Natural Hazards

, Volume 42, Issue 2, pp 273–285 | Cite as

On the impacts of ENSO and Indian Ocean dipole events on sub-regional Indian summer monsoon rainfall

  • Karumuri Ashok
  • N. H. Saji
Original paper


The relative impacts of the ENSO and Indian Ocean dipole (IOD) events on Indian summer (June–September) monsoon rainfall at sub-regional scales have been examined in this study. GISST datasets from 1958 to 1998, along with Willmott and Matsuura gridded rainfall data, all India summer monsoon rainfall data, and homogeneous and sub-regional Indian rainfall datasets were used. The spatial distribution of partial correlations between the IOD and summer rainfall over India indicates a significant impact on rainfall along the monsoon trough regions, parts of the southwest coastal regions of India, and also over Pakistan, Afghanistan, and Iran. ENSO events have a wider impact, although opposite in nature over the monsoon trough region to that of IOD events. The ENSO (IOD) index is negatively (positively) correlated (significant at the 95% confidence level from a two-tailed Student t-test) with summer monsoon rainfall over seven (four) of the eight homogeneous rainfall zones of India. During summer, ENSO events also cause drought over northern Sri Lanka, whereas the IOD events cause surplus rainfall in its south. On monthly scales, the ENSO and IOD events have significant impacts on many parts of India. In general, the magnitude of ENSO-related correlations is greater than those related to the IOD. The monthly-stratified IOD variability during each of the months from July to September has a significant impact on Indian summer monsoon rainfall variability over different parts of India, confirming that strong IOD events indeed affect the Indian summer monsoon.


Indian summer monsoon Indian Ocean dipole ENSO Impacts 



The subdivisional and homogeneous Indian rainfall sets were downloaded from, the IITM website. The figures in this paper were produced using COLA/GrADS software. The authors acknowledge Professor T. Yamagata and Drs S. K. Behera and Anguluri S. Rao for discussions.


  1. Ashok K, Guan Z, Yamagata T (2001) Impact of the Indian Ocean Dipole on the relationship between the Indian Monsoon rainfall and ENSO. Geophys Res Lett 28:4499–4502CrossRefGoogle Scholar
  2. Ashok K, Guan Z, Yamagata T (2003a) Influence of the Indian Ocean dipole on the Australian winter rainfall. Geophys Res Lett 30:1821, doi:10.1029/2003GL017926CrossRefGoogle Scholar
  3. Ashok K, Guan Z, Yamagata T (2003b) A look at the relationship between the ENSO and the Indian Ocean Dipole. J Meteor Soc Japan 81:41–56CrossRefGoogle Scholar
  4. Ashok K, Guan Z, Saji NH, Yamagata T (2004a) Individual and combined influences of the ENSO and Indian Ocean Dipole on the Indian summer monsoon. J Climate 17:3141–3155CrossRefGoogle Scholar
  5. Ashok K, Chan W-L, Motoi T, Yamagata T (2004b) Decadal variability of the Indian Ocean Dipole. Geophys Res Lett 31:L24207, doi:10.1029/2004GL021345CrossRefGoogle Scholar
  6. Behera SK, Krishnan R, Yamagata T (1999) Unusual ocean-atmosphere conditions in the tropical Indian Ocean during 1994. Geophys Res Lett 26:3001–3004CrossRefGoogle Scholar
  7. Bhaskar Rao DV, Ashok K, Yamagata T (2004) A numerical simulation study of the Indian summer monsoon of 1994 using NCAR MM5. J Meteor Soc Japan 82:1755–1775CrossRefGoogle Scholar
  8. Chang C-P, Harr P, Ju J (2001) Possible roles of Atlantic circulations on the weakening Indian monsoon rainfall-ENSO relationship. J Climate 14:2376–2380CrossRefGoogle Scholar
  9. Gadgil S, Vinayachandran PN, Francis PA (2003) Droughts of Indian summer monsoon: role of clouds over the Ocean. Curr Sci 85:1713–1719Google Scholar
  10. Gadgil S, Vinayachandran PN, Francis PA, Gadgil S (2004) Extremes of the Indian summer monsoon rainfall, ENSO, and equatorial Indian Ocean oscillation. Geophys Res Lett 31:1821, doi:10.1029/2004GL019733CrossRefGoogle Scholar
  11. Gershunov A, Schneider N, Barnett T (2001) Low frequency modulation of the ENSO-monsoon rainfall relationship: signal or noise? J Climate 14:2486–2492CrossRefGoogle Scholar
  12. Guan Z, Ashok K, Yamagata T (2003) The summertime response of the tropical atmosphere to the Indian Ocean sea surface temperature anomalies. J Meteor Soc Japan 81:533–561CrossRefGoogle Scholar
  13. Kripalani RH, Kulkarni A (1999) Climatological impact of El Niño/La Niña on the Indian monsoon: a new perspective. Weather 52:39–46Google Scholar
  14. Kripalani RH, Kumar P (2004) Northeast monsoon rainfall variability over south peninsular India vis-à-vis Indian Ocean Dipole mode. Int J Climatol 24:1267–1282CrossRefGoogle Scholar
  15. Kumar KK, Rajagopalan KB, Cane MA (1999) On the weakening relationship between the Indian monsoon and ENSO. Science 284:2156–2159CrossRefGoogle Scholar
  16. Lau N-C, Nath MJ (2004) Coupled GCM simulation of atmospheric-ocean variability associated with zonally asymmetric SST changes in the tropical Indian Ocean. J Climate 17:245–265CrossRefGoogle Scholar
  17. Legates DR, Willmott CJ (1990) Mean seasonal and spatial variability in gauge-corrected global precipitation. Int J Climatol 10:111–127CrossRefGoogle Scholar
  18. Li T, Wang B, Chang C-P, Zhang Y (2003) A theory for the Indian Ocean dipole-zonal mode. J Atmos Sci 60:2119–2135CrossRefGoogle Scholar
  19. Mooley DA, Parthasarathy B (1984) Fluctuations of all-India summer monsoon rainfall during 1871–1978. Climatic Change 6:287–301CrossRefGoogle Scholar
  20. Nicholls N (1989) Sea surface temperatures and Australian winter rainfall. J Climate 2:965–973CrossRefGoogle Scholar
  21. Nitta T, Yamada S (1989) Recent warming of tropical seas surface temperature and its relationship to the northern hemisphere circulation. J Meteorol Japan 67:375–383Google Scholar
  22. Pant GB, Parthasarathy B (1981) Some aspects of an association between the southern oscillation and Indian summer monsoon. Arch Meteor Geophys BioKlimatol Ser B 29:245–251CrossRefGoogle Scholar
  23. Pant GB, Kumar RK (1997) Climates of South Asia. J. Wiley and Sons Ltd., England, 317 ppGoogle Scholar
  24. Parthasarathy B, Kumar RK, Munot AA (1993) Homogeneous Indian monsoon rainfall: variability and prediction. Proc Ind Acad Sci 102:121–155Google Scholar
  25. Parthasarathy B, Munot AA, Kothawale DR (1994) All-India monthly and seasonal rainfall series: 1871–1993. Theor Appl Climatol 49:217–224CrossRefGoogle Scholar
  26. Parthasarathy B, Munot AA, Kothawale DR (1995) Monthly and seasonal rainfall series for all-India homogeneous regions and meteorological subdivisions: 1871–1994. IITM research report No. RR-065, available from Indian Institute of Tropical Meteorology, Pashan, Pune-411 008, IndiaGoogle Scholar
  27. Parthasarathy B, Kumar RK, Munot AA (1996) Homogeneous regional summer monsoon rainfall over India: Interannual variability and teleconnections. IITM research report No. RR70, available from the Indian Institute of Tropical Meteorology, Pashan, Pune-411 008, IndiaGoogle Scholar
  28. Patra PK, Behera SK, Herman JR, Maksyutov S, Akimoto H, Yamagata T (2005) The Indian summer monsoon rainfall: interplay of coupled dynamics, radiation, and cloud microphysics. Atmos Chem Phys 5:2181–2188CrossRefGoogle Scholar
  29. Rayner NA et al (1996) Version 2.2 of the Global sea-Ice and Sea Surface Temperature Data Set, 1903–1994. Climate Research Technical Note 74. Hadley Centre for Climate Prediction and Research, Meteorological office, London Road, Bracknell, RG12 2SYGoogle Scholar
  30. Rao AS, Behera SK, Masumoto Y, Yamagata T (2002) Interannual subsurface variability in the tropical Indian Ocean with a special emphasis on the Indian Ocean Dipole. Deep-Sea Res II 49:1549–1572CrossRefGoogle Scholar
  31. Raju PVS, Mohanty UC, Rao PLS, Bhatla R (2002) The contrasting features of Asian summer monsoon during surplus and deficient rainfall over India. Int J Climatol 22:1897–1914CrossRefGoogle Scholar
  32. Rasmusson EM, Carpenter TH (1983) The relationship between eastern equatorial Pacific sea surface temperatures and rainfall over India and Sri Lanka. Mon Wea Rev 111:517–528CrossRefGoogle Scholar
  33. Saji NH, Yamagata T (2003a) Possible impacts of Indian Ocean Dipole events on global climate. Climate Res 25:151–169CrossRefGoogle Scholar
  34. Saji NH, Yamagata T (2003b) Structure of SST and surface wind variability during Indian Ocean Dipole Mode events: COADS observations. J Climate 16:2735–2751CrossRefGoogle Scholar
  35. Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 401:360–363Google Scholar
  36. Sarkar S, Singh RP, Kafatos M (2004) Further evidences for weakening relationship of Indian rainfall and ENSO over India. Geophys Res Lett 31:L24207, doi:10.1029/2004GL020259CrossRefGoogle Scholar
  37. Sikka DR (1980) Some aspects of the large-scale fluctuations of summer monsoon rainfall over India in relation to fluctuations in planetary and regional scale circulation parameters. Proc Indian Acad Sci Earth Planet Sci 89:179–195Google Scholar
  38. Slingo JM, Annamalai H (2000) 1997: The El Niño of the century and the response of the Indian summer monsoon. Mon Wea Rev 128:1778–1797CrossRefGoogle Scholar
  39. Tozuka T, Luo J-J, Masson S, Yamagata T (2007) Decadal modulations of the Indian Ocean dipole in the SINTEX-F1 coupled GCM. J Climate (in press)Google Scholar
  40. Webster PJ et al (1998) Monsoons: processes, predictability and prospects for prediction. J Geophys Res 103:14451–14510CrossRefGoogle Scholar
  41. Webster PJ, Moore A, Loschnigg J, Leban M (1999) Coupled dynamics in the Indian Ocean during 1997–1998. Nature 401:356–360CrossRefGoogle Scholar
  42. Willmott CJ, Matsuura K (1995) Smart interpolation of annually averaged air temperature in the United States. J Appl Meteorol 34:2557–2586CrossRefGoogle Scholar
  43. Yamagata T, Behera SK, Rao SA, Guan Z, Ashok K, Saji HN (2003) Comments on “dipoles, temperature gradients, and tropical climate anomalies. Bull Amer Meteorol Soc 84:1418–1421CrossRefGoogle Scholar
  44. Yamagata T, Behera SK, Luo J-J, Masson S, Jury MR, Rao SA (2004) The coupled ocean-atmosphere variability in the tropical Indian Ocean. Earth’s climate: the ocean-atmosphere interaction. Geophys Monogr 147:189–211Google Scholar
  45. Zubair LS, Rao A, Yamagata T (2003) Modulation of Sri Lankan Maha rainfall by the Indian Ocean Dipole. Geophys Res Lett 30(2):1063, doi:10.1029/2002GL015639CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  1. 1.Frontier Research Center for Global Change (FRCGC/JAMSTEC)YokohamaJapan
  2. 2.International Pacific Research CenterUniversity of Hawaii at ManoaHonoluluUSA

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