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

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

DOI QR Code

Non-astronomical Tides and Monthly Mean Sea Level Variations due to Differing Hydrographic Conditions and Atmospheric Pressure along the Korean Coast from 1999 to 2017

한국 연안에서 1999년부터 2017년까지 해수물성과 대기압 변화에 따른 계절 비천문조와 월평균 해수면 변화

  • BYUN, DO-SEONG (Ocean Research Division, Korea Hydrographic and Oceanographic Agency) ;
  • CHOI, BYOUNG-JU (Department of Oceanography, Chonnam National University) ;
  • KIM, HYOWON (Ocean Research Division, Korea Hydrographic and Oceanographic Agency)
  • 변도성 (국립해양조사원 해양과학조사연구실) ;
  • 최병주 (전남대학교 해양학과) ;
  • 김효원 (국립해양조사원 해양과학조사연구실)
  • Received : 2020.09.26
  • Accepted : 2021.02.14
  • Published : 2021.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

The solar annual (Sa) and semiannual (Ssa) tides account for much of the non-uniform annual and seasonal variability observed in sea levels. These non-equilibrium tides depend on atmospheric variations, forced by changes in the Sun's distance and declination, as well as on hydrographic conditions. Here we employ tidal harmonic analyses to calculate Sa and Ssa harmonic constants for 21 Korean coastal tidal stations (TS), operated by the Korea Hydrographic and Oceanographic Agency. We used 19 year-long (1999 to 2017) 1 hr-interval sea level records from each site, and used two conventional harmonic analysis (HA) programs (Task2K and UTide). The stability of Sa harmonic constants was estimated with respect to starting date and record length of the data, and we examined the spatial distribution of the calculated Sa and Ssa harmonic constants. HA was performed on Incheon TS (ITS) records using 369-day subsets; the first start date was January 1, 1999, the subsequent data subset starting 24 hours later, and so on up until the final start date was December 27, 2017. Variations in the Sa constants produced by the two HA packages had similar magnitudes and start date sensitivity. Results from the two HA packages had a large difference in phase lag (about 78°) but relatively small amplitude (<1 cm) difference. The phase lag difference occurred in large part since Task2K excludes the perihelion astronomical variable. Sensitivity of the ITS Sa constants to data record length (i.e., 1, 2, 3, 5, 9, and 19 years) was also tested to determine the data length needed to yield stable Sa results. HA results revealed that 5 to 9 year sea level records could estimate Sa harmonic constants with relatively small error, while the best results are produced using 19 year-long records. As noted earlier, Sa amplitudes vary with regional hydrographic and atmospheric conditions. Sa amplitudes at the twenty one TS ranged from 15.0 to 18.6 cm, 10.7 to 17.5 cm, and 10.5 to 13.0 cm, along the west coast, south coast including Jejudo, and east coast including Ulleungdo, respectively. Except at Ulleungdo, it was found that the Ssa constituent contributes to produce asymmetric seasonal sea level variation and it delays (hastens) the highest (lowest) sea levels. Comparisons between monthly mean, air-pressure adjusted, and steric sea level variations revealed that year-to-year and asymmetric seasonal variations in sea levels were largely produced by steric sea level variation and inverted barometer effect.

비천문조인 연주조(Sa)와 반년주조(Ssa)는 해수특성 변화와 기상 상태에 영향을 받는 비대칭 월평균 해수면의 연변화와 관련이 깊다. 국립해양조사원이 운영하는 21개 조위관측소에서 관측한 1시간 간격의 19년(1999~2017년) 간 해수면 높이 자료에 대하여 두 종류의 조석 조화분해 프로그램(Task2K와 UTide)을 사용하여 Sa와 Ssa의 조화상수를 산출하였다. 조화분해에 사용되는 자료의 시작 시기와 길이에 따른 Sa의 안정도를 조사하였으며, Sa와 Ssa의 조화상수의 분포 특성을 살펴보았다. 먼저, 인천 조위관측소의 20년(1999~2018년) 해수면 관측자료를 1일씩 이동하면서 1년(369일) 조화분해를 수행하고 그 결과를 비교하였을 때, 두 프로그램 모두 자료의 시작 시기에 따라 Sa 조화상수가 불규칙하게 크게 변동한다는 사실을 알 수 있었다. Task2K가 Sa 분조 계산식에 근일점 천문변수를 고려하지 않아서, 두 프로그램 간에 약 78°의 지각 차가 났으며, 이들 진폭 차이는 1 cm 이하였다. 우리나라 연안에서는 Sa 조화상수가 해마다 크게 다르므로, 조위 예측 정확도와 관련하여 안정적인 조화상수 산출에 필요한 적절한 자료 길이를 결정하기 위해 관측자료 길이(1년, 2년, 3년, 5년, 9년, 19년)에 따른 인천 조위관측소의 Sa 조화상수 값의 변동성을 살펴보았다. 대표성 있는 Sa 조화상수를 구하기 위해서 조화분해를 수행할 때 5~9년 동안의 관측자료를 사용하면 조화상수 예측오차가 상당히 줄어들며, 19년 자료를 사용 것이 가장 바람직하다는 결론을 얻었다. Sa 분조의 진폭은 각 해역별로 다른 해양·대기 환경 특성에 의해 서해안에서 15.0~18.6 cm, 제주도를 포함한 남해안에서 10.7~17.5 cm이었으며, 울릉도를 포함한 동해안에서 10.5~13.0 cm이었다. 울릉도 등 동해 일부 해역을 제외하고 우리나라 연안에서 Ssa 분조의 영향으로 인해 연중 최고(최저) 해수면 높이가 발생하는 시기가 늦어(빨라)져서 해수면의 계절변화가 시간적으로 비대칭적인 특성을 보였다. 끝으로, 월평균 해수면, 대기압 보정 해수면, 비부피 높이 간 관계로부터 해수면의 해해변화와 계절변화의 비대칭성에 대기압 효과와 해수밀도가 가장 큰 영향을 끼친다는 사실을 확인하였다.

Keywords

References

  1. Bell, C., J.M. Vassie and P.L. Woodworth, 1999. POL/PSMSL Tidal Analysis Software Kit 2000 (TASK-2000). Permanent Service for Mean Sea Level, CCMS Proudman Oceanographic Laboratory, Bidston Observatory, Birkenhead, UK, 20 pp.
  2. Byun, D.-S., 2007. Overview of Tidal Phase-lag References Used in Korea. J. Korean Soc. Oceanogr., 12(3): 234-238.
  3. Byun, D.-S., B.-J. Choi and H.W. Kim, 2019. Estimation of the Lowest and Highest Astronomical Tides along the west and south coast of Korea from 1999 to 2017. J. Korean Soc. Oceanogr., 24: 495-508.
  4. Choi, B.-J., D.B. Haidvogel and Y.-K. Cho, 2009. Interannual variation of the Polar Front in the Japan/East Sea from summertime hydrography and sea level data. J. Mar. Syst., 78: 351-362. https://doi.org/10.1016/j.jmarsys.2008.11.021
  5. Carrere, L., F. Lyard, M. Cancet, A. Guillot and N. Picot, 2016. FES2014. a new tidal model- validation results and perspectives for improvements, Presentation to ESA Living Planet Conference, Prague, 2016.
  6. Codiga, D.L., 2011. Unified tidal analysis and prediction using the UTide Matlab functions. University of Rhode Island Graduate School of Oceanography Tech. Rep. 2011-01, 59 pp.
  7. Dronkers, J.J., 1964. Tidal computations in rivers and coastal waters. North-Holland Publishing Company- Amsterdam. 518 pp.
  8. Friedrichs, C.T. and D.G. Aubrey, 1988. Non-linear tidal distortion in shallow well-mixed estuaries: A synthesis. Estuarine Coastal Shelf Sci., 27: 521-545. https://doi.org/10.1016/0272-7714(88)90082-0
  9. Foreman, M.G.G., 1977. Manual for tidal heights analysis and prediction. Institute of Ocean Sciences Pacific Marine Science Rep., 77-10, 97 pp.
  10. Foreman, M.G.G., R.F. Henry, R.A. Walters and V.A. Ballantyne, 1993. A Finite Element Model for Tides and Resonance Along the North Coast of British Columbia. J. Geophys. Res., 98(C2): 2509-2531. https://doi.org/10.1029/92JC02470
  11. Foreman, M.G.G., J.Y. Cherniawsky and V.A. Ballantyne, 2009. Versatile harmonic tidal analysis: Improvements and applications. J. Atmos. Oceanic Technol., 26: 806-817, doi:10.1175/2008JTECHO615.1.
  12. Global Sea Level Observing System (GLOSS), 2011. Manual on quality control of sea level observations (Version 1). 38 pp.
  13. Godin, G., 1972. The Analysis of Tides. University of Toronto Press. 264 pp.
  14. Han, M.-H., Y.-K. Cho, H.-W. Kang, S.-H. Nam, D.-S. Byun, K.-Y. Jeong and E.I. Lee, 2020. Impacts of Atmospheric Pressure on the Annual Maximum of Monthly Sea-Levels in the Northeast Asian Marginal Seas. Journal of Marine Scince and Engineering, 8, doi:10.3390/jmse8060425.
  15. Kang, S.K., J.Y. Cherniawsky, M.G.G. Foreman and J.-K. So, 2008. Spatial variability in annual sea level variations around the Korean peninsula. Geophysical Research Letters 35: L03603, doi:10.1029/2007GL032527.
  16. Korea Hydrographic and Oceanographic Agency (KHOA), 2019. Analysis and prediction of sea level change in response to climate change around Korean peninsula (4), Busan. 385 pp (in Korean).
  17. Kim, K., Y.-K. Cho, B.-J. Choi, Y.-G. Kim and R.C. Beardsley, 2002. Sea level variability at Ulleung Island in the East (Japan) Sea. J. Geophys. Res., 107(C3), doi:10.1029/2001JC000895.
  18. Kim, Y.H. and H.S. Min, 2008. Seasonal and Interannual Variability of the North Korean Cold Current in the East Sea Reanalysis Data. Ocean and Polar Research, 30: 21-31. https://doi.org/10.4217/OPR.2008.30.1.021
  19. Ko, D.H., S.T. Jeong and H.-Y. Cho, 2016. Analysis on the Emersion and Submersion Patterns of the Coastal Zone in Korea. Journal of Korean Society of Coastal and Ocean Engineers, 28: 312-317. https://doi.org/10.9765/KSCOE.2016.28.5.312
  20. Lee, E.A., S.Y. Kim and H.S. Min, 2019. Climatological descriptions on regional circulation around the Korean Peninsula, Tellus A: Dynamic Meteorology and Oceanography, 71(1): 1604058. https://doi.org/10.1080/16000870.2019.1604058
  21. Leffler, K.E. and D.A. Jay, 2009. Enhancing tidal harmonic analysis: Robust (hybrid L1/L2) solutions. Cont. Shelf Res., 29: 78-88, doi: 10.1016/j.csr.2008.04.011.
  22. NOAA, 2009. Sea level variations of the United States 1854-2006. Technical Report NOS CO-OPS 053. Silver Spring, Maryland. pp. 37-45.
  23. Pawlowicz, R., B. Beardsley and S. Lentz, 2002. Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE. Comput. Geosci., 28: 929-937, doi:10.1016/S0098-3004(02)00013-4.
  24. Pugh, D.T., 1987. Tides, surges and mean sea level: a Handbook for Engineers and Scientists. John Wiley & Sons, New York, 472 pp.
  25. Pugh, D. and P. Woodworth, 2014. Understanding Tides, Surges, Tsunamis and Mean Sea-Level Changes. Cambridge University Press, 407 pp.
  26. Rikiishi, K. and T. Ichiye, 1986. Tidal fluctuation of the surface currents of the Kuroshio in the East China Sea. Prog. Oceanogr., 17: 193-214. https://doi.org/10.1016/0079-6611(86)90044-3
  27. Schureman, P., 1958. Manual of Harmonic Analysis and Prediction of Tides. [Revised 1940 edition reprinted 1958 with corrections, reprinted 1976]. Washington DC, United States Government Printing Office, 317 pp. (US Coast and Geodetic Survey, Special Publication 98).
  28. Zetler, B.D., E.E. Long and L.F. Ku, 1985. Tide predictions using satellite constituents. International Hydrographic Review, Monaco, LXII(2): 135-142.