Lagrangian Approach for a New Separation Index of the East Korea Warm Current

  • Gyundo Pak
  • Young Ho KimEmail author
  • Young-Gyu Park


In this study, a separation index for the East Korea Warm Current (EKWC) is defined by Lagrangian particle tracking using surface geostrophic currents based on satellite-observed absolute dynamic topography. After determining the main stream from the inflow through the western channel of the Korea Strait, the separation index is obtained by averaging the latitude of the main particle trajectories crossing the meridian along 130.5°E. Although the separation index is obtained from coastal velocity, it describes well the surface circulation patterns in the Ulleung Basin. When it is low (i.e., the EKWC separates at low latitude), the flow toward the Japanese coast is the strongest and the EKWC is weak. In the middle phase of the separation index, a large portion of the EKWC meanders and forms the Ulleung Warm Eddy-like feature. When the separation index is high, the EKWC stretches further northward to almost 40°N. Therefore, the separation index could be used as a simple representation of the surface circulation pattern in the East/Japan Sea.


East Korea Warm Current separation index Lagrangian particle trajectory East/Japan Sea 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Chang K-I, Hogg NG, Suk M-S, Byun S-K, Kim Y-G, Kim K (2002) Mean flow and variability in the southwestern East Sea. Deep-Sea Res Pt I 49:2261–2279CrossRefGoogle Scholar
  2. Chang K-I, Teague WJ, Lyu SJ, Perkins HT, Lee DK, Watts DR, Kim YB, Mitchell DA, Lee CM, Kim K (2004) Circulation and currents in the southwestern East/Japan Sea: overview and review. Prog Oceanogr 61:105–156CrossRefGoogle Scholar
  3. Cho Y-K, Kim K (1996) Seasonal variation of the East Korea Warm Current and its relation with the cold water. La Mer 34:172–182Google Scholar
  4. Cho Y-K, Kim K (2000) Branching mechanism of the Tsushima Current in the Korea Strait. J Phys Oceanogr 30:2788–2797CrossRefGoogle Scholar
  5. Choi B-J, Haidvogel DB, Cho YK (2004) Nonseasonal sea level variations in the Japan/East Sea from satellite altimeter data. J Geophys Res-Oceans 109:C12028. doi:10.1029/2004JC002387CrossRefGoogle Scholar
  6. Choi B-J, Byun D-S, Lee K-H (2012) Satellite-altimeter-derived East Sea surface currents: estimation, description and variability pattern. J Korean Soc Oceanogr 17:225–242Google Scholar
  7. Choi B-J, Cho SH, Jung HS, Lee S-H, Byun D-S, Kwon K (2018) Interannual variation of surface circulation in the Japan/East Sea due to external forcings and intrinsic variability. Ocean Sci J 53:1–16CrossRefGoogle Scholar
  8. Dee DP, Uppala SM, Simmons AJ, Berrisford P, Poli P, Kobayashi S, Andrae U, Balmaseda MA, Balsamo G, Bauer P, Bechtold P, Beljaars ACM, van de Berg L, Bidlot J, Bormann N, Delsol C, Dragani R, Fuentes M, Geer AJ, Haimberger L, Healy SB, Hersbach H, Hólm EV, Isaksen L, Kållberg P, Köhler M, Matricardi M, McNally AP, Monge-Sanz BM, Morcrette J-J, Park B-K, Peubey C, de Rosnay P, Tavolato C, Thépaut J-N, Vitart F (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J Roy Meteor Soc 137:553–597CrossRefGoogle Scholar
  9. Frankignoul C, Sennéchael N, Kwon Y-O, Alexander MA (2011) Influence of the meridional shifts of the Kuroshio and the Oyashio Extensions on the atmospheric circulation. J Climate 24:762–777CrossRefGoogle Scholar
  10. Fukudome K-I, Yoon J-H, Ostrovskii A, Takikawa T, Han I-S (2010) Seasonal volume transport variation in the Tsushima Warm Current through the Tsushima Straits from 10 years of ADCP observations. J Oceanogr 66:539–551CrossRefGoogle Scholar
  11. Han S, Hirose N, Usui N, Miyazawa Y (2016) Multi-model ensemble estimation of volume transport through the straits of the East/Japan Sea. Ocean Dynam 66:59–76CrossRefGoogle Scholar
  12. Hogan PJ, Hurlburt HE (2000) Impact of upper ocean–topographical coupling and isopycnal outcropping in Japan/East Sea models with 1/8° to 1/64° Resolution. J Phys Oceanogr 30:2535–2561CrossRefGoogle Scholar
  13. Isobe A, Isoda Y (1997) Circulation in the Japan Basin, the northern part of the Japan Sea. J Oceanogr 53:373–381Google Scholar
  14. Jacobs GA, Hogan PJ, Whitmer KR (1999) Effects of eddy variability on the circulation of the Japan/East Sea. J Oceanogr 55:247–256CrossRefGoogle Scholar
  15. Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Leetmaa A, Reynolds R, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. B Am Meteorol Soc 77:437–471CrossRefGoogle Scholar
  16. Kang J-H, Kim W-S, Chang K-I, Noh J-H (2004) Distribution of plankton related to the mesoscale physical structure within the surface mixed layer in the southwestern East Sea, Korea. J Plankton Res 26:1515–1528CrossRefGoogle Scholar
  17. Katoh O (1994) Structure of the Tsushima Current in the southwestern Japan Sea. J Oceanogr 50:317–338CrossRefGoogle Scholar
  18. Kim K, Chang K-I, Kang D-J, Kim YH, Lee J-H (2008) Review of recent findings on the water masses and circulation in the East Sea (Sea of Japan). J Oceanogr 64:721–735CrossRefGoogle Scholar
  19. Lee D-K, Niiler P (2010) Surface circulation in the southwestern Japan/East Sea as observed from drifters and sea surface height. Deep-Sea Res Pt I 57:1222–1232CrossRefGoogle Scholar
  20. Marshall DP, Tansley CE (2001) An implicit formula for boundary current separation. J Phys Oceanogr 31:1633–1638CrossRefGoogle Scholar
  21. Min HS, Kim C-H (2006) Interannual variability and long-term trend of coastal sea surface temperature in Korea. Ocean Polar Res 28(4):415–423CrossRefGoogle Scholar
  22. Minobe S, Sako A, Nakamura M (2004) Interannual to interdecadal variability in the Japan Sea based on a new gridded upper water temperature dataset. J Phys Oceanogr 34:2382–2397CrossRefGoogle Scholar
  23. Mitchell DA, Watts DR, Wimbush M, Teague WJ, Tracey KL, Book JW, Chang KI, Suk MS, Yoon JH (2005) Upper circulation patterns in the Ulleung Basin. Deep-Sea Res Pt II 52:1617–1638CrossRefGoogle Scholar
  24. Morimoto A, Yanagi T (2001) Variability of sea surface circulation in the Japan Sea. J Oceanogr 57:1–13CrossRefGoogle Scholar
  25. Pak G, Park Y-H, Vivier F, Kwon Y-O, Chang K-I (2014) Regimedependent nonstationary relationship between the East Asian winter monsoon and North Pacific Oscillation. J Climate 27:8185–8204CrossRefGoogle Scholar
  26. Park YG (2007) The effects of Tsushima Warm Current on the interdecadal variability of the East/Japan Sea thermohaline circulation. Geophys Res Lett 34:L06609. doi:10.1029/2006GL029210Google Scholar
  27. Reynolds RW, Rayner NA, Smith TM, Stokes DC, Wang W (2002) An improved in situ and satellite SST analysis for climate. J Climate 15:1609–1625CrossRefGoogle Scholar
  28. Saraceno M, Strub PT, Kosro PM (2008) Estimates of sea surface height and near-surface alongshore coastal currents from combinations of altimeters and tide gauges. J Geophys Res-Oceans 113:C11013. doi:10.1029/2008JC004756CrossRefGoogle Scholar
  29. Seo H, Kwon Y-O, Park J-J (2014) On the effect of the East/Japan Sea SST variability on the North Pacific atmospheric circulation in a regional climate model. J Geophys Res-Atmos 119:418–444. doi:10.1002/2013JD020523CrossRefGoogle Scholar
  30. Seong K-T, Hwang J-D, Han I-S, Go W-J, Suh Y-S, Lee J-Y (2010) Characteristic for long-term trends of temperature in the Korean waters. J Korean Soc Mar Environ Saf 16(4):353–360Google Scholar
  31. Yamamoto M, Hirose N (2011) Possible modification of atmospheric circulation over the northwestern Pacific induced by a small semi-enclosed ocean. Geophy Res Lett 38:L03804. doi:10.1029/2010GL046214CrossRefGoogle Scholar

Copyright information

© Korea Institute of Ocean Science & Technology (KIOST) and the Korean Society of Oceanography (KSO) and Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.Ocean Circulation and Climate Research CenterKIOSTBusanKorea

Personalised recommendations