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Enhanced warming of the subtropical mode water in the North Pacific and North Atlantic

Nature Climate Change volume 7, pages 656–658 (2017)Cite this article

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Abstract

Over the past six decades, the subtropical surface ocean has warmed at rates close to those of global mean surface ocean temperature1 except in western boundary current regions where the surface warming is locally enhanced by a factor of two2. Changes in the subsurface ocean, however, remain unclear because of lack of data. Compiling historical temperature measurements—some available for the first time—here we show that the subtropical mode water has warmed over the past six decades in both the North Pacific and North Atlantic. The rate of the warming is twice as large in the mode waters than at the surface. Subtropical mode waters are important water masses of vertically uniform temperature that are a few hundred metres thick and distributed widely in the main thermocline of the subtropical oceans3. The enhanced warming of subtropical mode waters can be traced back to the surface warming in the formation regions along the western boundary current extensions. Furthermore, we detect increased temperature stratification and decreased dissolved oxygen in the subtropical mode waters. The latter change has clear implications for predicting biogeochemical responses to climate warming.

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Figure 1: Warming trends versus natural variability.
Figure 2: Trends in SST.
Figure 3: Winter surface warming in western boundary currents versus subtropical subsurface warming.

References

  1. Deser, C., Phillips, A. & Alexander, M. Twentieth century tropical sea surface temperature trends revisited. Geophys. Res. Lett. 37, L10701 (2010).

    Article  Google Scholar 

  2. Wu, L. et al. Enhanced warming over the global subtropical western boundary currents. Nat. Clim. Change 2, 161–166 (2012).

    Article  CAS  Google Scholar 

  3. Hanawa, K. & Talley, L. D. in Ocean Circulation and Climate (eds Siedler, G., Church, J. & Gould, W. J.) 373–386 (Academic, 2001).

    Google Scholar 

  4. Masuzawa, J. Subtropical mode water. Deep-Sea Res. 16, 463–472 (1969).

    Google Scholar 

  5. Worthington, L. V. The 18° water in the Sargasso Sea. Deep-Sea Res. 5, 297–305 (1959).

    Google Scholar 

  6. Kwon, Y.-O. & Riser, S. C. North Atlantic subtropical mode water: a history of ocean-atmosphere interaction 1961–2000. Geophys. Res. Lett. 31, L19307 (2004).

    Article  Google Scholar 

  7. Xie, S-P., Xu, L., Liu, Q. & Kobashi, F. Dynamical role of mode water ventilation in decadal variability in the central subtropical gyre of the North Pacific. J. Clim. 24, 1212–1225 (2011).

    Article  Google Scholar 

  8. Takahashi, T. et al. Climatological mean and decadal change in surface ocean pCO2 and net sea–air CO2 flux over the global oceans. Deep-Sea Res. 56, 554–577 (2009).

    CAS  Google Scholar 

  9. Oka, E. et al. Decadal variability of subtropical mode water subduction and its impact on biogeochemistry. J. Oceanogr. 71, 389–400 (2015).

    Article  CAS  Google Scholar 

  10. Mantua, N. J. et al. A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Am. Meteorol. Soc. 78, 1069–1079 (1997).

    Article  Google Scholar 

  11. Hurrell, J. W. Decadal trends in the North Atlantic Oscillation: regional temperatures and precipitation. Science 269, 676–679 (1995).

    Article  CAS  Google Scholar 

  12. Wang, H., Xie, S.-P. & Liu, Q. Comparison of climate response to anthropogenic aerosol versus greenhouse gas forcing: distinct patterns. J. Clim. 29, 5175–5188 (2016).

    Article  Google Scholar 

  13. Frankignoul, C. & Kestenare, E. The surface heat flux feedback. Part I: estimates from observations in the Atlantic and the North Pacific. Clim. Dynam. 19, 633–647 (2002).

    Article  Google Scholar 

  14. Saba, V. S. et al. Enhanced warming of the Northwest Atlantic Ocean under climate change. J. Geophys. Res. 121, 118–132 (2016).

    Article  Google Scholar 

  15. Sun, S., Wu, L. & Qiu, B. Response of the inertial recirculation to intensified stratification in a two-layer quasigeostrophic ocean circulation model. J. Phys. Oceanogr. 43, 1254–1269 (2013).

    Article  Google Scholar 

  16. Xu, L., Xie, S-P., Liu, Q. & Kobashi, F. Response of the North Pacific subtropical countercurrent and its variability to global warming. J. Oceanogr. 68, 127–137 (2012).

    Article  Google Scholar 

  17. Karl, D. et al. The role of nitrogen fixation in biogeochemical cycling in the subtropical North Pacific Ocean. Nature 388, 533–538 (1997).

    Article  CAS  Google Scholar 

  18. Cheung, W. W. L. et al. Shrinking of fishes exacerbates impacts of global ocean changes on marine ecosystems. Nat. Clim. Change 3, 254–258 (2013).

    Article  Google Scholar 

  19. Boyer, T. P. et al. World Ocean Database 2013 NOAA Atlas NESDIS 72, 209 (eds Levitus, S. & Mishonov, A.) (Silver Spring, 2013).

  20. Akima, H. A new method of interpolation and smooth curve fitting based on local procedures. J. Assoc. Comput. Mach. 17, 589–602 (1970).

    Article  Google Scholar 

  21. Rayner, N. et al. Globally complete analyses of sea surface temperature, sea ice and night marine air temperature since the late nineteenth century. J. Geophys. Res. 108, 4407 (2003).

    Article  Google Scholar 

  22. Huang, B. et al. Extended reconstructed sea surface temperature version 4 (ERSST.v4). Part I: upgrades and intercomparisons. J. Clim. 28, 911–930 (2015).

    Article  Google Scholar 

  23. Kaplan, A. et al. Analyses of global sea surface temperature 1856–1991. J. Geophys. Res. 103, 18567–18589 (1998).

    Article  Google Scholar 

  24. Rayner, N. et al. Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: the HadSST2 data set. J. Clim. 19, 446–469 (2006).

    Article  Google Scholar 

  25. Minobe, S. & Maeda, A. A. 1degree SST dataset compiled from IOCADS from 1850 to 2002 and Northern Hemisphere frontal variability. Int. J. Climatol. 25, 881–894 (2005).

    Article  Google Scholar 

  26. Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An overview of CMIP5 and the experiment design. Bull. Am. Meteorol. Soc. 93, 485–498 (2012).

    Article  Google Scholar 

  27. Sugimoto, S. & Kako, S. I. Decadal variation in winter mixed layer depth south of the Kuroshio Extension and its influence on winter mixed layer temperature. J. Clim. 29, 1237–1252 (2016).

    Article  Google Scholar 

  28. Trenberth, K. E. et al. in Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) 235–336 (Cambridge Univ. Press, 2007).

    Google Scholar 

  29. Sen, P. K. Estimates of the regression coefficient based on Kendall’s tau. J. Am. Stat. Assoc. 63, 1379–1389 (1968).

    Article  Google Scholar 

  30. Kendall, M. G. A new measure of rank correlation. Biometrika 30, 81–93 (1938).

    Article  Google Scholar 

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Acknowledgements

S.S. is supported by a Grant-in-Aid for Young Scientists (B) (Grant 15K17756) from the Japan Society for the Promotion of Science; T.S. by the Japan Fisheries Research and Education Agency; S.-P.X. by the US National Science Foundation (1637450) Natural Science Foundation of China (41490640, 41490641), and Tohoku Forum of Creativity.

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Authors and Affiliations

  1. Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, 980-8578, Japan

    Shusaku Sugimoto

  2. Department of Geophysics, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan

    Kimio Hanawa & Toshio Suga

  3. National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, 236-8648, Japan

    Tomowo Watanabe

  4. Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA

    Shang-Ping Xie

Authors
  1. Shusaku Sugimoto
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  2. Kimio Hanawa
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  3. Tomowo Watanabe
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  4. Toshio Suga
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  5. Shang-Ping Xie
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Contributions

S.S. led this study and performed the analyses. T.S. and K.H. contributed to the development of the idea. T.W. conducted data quality control. S.S. and S.-P.X. wrote the manuscript with feedback from all authors.

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Correspondence to Shusaku Sugimoto.

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The authors declare no competing financial interests.

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Sugimoto, S., Hanawa, K., Watanabe, T. et al. Enhanced warming of the subtropical mode water in the North Pacific and North Atlantic. Nature Clim Change 7, 656–658 (2017). https://doi.org/10.1038/nclimate3371

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