Advertisement

Chinese Journal of Oceanology and Limnology

, Volume 35, Issue 6, pp 1287–1302 | Cite as

Water exchange through the Kerama Gap estimated with a 25-year Pacific HYbrid Coordinate Ocean Model

  • Wenzheng Zhou (周文正)
  • Fei Yu (于非)
  • Feng Nan (南峰)
Physics
  • 70 Downloads

Abstract

Variations in water exchange through the Kerama Gap (between Okinawa Island and Miyakojima Island) from 1979 to 2003 were estimated with the 0.08° Pacific HYbrid Coordinate Ocean Model (HYCOM). The model results show that the mean transport through the Kerama Gap (KGT) from the Pacific Ocean to the East China Sea (ECS) was 2.1 Sv, which agrees well with the observed mean KGT (2.0 Sv) for 2009–2010. Over the time period examined, the monthly KGT varied from -10.9 Sv to 15.8 Sv and had a standard deviation of ± 5.0 Sv. The water mainly enters the ECS via the subsurface layer (300–500 m) along the northeastern slope of the Kerama Gap and mainly flows out of the ECS into the southwest of the Kerama Gap. The seasonal and interannual variations of the KGT and the Kuroshio upstream transport were negatively correlated. The Kuroshio upstream transport was largest in summer and smallest in autumn while the KGT was smallest in summer (1.02 Sv) and largest in spring (2.94 Sv) and autumn (2.44 Sv). The seasonal and interannual variations in the Kuroshio downstream (across the PN-line) transport differed significantly from the Kuroshio upstream transport but corresponded well with the KGT and the sum of the transport through the Kerama Gap and the Kuroshio upstream, which indicates that information about variation in the KGT is important for determining variation in the Kuroshio transport along the PN-line.

Keywords

Kerama Gap Kuroshio Ryukyu Current HYbrid Coordinate Ocean Model (HYCOM) water exchange 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Notes

Acknowledgement

The satellite-tracked drifting buoy data are available from the Global Drifter Program (GDP), with support from their website (ftp://ftp.aoml.noaa.gov/pub/phod/buoydata/). The World Ocean Database (WOD) is available from the website (http://www.nodc.noaa.gov/OC5/SELECT/dbsearch/dbsearch. html). The HYCOM data are available for download from the Global Ocean Data Assimilation Experiment (GODAE) from the website (ftp://ftp.hycom.org/datasets/PACa0.08/).

References

  1. Andres M, Park J H, Wimbush M, Zhu X H, Chang K I, Ichikawa H. 2008a. Study of the Kuroshio/Ryukyu current system based on satellite-altimeter and in situ measurements. Journal of Oceanography, 64(6): 937–950.CrossRefGoogle Scholar
  2. Andres M, Wimbush M, Park J H, Chang K I, Lim B H, Watts D R, Ichikawa H, Teague W J. 2008b. Observations of Kuroshio flow variations in the East China Sea. Journal of Geophysical Research: Oceans, 113(C5): 15.CrossRefGoogle Scholar
  3. Boyer T P, Antonov J I, Baranova O K, Garcia H E, Grodsky A, Johnson D R, Locarnini R A, Mishonov A V, O’Brien T D, Seidov D, Smolyar I V, Zweng M M. 2013. World Ocean Database 2013. Data Science Journal, 90(49): 153–173.Google Scholar
  4. Centurioni L R, Niiler P P, Lee D K. 2004. Observations of inflow of Philippine Sea surface water into the South China Sea through the Luzon Strait. Journal of Physical Oceanography, 34(1): 113–121.CrossRefGoogle Scholar
  5. Chen C T A. 2005. Tracing tropical and intermediate waters from the South China Sea to the Okinawa trough and beyond. Journal of Geophysical Research: Oceans, 110(C5): C05012.CrossRefGoogle Scholar
  6. Cummings J A, Smedstad O M. 2013. Variational data assimilation for the global ocean. In: Park S K, Xu L eds. Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications (Vol. II). Springer, Berlin Heidelberg. p.303–343.CrossRefGoogle Scholar
  7. Guo X Y, Miyazawa Y, Yamagata T. 2006. The Kuroshio onshore intrusion along the shelf break of the East China Sea: the origin of the Tsushima warm current. Journal of Physical Oceanography, 36(12): 2205–2231.CrossRefGoogle Scholar
  8. Jin B G, Wang G H, Liu Y G, Zhang R. 2010. Interaction between the East China Sea Kuroshio and the Ryukyu current as revealed by the self-organizing map. Journal of Geophysical Research: Oceans, 115(C12): 168–172.CrossRefGoogle Scholar
  9. Kelly K A, Thompson L, Cheng W, Metzger E J. 2007. Evaluation of HYCOM in the Kuroshio Extension region using new metrics. Journal of Geophysical Research: Oceans, 112(C1): 18.CrossRefGoogle Scholar
  10. Lin X P, Wu D X, Lan J. 2004. The intrusion and influences of intraseasonal long Rossby waves in the East China Sea. Journal of Hydrodynamics, 16(5): 621–632.Google Scholar
  11. Morinaga K, Nakagawa N, Osamu K, Guo B. 1998. Flow pattern of the Kuroshio west of the main Okinawa Island. In: Proceedings of Japan-China Joint Symposium on Cooperative Study of Subtropical Circulation System. Seikai National Fisheries Research Institute, Nagasaki, Japan. p.203–210.Google Scholar
  12. Na H, Wimbush M, Park J H, Nakamura H, Nishina A. 2014. Observations of flow variability through the Kerama Gap between the East China Sea and the Northwestern Pacific. Journal of Geophysical Research: Oceans, 119(2): 689–703.Google Scholar
  13. Nagano A, Ichikawa H, Miura T, Ichikawa K, Konda M, Yoshikawa Y, Obama K, Murakami K. 2007. Current system east of the Ryukyu Islands. Journal of G eophysical Research: Oceans, 112(C6): 137–154.Google Scholar
  14. Nakamura H, Nishina A, Ichikawa H, Nonaka M, Sasaki H. 2008. Deep countercurrent beneath the Kuroshio in the Okinawa Trough. Journal of Geophysical Research: Oceans, 113(C6): 1394–1404.CrossRefGoogle Scholar
  15. Nakamura H, Nishina A, Liu Z J, Tanaka F, Wimbush M, Park J H. 2013. Intermediate and deep water formation in the Okinawa Trough. Journal of Geophysical Research: Oceans, 118(12): 6881–6893.Google Scholar
  16. Oka E, Kawabe M. 1998. Characteristics of variations of water properties and density structure around the Kuroshio in the East China Sea. J ournal of O ceanography, 54(6): 605–617.Google Scholar
  17. Qu T D, Song Y T. 2009. Mindoro Strait and Sibutu Passage transports estimated from satellite data. Geophysical Research Letters, 36(9): 269–277.CrossRefGoogle Scholar
  18. Sibuet J C, Hsu S K, Shyu C T, Liu C S. 1995. Structural and kinematic evolutions of the Okinawa Trough backarc basin. In: Taylor B ed. Backarc Basins. Springer, New York. p.343–379.CrossRefGoogle Scholar
  19. Soeyanto E, Guo X Y, Ono J, Miyazawa Y. 2014. Interannual variations of Kuroshio transport in the East China Sea and its relation to the Pacific Decadal Oscillation and mesoscale eddies. Journal of Geophysical Research: Oceans, 119(6): 3595–3616.Google Scholar
  20. Song Y T. 2006. Estimation of interbasin transport using ocean bottom pressure: theory and model for Asian marginal seas. Journal of Geophysical Research: Oceans, 111(C11): 36–45.CrossRefGoogle Scholar
  21. Thoppil P G, Metzger E J, Hurlburt H E, Smedstad O M, Ichikawa H. 2016. The current system east of the Ryukyu Islands as revealed by a global ocean reanalysis. Progress in Oceanography, 141: 239–258.CrossRefGoogle Scholar
  22. You S H, Yoon J H. 2004. Modeling of the Ryukyu current along the Pacific side of the Ryukyu islands. Pacific Oceanography, 2: 44–51.Google Scholar
  23. Yu Z T, Metzger E J, Thoppil P, Hurlburt H E, Zamudio L, Smedstad O M, Na H, Nakamura H, Park J H. 2015. Seasonal cycle of volume transport through Kerama Gap revealed by a 20-year global HYbrid Coordinate Ocean Model reanalysis. Ocean Modelling, 96: 203–213.CrossRefGoogle Scholar
  24. Yuan Y. 1995. The western boundary current east of the Ryukyu Islands. Oceanographic Literature Review, 42(11): 929–930.Google Scholar
  25. Zheng X T, Liu Q Y, Hu H B, Miyazawa Y, Jia Y L. 2008. The study of the temporal and spatial characteristics of western boundary current East of Ruykyu submarne ridge and the transport of Kuroshio in East China Sea. Acta Oceanologica Sinica, 30(1): 1–9. (in Chinese with English abstract)CrossRefGoogle Scholar
  26. Zhu X H, Han I S, Park J H, Ichikawa H, Murakami K, Kaneko A, Ostrovskii A. 2003. The northeastward current southeast of Okinawa Island observed during November 2000 to August 2001. Geophysical Research Letters, 30(2): 61–79.Google Scholar

Copyright information

© Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Wenzheng Zhou (周文正)
    • 1
    • 2
  • Fei Yu (于非)
    • 1
  • Feng Nan (南峰)
    • 1
  1. 1.Institute of OceanologyChinese Academy of SciencesQingdaoChina
  2. 2.University of Chinese Academy of SciencesBeijingChina

Personalised recommendations