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Article Type:
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Multidecadal-Scale Freshening at the Salinity Minimum in the Western Part of North Pacific: Importance of Wind-Driven Cross-Gyre Transport of Subarctic Water to the Subtropical Gyre

Takuya Nakanowatari Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan

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Humio Mitsudera Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan

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Tatsuo Motoi Meteorological College, Kashiwa, Chiba, Japan

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Ichiro Ishikawa Japan Meteorological Agency, Tokyo, Tokyo, Japan

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Kay I. Ohshima Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan

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Masaaki Wakatsuchi Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan

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Print Publication:
01 Apr 2015
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Climate Implications of Frontal Scale Air–Sea Interaction
DOI:
https://doi.org/10.1175/JPO-D-13-0274.1
Page(s):
988–1008
Restricted access

Abstract

Using oceanographic observations and an eddy-resolving ice–ocean coupled model simulation from 1955 to 2004, the effects of the wind-driven ocean circulation change that occurred in the late 1970s during multidecadal-scale freshening of the North Pacific Intermediate Water (NPIW) at salinity minimum density (~26.8 σθ) were investigated. An analysis of the observations revealed that salinity decreased significantly at the density range of 26.6–26.8 σθ in the western subtropical gyre, including the mixed water region (MWR). The temporal variability of the salinity is dominated by the marked change in the late 1970s. With results similar to the observations, the model, selectively forced by the interannual variability of the wind-driven ocean circulation, simulated significant freshening of the intermediate layer over the subtropical gyre. The significant freshening is related to the increase in southward transport of the Oyashio associated with the intensification of the Aleutian low. Accompanying these changes, the intrusion of fresh and low potential vorticity water, originating in the Okhotsk Sea, to the MWR increased, and the freshening signal propagated farther southward in the western subtropical gyre during the subsequent 6 yr, crossing the Kuroshio Extension. These results indicate that the multidecadal-scale freshening of the NPIW is partly caused by intensification of the wind-driven cross-gyre transport of the subarctic water to the subtropical gyre.

Corresponding author address: Takuya Nakanowatari, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan. E-mail: nakanow@jamstec.go.jp

This article is included in the Climate Implications of Frontal Scale Air–Sea Interaction Special Collection.

Abstract

Using oceanographic observations and an eddy-resolving ice–ocean coupled model simulation from 1955 to 2004, the effects of the wind-driven ocean circulation change that occurred in the late 1970s during multidecadal-scale freshening of the North Pacific Intermediate Water (NPIW) at salinity minimum density (~26.8 σθ) were investigated. An analysis of the observations revealed that salinity decreased significantly at the density range of 26.6–26.8 σθ in the western subtropical gyre, including the mixed water region (MWR). The temporal variability of the salinity is dominated by the marked change in the late 1970s. With results similar to the observations, the model, selectively forced by the interannual variability of the wind-driven ocean circulation, simulated significant freshening of the intermediate layer over the subtropical gyre. The significant freshening is related to the increase in southward transport of the Oyashio associated with the intensification of the Aleutian low. Accompanying these changes, the intrusion of fresh and low potential vorticity water, originating in the Okhotsk Sea, to the MWR increased, and the freshening signal propagated farther southward in the western subtropical gyre during the subsequent 6 yr, crossing the Kuroshio Extension. These results indicate that the multidecadal-scale freshening of the NPIW is partly caused by intensification of the wind-driven cross-gyre transport of the subarctic water to the subtropical gyre.

Corresponding author address: Takuya Nakanowatari, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan. E-mail: nakanow@jamstec.go.jp

This article is included in the Climate Implications of Frontal Scale Air–Sea Interaction Special Collection.

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  • Andreev, A., and S. Watanabe, 2002: Temporal changes in dissolved oxygen of the intermediate water in the subarctic North Pacific. Geophys. Res. Lett., 29, 1680, doi:10.1029/2002GL015021.

    • Search Google Scholar
    • Export Citation

  • Antonov, J., S. Levitus, T. P. Boyer, M. Conkright, T. O’Brien, and C. Stephens, 1998: Temperature of the Pacific Ocean. Vol. 2, World Ocean Atlas 1998, NOAA Atlas NESDIS 28, 166 pp.

  • Auad, G., J. P. Kennett, and A. J. Miller, 2003: North Pacific Intermediate Water response to a modern climate warming shift. J. Geophys. Res., 108, 3349, doi:10.1029/2003JC001987.

    • Search Google Scholar
    • Export Citation

  • Bindoff, N. L., and T. J. McDougall, 1994: Diagnosing climate change and ocean ventilation using hydrographic data. J. Phys. Oceanogr., 24, 1137–1152, doi:10.1175/1520-0485(1994)024<1137:DCCAOV>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Bindoff, N. L., and T. J. McDougall, 2000: Decadal changes along an Indian Ocean section at 32°S and their interpretation. J. Phys. Oceanogr., 30, 1207–1222, doi:10.1175/1520-0485(2000)030<1207:DCAAIO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Bond, N. A., J. E. Overland, M. Spillance, and P. Stabeno, 2003: Recent shifts in the state of the North Pacific. Geophys. Res. Lett., 30, 2183, doi:10.1029/2003GL018597.

    • Search Google Scholar
    • Export Citation

  • Boyer, T. P., S. Levitus, J. Antonov, M. Conkright, T. O’Brien, and C. Stephens, 1998: Salinity of the Pacific Ocean. Vol. 5, World Ocean Atlas 1998, NOAA Atlas NESDIS 31, 166 pp.

  • Conkright, M. E., and Coauthors, 2002: Introduction. Vol. 1, World Ocean Database 2001, NOAA Atlas NESDIS 42, 167 pp.

  • Deser, C., M. A. Alexander, and M. S. Timlin, 1996: Upper-ocean thermal variations in the North Pacific during 1970–1991. J. Climate, 9, 1840–1855, doi:10.1175/1520-0442(1996)009<1840:UOTVIT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Deser, C., M. A. Alexander, and M. S. Timlin, 1999: Evidence for a wind-driven intensification of the Kuroshio Current Extension from the 1970s to the 1980s. J. Climate, 12, 1697–1706, doi:10.1175/1520-0442(1999)012<1697:EFAWDI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Durack, P. J., and S. E. Wijffels, 2010: Fifty-year trends in global ocean salinities and their relationship to broad-scale warming. J. Climate, 23, 4342–4362, doi:10.1175/2010JCLI3377.1.

    • Search Google Scholar
    • Export Citation

  • Emerson, S., Y. W. Watanabe, T. Ono, and S. Mecking, 2004: Temporal trends in apparent oxygen utilization in the upper pycnocline of the North Pacific: 1980–2000. J. Oceanogr., 60, 139–147, doi:10.1023/B:JOCE.0000038323.62130.a0.

    • Search Google Scholar
    • Export Citation

  • Fujii, Y., T. Nakano, N. Usui, S. Matsumoto, H. Tsujino, and M. Kamachi, 2013: Pathways of the North Pacific Intermediate Water identified through the tangent linear and adjoint models of an ocean general circulation model. J. Geophys. Res. Oceans, 118, 2035–2051, doi:10.1002/jgrc.20094.

    • Search Google Scholar
    • Export Citation

  • Fujisaki, A., H. Mitsudera, and H. Yamaguchi, 2011: Dense shelf water formation process in the Sea of Okhotsk based on an ice-ocean coupled model. J. Geophys. Res., 116, C03005, doi:10.1029/2009JC006007.

    • Search Google Scholar
    • Export Citation

  • Garnier, V., and R. Schopp, 1999: Wind influence on the mesoscale activity along the Gulf Stream and the North Atlantic Currents. J. Geophys. Res., 104, 18 087–18 110, doi:10.1029/1999JC900070.

    • Search Google Scholar
    • Export Citation

  • Hill, K. L., A. J. Weaver, H. J. Freeland, and A. Bychkov, 2003: Evidence of change in the Sea of Okhotsk: Implications for the North Pacific. Atmos.–Ocean, 41, 49–63, doi:10.3137/ao.410104.

    • Search Google Scholar
    • Export Citation

  • Hunke, E. C., and J. K. Ducowicz, 1997: An elastic–viscous–plastic model for sea ice dynamics. J. Phys. Oceanogr., 27, 1849–1867, doi:10.1175/1520-0485(1997)027<1849:AEVPMF>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Ishikawa, I., and H. Ishizaki, 2009: Importance of eddy representation for modeling the intermediate salinity minimum in the North Pacific: Comparison between eddy-resolving and eddy-permitting models. J. Oceanogr., 65, 407–426, doi:10.1007/s10872-009-0036-6.

    • Search Google Scholar
    • Export Citation

  • Isoguchi, O., H. Kawamura, and T. Kono, 1997: A study on wind-driven circulation in the subarctic North Pacific using TOPEX/POSEIDON altimeter data. J. Geophys. Res., 102, 12 457–12 468, doi:10.1029/97JC00447.

    • Search Google Scholar
    • Export Citation

  • Itoh, M., 2007: Warming of intermediate water in the Sea of Okhotsk since the 1950. J. Oceanogr., 63, 637–641, doi:10.1007/s10872-007-0056-z.

    • Search Google Scholar
    • Export Citation

  • Itoh, M., K. I. Ohshima, and M. Wakatsuchi, 2003: Distribution and formation of Okhotsk Sea Intermediate Water: An analysis of isopycnal climatological data. J. Geophys. Res.,108, 3258, doi:10.1029/2002JC001590.

  • Joyce, T. M., and J. Dunworth-Baker, 2003: Long-term hydrographic variability in the Northwest Pacific Ocean. Geophys. Res. Lett., 30, 1043, doi:10.1029/2002GL015225.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E. M., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–472, doi:10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Kanamitsu, M., W. Ebisuzaki, J. Woollen, S. K. Yang, J. J. Hnilo, M. Fiorino, and G. L. Potter, 2002: NCEP–DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631–1643, doi:10.1175/BAMS-83-11-1631.

    • Search Google Scholar
    • Export Citation

  • Kashiwase, H., K. I. Ohshima, and S. Nihashi, 2014: Long-term variation in sea ice production and its relation to the intermediate water in the Sea of Okhotsk. Prog. Oceanogr., 126, 21–32, doi:10.1016/j.pocean.2014.05.004.

    • Search Google Scholar
    • Export Citation

  • Kouketsu, S., I. Yasuda, and Y. Hiroe, 2005: Observation of frontal waves and associated salinity minimum formation along the Kuroshio Extension. J. Geophys. Res., 110, C08011, doi:10.1029/2004JC002862.

    • Search Google Scholar
    • Export Citation

  • Kouketsu, S., I. Kaneko, T. Kawano, H. Uchida, T. Doi, and M. Fukasawa, 2007: Changes of North Pacific Intermediate Water properties in the subtropical gyre. Geophys. Res. Lett., 34, L02605, doi:10.1029/2006GL028499.

    • Search Google Scholar
    • Export Citation

  • Kouketsu, S., M. Fukasawa, D. Sasano, Y. Kumamoto, T. Kawano, H. Uchida, and T. Doi, 2010: Changes in water properties around North Pacific Intermediate Water between the 1980s, 1990s and 2000s. Deep-Sea Res. II, 57, 1177–1187, doi:10.1016/j.dsr2.2009.12.007.

    • Search Google Scholar
    • Export Citation

  • Levitus, S., and T. Boyer, 1994: Temperature. Vol. 4, World Ocean Atlas 1994, NOAA Atlas NESDIS 4, 150 pp.

  • Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis, 1997: A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteor. Soc., 78, 1069–1079, doi:10.1175/1520-0477(1997)078<1069:APICOW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Masujima, M., I. Yasuda, Y. Hiroe, and T. Watanabe, 2003: Transport of Oyashio water across the Subarctic Front into the mixed water region and formation of NPIW. J. Oceanogr., 59, 855–869, doi:10.1023/B:JOCE.0000009576.09079.f5.

    • Search Google Scholar
    • Export Citation

  • Matsuda, J., H. Mitsudera, T. Nakamura, K. Uchimoto, T. Nakanowatari, and N. Ebuchi, 2009: Wind and buoyancy driven intermediate-layer overturning in the Sea of Okhotsk. Deep-Sea Res. I, 56, 1401–1418, doi:10.1016/j.dsr.2009.04.014.

    • Search Google Scholar
    • Export Citation

  • Mellor, G. L., and L. Kantha, 1989: An ice-ocean coupled model. J. Geophys. Res., 94, 10 937–10 954, doi:10.1029/JC094iC08p10937.

  • Miller, A. J., D. R. Cayan, and W. B. White, 1998: A westward-intensified decadal change in the North Pacific thermocline and gyre-scale circulation. J. Climate, 11, 3112–3127, doi:10.1175/1520-0442(1998)011<3112:AWIDCI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Minobe, S., 1997: A 50–70 year climatic oscillation over the North Pacific and North America. Geophys. Res. Lett., 24, 683–686, doi:10.1029/97GL00504.

    • Search Google Scholar
    • Export Citation

  • Minobe, S., 2000: Spatio-temporal structure of the pentadecadal variability over the North Pacific. Prog. Oceanogr., 47, 381–408, doi:10.1016/S0079-6611(00)00042-2.

    • Search Google Scholar
    • Export Citation

  • Mitsudera, H., B. Taguchi, Y. Yoshikawa, H. Nakamura, T. Waseda, and T. Qu, 2004: Numerical study of the Oyashio water pathways in the Kuroshio–Oyashio confluence. J. Phys. Oceanogr., 34, 1174–1196, doi:10.1175/1520-0485(2004)034<1174:NSOTOW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Mizuta, G., Y. Fukamachi, K. I. Ohshima, and M. Wakatsuchi, 2003: Structure and seasonal variability of the East Sakhalin Current. J. Phys. Oceanogr., 33, 2430–2445, doi:10.1175/1520-0485(2003)033<2430:SASVOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Nakamura, T., T. Toyoda, Y. Ishikawa, and T. Awaji, 2006: Effects of tidal mixing at the Kuril Straits on North Pacific ventilation: Adjustment of the intermediate layer revealed from numerical experiments. J. Geophys. Res., 111, C04003, doi:10.1029/2005JC003142.

    • Search Google Scholar
    • Export Citation

  • Nakano, T., I. Kaneko, M. Endoh, and M. Kamachi, 2005: Interannual and decadal variabilities of NPIW salinity minimum core observed along JMA’s hydrographic repeat sections. J. Oceanogr., 61, 681–697, doi:10.1007/s10872-005-0076-5.

    • Search Google Scholar
    • Export Citation

  • Nakano, T., I. Kaneko, T. Soga, H. Tsujino, T. Yasuda, H. Ishizaki, and M. Kamachi, 2007: Mid-depth freshening in the North Pacific subtropical gyre observed along the JMA repeat and WOCE hydrographic sections. Geophys. Res. Lett., 34, L23608, doi:10.1029/2007GL031433.

    • Search Google Scholar
    • Export Citation

  • Nakanowatari, T., K. I. Ohshima, and M. Wakatsuchi, 2007: Warming and oxygen decrease of intermediate water in the northwestern North Pacific, originating from the Sea of Okhotsk, 1995–2004. Geophys. Res. Lett., 34, L04602, doi:10.1029/2006GL028243.

    • Search Google Scholar
    • Export Citation

  • Nakanowatari, T., H. Mitsudera, T. Motoi, K. I. Ohshima, and I. Ishikawa, 2010: 50-yr scale cooling in North Pacific Intermediate Water simulated by eddy resolving ice-ocean coupled model (in Japanese with English abstract and figure captions). Umi Sora, 85, 141–150.

    • Search Google Scholar
    • Export Citation

  • Nakanowatari, T., and Coauthors, 2014: Causes of the multidecadal-scale warming of the intermediate water in the Okhotsk Sea and western subarctic North Pacific. J. Climate, 28, 714–736, doi:10.1175/JCLI-D-14-00172.1.

    • Search Google Scholar
    • Export Citation

  • Nishioka, J., and Coauthors, 2007: Iron supply to the western subarctic Pacific: Importance of iron export from the Sea of Okhotsk. J. Geophys. Res., 112, C10012, doi:10.1029/2006JC004055.

    • Search Google Scholar
    • Export Citation

  • Nitta, T., and S. Yamada, 1989: Recent warming of tropical sea surface temperature and its relationship to the Northern Hemisphere circulation. J. Meteor. Soc. Japan, 67, 375–383.

    • Search Google Scholar
    • Export Citation

  • Nonaka, M., H. Nakamura, Y. Tanimoto, T. Kagimoto, and H. Sasaki, 2008: Interannual-to-decadal variability in the Oyashio Current and its influence on temperature in the subarctic frontal zone: An eddy-resolving OGCM simulation. J. Climate, 21, 6283–6303, doi:10.1175/2008JCLI2294.1.

    • Search Google Scholar
    • Export Citation

  • Ohshima, K. I., T. Nakanowatari, S. Riser, Y. N. Volkov, and M. Wakatsuchi, 2014: Freshening and dense shelf water reduction in the Okhotsk Sea, linked with sea ice decline. Prog. Oceanogr., 126, 71–79, doi:10.1016/j.pocean.2014.04.020.

    • Search Google Scholar
    • Export Citation

  • Ono, T., T. Midorikawa, Y. W. Watanabe, K. Tadokoro, and T. Saino, 2001: Temporal increases of phosphate and apparent oxygen utilization in the surface waters of western subarctic Pacific from 1968 to 1998. Geophys. Res. Lett., 28, 3285–3288, doi:10.1029/2001GL012948.

    • Search Google Scholar
    • Export Citation

  • Qiu, B., 2002: Large-scale variability in the midlatitude subtropical and subpolar North Pacific Ocean: Observations and causes. J. Phys. Oceanogr., 32, 353–375, doi:10.1175/1520-0485(2002)032<0353:LSVITM>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Reid, J. L., Jr., 1965: Intermediate Waters of the Pacific Ocean. Johns Hopkins Press, 85 pp.

  • Sarmiento, J. L., N. Gruber, M. A. Brzezinski, and J. P. Dunne, 2004: High latitude controls of thermocline nutrients and low latitude biological productivity. Nature, 427, 56–60, doi:10.1038/nature02127.

    • Search Google Scholar
    • Export Citation

  • Schneider, N., A. J. Miller, M. A. Alexander, and C. Deser, 1999: Subduction of decadal North Pacific temperature anomalies: Observations and dynamics. J. Phys. Oceanogr., 29, 1056–1070, doi:10.1175/1520-0485(1999)029<1056:SODNPT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sekine, Y., 1988: Anomalous southward intrusion of the Oyashio east of Japan: 1. Influence of the interannual and seasonal variations in the wind stress over the North Pacific. J. Geophys. Res., 93, 2247–2277, doi:10.1029/JC093iC03p02247.

    • Search Google Scholar
    • Export Citation

  • Shcherbina, A. Y., L. D. Talley, and D. L. Rudnick, 2003: Direct observations of North Pacific ventilation: Brine rejection in the Okhotsk Sea. Science, 302, 1952–1955, doi:10.1126/science.1088692.

    • Search Google Scholar
    • Export Citation

  • Shimizu, Y., I. Yasuda, K. Okuda, K. Hanawa, and S. Ito, 2003: ADCP-referenced Kuroshio and Oyashio water transports for North Pacific Intermediate Water formation. J. Phys. Oceanogr., 33, 220–233, doi:10.1175/1520-0485(2003)033<0220:ARKAOW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • St. Laurent, L. C., H. L. Simmons, and S. R. Jayne, 2002: Estimating tidally driven mixing in the deep ocean. Geophys. Res. Lett., 29, 2106, doi:10.1029/2002GL015633.

    • Search Google Scholar
    • Export Citation

  • Sverdrup, H. M., W. Johnson, and R. H. Fleming, 1942: The Oceans, Their Physics, Chemistry, and General Biology. Prentice-Hall, 1087 pp.

  • Talley, L. D., 1991: An Okhotsk Sea water anomaly: Implications for ventilation in the North Pacific. Deep-Sea Res.,38A, S171–S190, doi:10.1016/S0198-0149(12)80009-4.

    • Search Google Scholar
    • Export Citation

  • Talley, L. D., 1993: Distribution and formation of North Pacific Intermediate Water. J. Phys. Oceanogr., 23, 517–537, doi:10.1175/1520-0485(1993)023<0517:DAFONP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Talley, L. D., 2003: Shallow, intermediate, and deep overturning components of the global heat budget. J. Phys. Oceanogr., 33, 530–560, doi:10.1175/1520-0485(2003)033<0530:SIADOC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Talley, L. D., 2008: Freshwater transport estimates and the global overturning circulation: Shallow, deep and throughflow components. Prog. Oceanogr., 78, 257–303, doi:10.1016/j.pocean.2008.05.001.

    • Search Google Scholar
    • Export Citation

  • Talley, L. D., and Y. Nagata, 1995: The Okhotsk Sea and Oyashio region. PICES Scientific Rep. 2, 227 pp.

  • Talley, L. D., and J.-Y. Yun, 2001: The role of cabbeling and double diffusion in setting the density of the North Pacific Intermediate Water salinity minimum. J. Phys. Oceanogr., 31, 1538–1549, doi:10.1175/1520-0485(2001)031<1538:TROCAD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Tanaka, Y., T. Hibiya, and Y. Niwa, 2010: Assessment of the effects of tidal mixing in the Kuril Straits on the formation of the North Pacific Intermediate Water. J. Phys. Oceanogr., 40, 2569–2574, doi:10.1175/2010JPO4506.1.

    • Search Google Scholar
    • Export Citation

  • Tourre, Y. M., Y. Kushnir, and W. B. White, 1999: Evolution of interdecadal variability in sea level pressure, sea surface temperature, and upper ocean temperature over the Pacific Ocean. J. Phys. Oceanogr., 29, 1528–1541, doi:10.1175/1520-0485(1999)029<1528:EOIVIS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., 1990: Recent observed interdecadal climate changes in the Northern Hemisphere. Bull. Amer. Meteor. Soc., 71, 988–993, doi:10.1175/1520-0477(1990)071<0988:ROICCI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., and J. W. Hurrell, 1994: Decadal atmosphere-ocean variations in the Pacific. Climate Dyn., 9, 303–319, doi:10.1007/BF00204745.

    • Search Google Scholar
    • Export Citation

  • Van Scoy, K. A., D. B. Olson, and R. A. Fine, 1991: Ventilation of North Pacific Intermediate Waters: The role of the Alaskan Gyre. J. Geophys. Res., 96, 16 801–16 810, doi:10.1029/91JC01783.

    • Search Google Scholar
    • Export Citation

  • Wong, A. P. S., N. L. Bindoff, and J. A. Church, 1999: Large-scale freshening of intermediate waters in the Pacific and Indian Oceans. Nature, 400, 440–443, doi:10.1038/22733.

    • Search Google Scholar
    • Export Citation

  • Wong, A. P. S., N. L. Bindoff, and J. A. Church, 2001: Freshwater and heat changes in the North and South Pacific Oceans between the 1960s and 1985–94. J. Climate, 14, 1613–1633, doi:10.1175/1520-0442(2001)014<1613:FAHCIT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Wong, C. S., R. J. Matear, H. J. Freeland, F. A. Whitney, and A. S. Bychkov, 1998: WOCE line P1W in the Sea of Okhotsk: 2. CFCs and the formation rate of intermediate water. J. Geophys. Res., 103, 15 625–15 642, doi:10.1029/98JC01008.

    • Search Google Scholar
    • Export Citation

  • Yasuda, I., 1997: The origin of the North Pacific Intermediate Water. J. Geophys. Res., 102, 893–910, doi:10.1029/96JC02938.

  • Yasuda, I., 2003: Hydrographic structure and variability in the Kuroshio-Oyashio transition area. J. Oceanogr., 59, 389–402, doi:10.1023/A:1025580313836.

    • Search Google Scholar
    • Export Citation

  • Yasuda, I., K. Okuda, and Y. Shimizu, 1996: Distribution and formation of North Pacific Intermediate Water in the Kuroshio–Oyashio interfrontal zone. J. Phys. Oceanogr., 26, 448–465, doi:10.1175/1520-0485(1996)026<0448:DAMONP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Yasuda, I., S. Kouketsu, K. Katsumata, and M. Ohiwa, 2002: Influence of Okhotsk Sea Intermediate Water on the Oyashio and North Pacific Intermediate Water. J. Geophys. Res.,107, 3237, doi:10.1029/2001JC001037.

  • Yasuda, I., S. Osahune, and H. Tatebe, 2006: Possible explanation linking 18.6-year period nodal tidal cycle with bi-decadal variations of ocean and climate in the North Pacific. Geophys. Res. Lett., 33, L08606, doi:10.1029/2005GL025237.

    • Search Google Scholar
    • Export Citation

  • Yasuda, T., and K. Hanawa, 1997: Decadal changes in the mode waters in the midlatitude North Pacific. J. Phys. Oceanogr., 27, 858–870, doi:10.1175/1520-0485(1997)027,0858:DCITMW.2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • You, Y., 2003: Implications of cabbeling on the formation and transformation mechanism of North Pacific Intermediate Water. J. Geophys. Res., 108, 3134, doi:10.1029/2001JC001285.

    • Search Google Scholar
    • Export Citation

  • You, Y., N. Suginohara, M. Fukasawa, I. Yasuda, I. Kaneko, H. Yoritaka, and M. Kawamiya, 2000: Roles of the Okhotsk Sea and Gulf of Alaska in forming the North Pacific Intermediate Water. J. Geophys. Res., 105, 3253–3280, doi:10.1029/1999JC900304.

    • Search Google Scholar
    • Export Citation

  • Yun, J.-Y., and L. D. Talley, 2003: Cabbeling and the density of the North Pacific Intermediate Water quantified by an inverse method. J. Geophys. Res., 108, 3118, doi:10.1029/2002JC001482.

    • Search Google Scholar
    • Export Citation
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