Journal of Oceanography

, Volume 68, Issue 1, pp 63–77 | Cite as

The role of meso-scale eddies in mixed layer deepening and mode water formation in the western North Pacific

  • Shinya Kouketsu
  • Hiroyuki Tomita
  • Eitarou Oka
  • Shigeki Hosoda
  • Taiyo Kobayashi
  • Kanako Sato
Special Section: Original Article New developments in mode-water research: Dynamic and climatic effects


Distributions of mixed layer depths around the centers of anti-cyclonic and cyclonic eddies in the North Pacific Ocean were composited by using satellite-derived sea surface height anomaly data and Argo profiling float data. The composite distributions showed that in late winter, deeper mixed layers were more (less) frequently observed inside the cores of the anti-cyclonic (cyclonic) eddies than outside. This relationship was the clearest in the region of 140°E–160°W and 35°N–40°N, where the temperature and salinity of the deep mixed layers were similar to those of the lighter variety of central mode water (L-CMW). A simple one-dimensional bulk mixed layer model showed that both strong sea-surface heat and momentum fluxes and weak preexisting stratification contributed to formation of the deep mixed layer. These conditions were associated with the anti-cyclonic eddies, suggesting that these eddies are important in the formation of mode waters, particularly L-CMW.


Mixed layer Mode water Meso-scale eddy Sea-surface flux 



The Argo float data used in this study were collected and made freely available by the International Argo Project and the national programs that contribute to it (, The comments from anonymous reviewers were useful for improving the manuscript. This study was supported by the Japan Society for Promotion of Science (KAKENHI, Grant-in-Aid for Young Scientists (B), no. 20740279). E. Oka is supported by the Japan Society for Promotion of Science (KAKENHI, Grant-in-Aid for Scientific Research (B), no. 21340133) and the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT; Grant-in-Aid for Scientific Research of Innovative Areas under grant no. 22106007).


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Copyright information

© The Oceanographic Society of Japan and Springer 2011

Authors and Affiliations

  • Shinya Kouketsu
    • 1
  • Hiroyuki Tomita
    • 1
  • Eitarou Oka
    • 2
  • Shigeki Hosoda
    • 1
  • Taiyo Kobayashi
    • 1
  • Kanako Sato
    • 1
  1. 1.Research Institute for Global ChangeJapan Agency for Marine-Earth Science and TechnologyYokosukaJapan
  2. 2.Atmosphere and Ocean Research InstituteThe University of TokyoKashiwaJapan

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