Recent intensification of tropical climate variability in the Indian Ocean


The interplay of the El Niño Southern Oscillation, Asian monsoon and Indian Ocean Dipole (IOD)1,2,3 drives climatic extremes in and around the Indian Ocean. Historical4,5 and proxy6,7,8,9 records reveal changes in the behaviour of the El Niño Southern Oscillation and the Asian monsoon over recent decades10,11,12. However, reliable instrumental records of the IOD cover only the past 50 years1,3, and there is no consensus on long-term variability of the IOD or its possible response to greenhouse gas forcing13. Here we use a suite of coral oxygen-isotope records to reconstruct a basin-wide index of IOD behaviour since AD 1846. Our record reveals an increase in the frequency and strength of IOD events during the twentieth century, which is associated with enhanced seasonal upwelling in the eastern Indian Ocean. Although the El Niño Southern Oscillation has historically influenced the variability of both the IOD and the Asian monsoon3,8,10, we find that the recent intensification of the IOD coincides with the development of direct, positive IOD–monsoon feedbacks. We suggest that projected greenhouse warming may lead to a redistribution of rainfall across the Indian Ocean and a growing interdependence between the IOD and Asian monsoon precipitation variability.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: IOD climate anomalies.
Figure 2: Coral reconstruction of the DMI.
Figure 3: Twentieth-century intensification of the IOD.


  1. 1

    Saji, N. H., Goswami, B. N., Vinayachandran, P. H. & Yamagata, T. A dipole mode in the tropical Indian Ocean. Nature 401, 360–363 (1999).

    Google Scholar 

  2. 2

    Webster, P. J., Moore, M. D., Loschnigg, J. P. & Leben, R. R. Coupled ocean–atmosphere dynamics in the Indian Ocean during 1997–98. Nature 401, 356–360 (1999).

    Article  Google Scholar 

  3. 3

    Saji, N. H. & Yamagata, T. Structure of SST and surface wind variability during Indian Ocean Dipole Mode events: COADS observations. J. Clim. 2735–2751 (2003).

  4. 4

    Parthasarathy, B., Munot, A. A. & Kothawale, D. R. Contributions from Indian Institute of Tropical Meteorology, Research Report RR-065, Aug 1995, Pune 411 008, India (1995).

  5. 5

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

    Article  Google Scholar 

  6. 6

    Charles, C. D., Hunter, D. E. & Fairbanks, R. G. Interaction between the ENSO and the Asian monsoon in a coral record of tropical climate. Science 277, 925–928 (1997).

    Article  Google Scholar 

  7. 7

    Urban, F. E., Cole, J. E. & Overpeck, J. T. Influence of mean climate change on climate variability from a 155-year tropical Pacific coral record. Nature 407, 989–993 (2000).

    Article  Google Scholar 

  8. 8

    Charles, C. D., Cobb, K. M., Moore, M. D. & Fairbanks, R. G. Monsoon–tropical ocean interaction in a network of coral records spanning the 20th century. Mar. Geol. 201, 207–222 (2003).

    Article  Google Scholar 

  9. 9

    Pfeiffer, M. & Dullo, W.-C. Monsoon-induced cooling of the western equatorial Indian Ocean as recorded in coral oxygen isotope records from the Seychelles covering the period of 1840–1994 AD. Quat. Sci. Rev. 25, 993–1009 (2006).

    Article  Google Scholar 

  10. 10

    Kumar, K. K., Rajagopalan, B. & Cane, M. A. On the weakening relationship between the Indian Monsoon and ENSO. Science 284, 2156–2159 (1999).

    Article  Google Scholar 

  11. 11

    Vecchi, G. A. et al. Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing. Nature 441, 73–76 (2006).

    Article  Google Scholar 

  12. 12

    Goswami, B. N., Venugopal, V., Sengupta, D., Madhusoodanan, M. S. & Xavier, P. K. Increasing trend of extreme rain events over India in a warming environment. Science 314, 1442–1445 (2006).

    Article  Google Scholar 

  13. 13

    Conway, D., Hanson, C. E., Doherty, R. & Persechino, A. GCM simulations of the Indian Ocean dipole influence on East African rainfall: Present and future. Geophys. Res. Lett. 34, L03705 (2007).

    Article  Google Scholar 

  14. 14

    Ashok, K., Guan, Z. & Yamagata, T. Influence of the Indian Ocean Dipole on the Australian winter rainfall. Geophys. Res. Lett. 30, 1821 (2003).

    Article  Google Scholar 

  15. 15

    Abram, N. J., Gagan, M. K., McCulloch, M. T., Chappell, J. & Hantoro, W. S. Coral reef death during the 1997 Indian Ocean Dipole linked to Indonesian wildfires. Science 301, 952–955 (2003).

    Article  Google Scholar 

  16. 16

    Meyers, G., McIntosh, P., Pigot, L. & Pook, M. The years of El Niño, La Niña and interactions with the tropical Indian Ocean. J. Clim. 20, 2872–2880 (2007).

    Article  Google Scholar 

  17. 17

    Ashok, K., Guan, Z., Saji, N. H. & Yamagata, T. Individual and combined influences of ENSO and the Indian Ocean Dipole on the Indian summer monsoon. J. Clim. 17, 3141–3155 (2004).

    Article  Google Scholar 

  18. 18

    Gadgil, S., Vinayachandran, P. H., Francis, P. A. & Gadgil, S. Extremes of the Indian summer monsoon rainfall, ENSO and equatorial Indian Ocean oscillation. Geophys. Res. Lett. 31, L12213 (2004).

    Article  Google Scholar 

  19. 19

    Swapna, P. & Krishnan, R. Equatorial undercurrents associated with Indian Ocean Dipole events during contrasting summer monsoons. Geophys. Res. Lett. 35, L14S04 (2008).

    Article  Google Scholar 

  20. 20

    Abram, N. J. et al. Seasonal characteristics of the Indian Ocean Dipole during the Holocene epoch. Nature 445, 299–302 (2007).

    Article  Google Scholar 

  21. 21

    Reynolds, R. W., Rayner, N. A., Smith, T. M., Stokes, D. C. & Wang, W. An improved in situ and satellite SST analysis for climate. J. Clim. 15, 1609–1625 (2002).

    Article  Google Scholar 

  22. 22

    Fischer, A. S., Terray, P., Guilyardi, E., Gualdi, S. & Delecluse, P. Two independent triggers for the Indian Ocean Dipole/Zonal Mode in a coupled GCM. J. Clim. 18, 3428–3449 (2005).

    Article  Google Scholar 

  23. 23

    Mudelsee, M., Börngen, M., Tetzlaff, G. & Grünewald, U. No upward trends in the occurrence of extreme floods in central Europe. Nature 425, 166–169 (2003).

    Article  Google Scholar 

  24. 24

    Luo, J. J., Behera, S. K., Masumoto, Y., Sakuma, H. & Yamagata, T. Successful prediction of the consecutive IOD in 2006 and 2007. Geophys. Res. Lett. 35, L14S02 (2008).

    Article  Google Scholar 

  25. 25

    Alory, G., Wijffels, S. E. & Meyers, G. Observed temperature trends in the Indian Ocean over 1960–1999 and associated mechanisms. Geophys. Res. Lett. 34, L02606 (2007).

    Article  Google Scholar 

  26. 26

    Bakun, A. Global climate change and intensification of coastal ocean upwelling. Science 247, 198–201 (1990).

    Article  Google Scholar 

  27. 27

    McGregor, H. V., Dima, M., Fischer, H. W. & Mulitza, Rapid 20th-century increase in coastal upwelling off northwest Africa. Science 315, 637–639 (2007).

    Article  Google Scholar 

  28. 28

    Meehl, G. A. et al. in Climate Change 2007: The Physical Science Basis. Contribution of Working Group 1 to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (eds Solomon, S. et al.) 747–845 (Cambridge Univ. Press, 2007).

    Google Scholar 

  29. 29

    Xie, P. & Arkin, P. A. Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions. J. Clim. 9, 840–858 (1996).

    Article  Google Scholar 

  30. 30

    Woodruff, S. D., Diaz, H. F., Worley, S. J., Reynolds, R. W. & Lubker, S. J. Early ship observational data and ICOADS. Clim. Change 73, 169–194 (2005).

    Article  Google Scholar 

Download references


We thank B. Suwargadi, D. Prayudi, I. Suprianto, K. Glenn, T. Watanabe, H. Scott-Gagan, K. Sieh and the Indonesian Institute of Sciences (LIPI) for logistical support and technical assistance with fieldwork, which was carried out under LIPI Research Permit numbers 3551/I/KS/1999 and 2889/II/KS/2001. We also thank H. Scott-Gagan and J. Cali for laboratory assistance. C. Charles and M. Pfeiffer are thanked for providing published coral data. This study was supported by an Australian Postgraduate Award and RSES Jaeger Scholarship to N.J.A., and an Australian Research Council grant (DP0663227) to M.K.G. and W.S.H.

Author information




N.J.A. was responsible for coral geochemical analysis and interpretation of the records. M.K.G. was Chief Investigator and the Australian Institutional Counterpart for the ARC project. J.E.C. provided the spectral analysis. W.S.H. was Partner Investigator and the Indonesian Institutional Counterpart for the ARC project. M.M. assisted in statistical analysis. N.J.A., M.K.G. and J.E.C. wrote the paper.

Corresponding authors

Correspondence to Nerilie J. Abram or Michael K. Gagan.

Supplementary information

Supplementary Information, Fig. S1

Supplementary Information (PDF 1185 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Abram, N., Gagan, M., Cole, J. et al. Recent intensification of tropical climate variability in the Indian Ocean. Nature Geosci 1, 849–853 (2008).

Download citation

Further reading


Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing