029/2003JC001999.
  7. Boyd, J.D., E.P. Kennelly., and P. Pistek, 1994. Estimation of EOF expansion coefficients from incomplete data, Deep Sea Res., Part I, 41(10): 1479-1488. https://doi.org/10.1016/0967-0637(94)90056-6
  8. Bretherton, F.P., R.E. Davis., and C.B. Fandry., 1976. A technique for objective analysis and design of oceanographic experiment applied to MODE-73, Deep Sea Res., 23: 559-582.
  9. Chapman, R.D., L.K. Shay, H.C. Graber, J.B. Edaon, A. Karachintsev, C.L. Trump, and D.B. Ross, 1997. On the accuracy of HFradar surface current measurements: inter-comparisons with shipbased sensors, J.Geophys. Res., 102(C8): 18,737-18,748. https://doi.org/10.1029/97JC00049
  10. Choi, B.H., 1980. A tidal model of the Yellow Sea and the Eastern China Sea. Korea Ocean Reserch and Development Institute (KORDI), Report 80-02, pp72.
  11. Emery, W.J. and R.E. Thomson, 1997. Data analysis methods in physical oceanography, Elsevier, 638 pp.
  12. Gaspari, G., Cohn, S.E., 1999. Construction of correlation functions in two and three dimensions. Quart. J. Roy Meteor Soc., 125: 723-757. https://doi.org/10.1002/qj.49712555417
  13. Haus, B.K., J.D. Wang., J. Martinez-Pedraja, and N. Smith., 2000. Remote radar measurement of shelf surrents off Key Largo, Florida, USA. Estuarine, Coastal and Shelf Sciences, 51: 533-569.
  14. Hisaki, Y., T. Tokeshi, W. Fujiie, K. Sato., and S. Fujii., 2001. Surface current variability east of Okinawa Island obtained from remotely sensed and in situ observational data. J. Geophys.Res., 106(12): 31057-31073. https://doi.org/10.1029/2000JC000784
  15. Houseago-Stokes, R.E. and P.G. Challenor., 2004. Using PPCA to estimate EOFs in the presence of missing values, J. Atmos. Oceanic Technol., 21: 1471-1480. https://doi.org/10.1175/1520-0426(2004)021<1471:UPTEEI>2.0.CO;2
  16. Kaplan D.M. and John Largier, and Louis W. Botsford, 2005. HF radar observations of surface circulation off Bodega Bay (northern California, USA), J. Geophys. Res., 110, C10020, doi:10.1029 / 2005JC002959. https://doi.org/10.1029/2005JC002959
  17. Kim, S.Y., E.J. Terrill, and B.D. Cornuelle, 2007. Objectively mapping HF radar-derived surface current data using measured and idealized data covariance matrices, J. Geophys. Res., 112: C06021, doi:10.1029/2006JC003756.
  18. Knight, P. J., Howarth, M. J., 1999. The flow through the northern channel of the Irish Sea. Continental Shelf Research, 19: 693- 713. https://doi.org/10.1016/S0278-4343(98)00110-1
  19. Kovacevic, V., M. Gacic., I. M. Mosquera., A. Mozzoldi, A. Mazzzoldi., and S. Marinetti., 2004. HF radar observations in the northern Adriatic: surface current field in front of the Venetian Lagoon. J. Marine Systems, 51: 95-122. https://doi.org/10.1016/j.jmarsys.2004.05.026
  20. Lee, S.H. and Beardsely, 1999. Influence of stratification on residual tidal currents in the Yellow Sea. J. Geophys. Res. 104(C7): 15679-15701. https://doi.org/10.1029/1999JC900108
  21. Lipa, B.J., and D.E. Barrick., 1983. Least squates methods for the extraction of surface currents from CODAR crissed-loop data: Application at ARSLOE, IEEE J. Oceanic Eng., 13(2), 507-513.
  22. Lipa, B.J., and D.E. Barrick., 1996. Comparison of direction-finding and beam-forming in HF radar ocean surface current mapping. Phase 1 SBIR Final report. Contract No. 50-DKNA-5-00092. NOAA, Rockville, MD.
  23. Lippahardt, B.L., Jr., A.D. Kirwan Jr., C.E. Grosch., J.K. Lewis., and J.D. Paduan, 2000. Blending HF radar and model velocities in Monterey Bay through normal mode analysis, J. Geophys. Res., 105(C2): 3425-3450. https://doi.org/10.1029/1999JC900295
  24. Paduan, J.D. and Graber, H.C., 1997. Introduction to HF radar, reality and myth. Oceanography, 10: 36-39. https://doi.org/10.5670/oceanog.1997.18
  25. Prandle, D. 1987. The fine structure of near shore tidal and residual circulations revealed by H.F. radar surface current measurements. J. Physical Oceanography, 17: 231-245. https://doi.org/10.1175/1520-0485(1987)017<0231:TFSONT>2.0.CO;2
  26. Son, Y.T., S.H. Lee., C.S. Kim., J.C. Lee., and G.H. Lee., 2007. Surface current variability in the Keum River Estury (South Korea) during summer 2002 as observed by high-frequency radar and coastal monitoring buoy. Continental Shelf Research, 27: 43-63. https://doi.org/10.1016/j.csr.2006.08.008
  27. Wells, D., and Beck, N., 1987. Guide to GPS positioning (second print), Canadian GPS Associates, Fredericton, N.B.

Cited by

  1. Behavior Characteristics of Floating Debris Spilled from the Nakdong River vol.30, pp.1, 2014, https://doi.org/10.7780/kjrs.2014.30.1.10