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Monsoons as eddy-mediated regime transitions of the tropical overturning circulation


Monsoons are generally viewed as planetary-scale sea-breeze circulations, caused by contrasts in the thermal properties between oceans and land surfaces that lead to thermal contrasts upon radiative heating1,2. But the radiative heating evolves gradually with the seasons, whereas the onset of monsoon precipitation, and the associated circulation changes such as reversal of surface winds, occur rapidly3,4. Here we use reanalysis data to show that the onset of the Asian monsoon marks a transition between two circulation regimes that are distinct in the degree to which eddy momentum fluxes control the strength of the tropical overturning circulation. Rapid transitions of the circulation between the two regimes can occur as a result of feedbacks between large-scale extratropical eddies and the tropical circulation5. Using simulations with an aquaplanet general circulation model, we demonstrate that rapid, eddy-mediated monsoon transitions occur even in the absence of surface inhomogeneities, provided the planet surface has sufficiently low thermal inertia. On the basis of these results, we propose a view of monsoons in which feedbacks between large-scale extratropical eddies and the tropical circulation are essential for the development of monsoons, whereas surface inhomogeneities such as land-sea contrasts are not.

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Figure 1: Rapid shifts of precipitation zones.
Figure 2: Observed monsoon onset over Asia.
Figure 3: Rapid changes in near-surface zonal wind at 15 N.
Figure 4: Simulated monsoon onset.


  1. Webster, P. J. in Monsoons (eds Fein, J. S. & Stephens, P. L.) 3–32 (Wiley, New York, 1987).

    Google Scholar 

  2. Webster, P. J. & Fasullo, J. Encyclopedia of Atmospheric Sciences 1370–1385 (Academic, New York, 2003).

    Book  Google Scholar 

  3. Yin, M. T. A synoptic-aerologic study of the onset of the summer monsoon over India and Burma. J. Meteorol. 6, 393–400 (1949).

    Article  Google Scholar 

  4. Lau, K.-M. & Yang, S. Seasonal variation, abrupt transition, and intraseasonal variability associated with the Asian summer monsoon in the GLA GCM. J. Clim. 9, 965–985 (1996).

    Article  Google Scholar 

  5. Schneider, T. & Bordoni, S. Eddy-mediated regime transitions in the seasonal cycle of a Hadley circulation and implications for monsoon dynamics. J. Atmos. Sci. 65, 915–934 (2008).

    Article  Google Scholar 

  6. Plumb, R. A. & Hou, A. Y. The response of a zonally symmetric atmosphere to subtropical thermal forcing: Threshold behavior. J. Atmos. Sci. 49, 1790–1799 (1992).

    Article  Google Scholar 

  7. Emanuel, K. A. On thermally direct circulations in moist atmospheres. J. Atmos. Sci. 52, 1529–1534 (1995).

    Article  Google Scholar 

  8. Plumb, R. A. in The Global Circulation of the Atmosphere (eds Schneider, T. & Sobel, A. H.) 252–266 (Princeton UP, Princeton and Oxford, 2007).

    Google Scholar 

  9. Privé, N. C. & Plumb, R. A. Monsoon dynamics with interactive forcing. Part I: Axisymmetric studies. J. Atmos. Sci. 64, 1417–1430 (2007).

    Article  Google Scholar 

  10. Gadgil, S. The Indian monsoon and its variability. Annu. Rev. Earth Planet. Sci. 31, 429–467 (2003).

    Article  Google Scholar 

  11. Li, C. & Yanai, M. The onset and interannual variability of the Asian summer monsoon in relation to land-sea thermal contrast. J. Clim. 9, 358–375 (1996).

    Article  Google Scholar 

  12. Held, I. M. & Hou, A. Y. Nonlinear axially symmetric circulations in a nearly inviscid atmosphere. J. Atmos. Sci. 37, 515–533 (1980).

    Article  Google Scholar 

  13. Lindzen, S. R. & Hou, A. Y. Hadley circulations for zonally averaged heating centered off the equator. J. Atmos. Sci. 45, 2416–2427 (1988).

    Article  Google Scholar 

  14. Schneider, T. The general circulation of the atmosphere. Annu. Rev. Earth Planet. Sci. 34, 655–688 (2006).

    Article  Google Scholar 

  15. Walker, C. C. & Schneider, T. Eddy influences on Hadley circulations: Simulations with an idealized GCM. J. Atmos. Sci. 63, 3333–3350 (2006).

    Article  Google Scholar 

  16. Webster, P. J. & Holton, J. R. Cross-equatorial response to middle-latitude forcing in a zonally varying basic state. J. Atmos. Sci. 39, 722–733 (1982).

    Article  Google Scholar 

  17. O’Gorman, P. A. & Schneider, T. The hydrological cycle over a wide range of climates simulated with an idealized GCM. J. Clim. 21, 3815–3832 (2008).

    Article  Google Scholar 

  18. Trenberth, K. E. & Caron, J. M. Estimates of meridional atmosphere and ocean heat transports. J. Clim. 14, 3433–3443 (2001).

    Article  Google Scholar 

  19. Bordoni, S. On the Role of Eddies in Monsoonal Circulations: Observations and Theory. PhD thesis, Univ. California, Los Angeles (2007).

  20. Fennessy, M. J. et al. The simulated Indian monsoon: A GCM sensitivity study. J. Clim. 7, 33–43 (1994).

    Article  Google Scholar 

  21. Chou, C., Neelin, J. D. & Su, H. Ocean-atmosphere-land feedbacks in an idealized monsoon. Q. J. R. Meteorol. Soc. 127, 1869–1891 (2001).

    Article  Google Scholar 

  22. Privé, N. C. & Plumb, R. A. Monsoon dynamics with interactive forcing. Part II: Impact of eddies and asymmetric geometries. J. Atmos. Sci. 64, 1431–1442 (2007).

    Article  Google Scholar 

  23. Chao, W. C. & Chen, B. The origin of monsoons. J. Atmos. Sci. 58, 3497–3507 (2001).

    Article  Google Scholar 

  24. Neelin, J. D., Held, I. M. & Cook, K. H. Evaporation-wind feedback and low-frequency variability in the tropical atmosphere. J. Atmos. Sci. 44, 2341–2348 (1987).

    Article  Google Scholar 

  25. Emanuel, K. A. An air–sea interaction model of intraseasonal oscillations in the tropics. J. Atmos. Sci. 44, 2324–2340 (1987).

    Article  Google Scholar 

  26. Numaguti, A. Dynamics and energy balance of the Hadley circulation and the tropical precipitation zones. Part II: Sensitivity to meridional SST distribution. J. Atmos. Sci. 52, 1128–1141 (1995).

    Article  Google Scholar 

  27. Yano, J.-I. & McBride, J. L. An aquaplanet monsoon. J. Atmos. Sci. 55, 1373–1399 (1998).

    Article  Google Scholar 

  28. Xie, S.-P. & Saiki, N. Abrupt onset and slow seasonal evolution of summer monsoon in an idealized GCM simulation. J. Meteorol. Soc. Japan 77, 949–968 (1999).

    Article  Google Scholar 

  29. Huffman, G. J. et al. Global precipitation at one-degree daily resolution from multisatellite observations. J. Hydrometeorol. 2, 36–50 (2001).

    Article  Google Scholar 

  30. Uppala, S. M. et al. The ERA-40 reanalysis. Q. J. R. Meteorol. Soc. 131, 2961–3012 (2005).

    Article  Google Scholar 

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This work was supported by the Davidow Discovery Fund, a David and Lucile Packard Fellowship, a Moore Postdoctoral Fellowship and the National Science Foundation (grant no. ATM-0450059). The simulations were carried out on Caltech’s Geological and Planetary Science Dell Cluster, and the reanalysis data were provided by the National Center for Atmospheric Research (which is sponsored by the National Science Foundation). Part of the research was carried while S.B. was with the Department of Atmospheric and Oceanic Sciences at UCLA (supported by a UCLA Dissertation Year Fellowship). We thank B. Stevens for comments on drafts of this paper.

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Bordoni, S., Schneider, T. Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nature Geosci 1, 515–519 (2008).

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