Ocean Science Journal

, Volume 48, Issue 2, pp 149–160 | Cite as

Why was the 2008 Indian Ocean Dipole a short-lived event?

  • Iskhaq Iskandar
  • Muhammad Irfan
  • Fadli Saymsuddin
Article
  • 357 Downloads

Abstract

In this paper, the role of equatorial oceanic waves in affecting the evolution of the 2008 positive Indian Ocean Dipole (IOD) event was evaluated using available observations and output from a quasi-analytical linear wave model. It was found that the 2008 positive IOD was an early matured and abruptly terminated event: developed in April, matured in July, and diminished in September. During the development and the maturation of the 2008 positive IOD event, the wind-forced Rossby waves played a dominant role in generating zonal current anomalies in the western equatorial Indian Ocean, while a complex interplay between the wind-forced upwelling Kelvin waves and the eastern-boundary-generated Rossby waves accounted for most of the variability in the eastern basin. The latter induced eastward zonal current anomalies near the eastern boundary during the peak phase of the event. The 2008 positive IOD event was abruptly terminated in mid-July. We found that there were strong eastward zonal currents in mid-July, though the surface wind anomalies in the eastern basin continued to be westward (upwelling favorable). Our analysis shows that these eastward zonal currents mainly resulted from the easternboundary-generated upwelling Rossby waves, although the contribution from the wind-forced downwelling Kelvin waves was not negligible. These eastward zonal currents terminated the zonal heat advection and provided a favorable condition for surface heat flux to warm the eastern basin.

Key words

equatorial wave Indian Ocean Dipole Kelvin waves Rossby wave 

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References

  1. Behera SK, Luo J-J, Yamagata T (2008) Unusual IOD event of 2007. Geophys Res Lett 35:L14S11. doi:10.1029/2008GL034122CrossRefGoogle Scholar
  2. Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J Phys Oceanogr 32:2938–2954CrossRefGoogle Scholar
  3. Cai W, Pan A, Roemmich D, Cowan T, Guo X (2009) Argo profiles a rare occurrence of three consecutive positive Indian Ocean Dipole events, 2006–2008. Geophys Res Lett 36:L08701. doi: 10.1029/2008GL037038CrossRefGoogle Scholar
  4. Chambers DP, Tapley BD, Stewart RH (1999) Amomalous warming in the Indian Ocean coincident with El Niño. J Geophys Res 104:3035–3047. doi:10.1029/1998JC900085CrossRefGoogle Scholar
  5. Clarke AJ, Liu X (1993) Observations and dynamics of semiannual and annual sea level near the eastern equatorial Indian Ocean boundary. J Phys Oceanogr 23:386–399CrossRefGoogle Scholar
  6. Feng M, Meyers G (2003) Interannual variability in the tropical Indian Ocean: a two-year time-scale of Indian Ocean Dipole. Deep-Sea Res 50:2263–2284CrossRefGoogle Scholar
  7. Fu LL (2007) Intraseasonal variability of the equatorial Indian Ocean observed from sea surface height, wind, and temperature data. J Phys Oceanogr 37:188–202CrossRefGoogle Scholar
  8. Horii T, Hase H, Ueki I, Masumoto Y (2008) Oceanic precondition and evolution of the 2006 Indian Ocean Dipole. Geophys Res Lett 35:L03607. doi:10.1029/2007GL032464CrossRefGoogle Scholar
  9. Iskandar I, Masumoto Y, Mizuno K (2009) Subsurface equatorial zonal current in the eastern Indian Ocean. J Geophys Res 114:C06005. doi:10.1029/2008JC005188CrossRefGoogle Scholar
  10. Kumar BP, Vialard J, Lengaigne M, Murty VSN, McPhaden MJ (2011) TropFlux: air-sea fluxes for the global tropical oceans-description and evaluation against observations. Clim Dynam 38(7–8):1521–1543. doi:10.1007/s00382-011-1115-0Google Scholar
  11. Lau NC, Nath MJ (2003) Atmosphere-Ocean Variations in the Indo-Pacific Sector during ENSO Episodes. J Climate 16:3–20CrossRefGoogle Scholar
  12. Le Blanc J-L, Boulanger J-P (2001) Propagation and reflection of long equatorial waves in the Indian Ocean from TOPEX/POSEIDON data during 1993-1998 period. Clim Dynam 17:547–557. doi: 10.1007/s003820000128CrossRefGoogle Scholar
  13. Lee T, Fukumori I, Tang B (2004) Temperature advection: internal versus external processes. J Phys Oceanogr 34:1936–1944CrossRefGoogle Scholar
  14. McPhaden MJ, Meyers G, Ando K, Masumoto Y, Murty VSN, Ravichandran M, Syamsuddin F, Vialard J, Yu L, Yu W (2009) RAMA: The Research Moored Array for African-Asian-Australian monsoon analysis and prediction. Bull Am Meteorol Soc 90:459–480CrossRefGoogle Scholar
  15. Meyers GA, McIntosh PC, Pigot L, Pook MJ (2007) The year of El Niño, La Niña, and interactions with the tropical Indian Ocean. J Climate 20:2872–2880CrossRefGoogle Scholar
  16. Moore DW, Philander SGH (1977) Modelling of the tropical oceanic circulation. In: Goldberg ED, McCave IN, O’Brien JJ, Steele JH (eds) The Sea, vol. 6. John Wiley and Sons, pp 319–361Google Scholar
  17. Murtugudde R, McCreary JP, Busalacchi AJ (2000) Oceanic processes associated with anomalous events in the Indian Ocean with relevance to 1997-1998. J Geophys Res 105(C2):3295–3306CrossRefGoogle Scholar
  18. Nagura M, Mcphaden MJ (2010a) Wyrtki jet dynamics: Seasonal variability. J Geophys Res 115:C07009. doi:10.1029/2009JC005922CrossRefGoogle Scholar
  19. Nagura M, Mcphaden MJ (2010b) The dynamics of zonal current variations associated with the Indian Ocean Dipole. J Geophys Res 115:C11026. doi:10.1029/2010JC006423CrossRefGoogle Scholar
  20. Rao SA, 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 49:1549–1572CrossRefGoogle Scholar
  21. Rao SA, Yamagata T (2004) Abrupt termination of Indian Ocean dipole events in response to instraseasonal oscillations. Geophys Res Lett 31:L19306. doi:10.1029/2004GL020842CrossRefGoogle Scholar
  22. Rao SA, Luo J-J, Behera SK, Yamagata T (2009) Generation and termination of Indian Ocean dipole events in 2003, 2006 and 2007. Clim Dynam 33:751–767. doi:10.1007/s00382-008-0498-zCrossRefGoogle Scholar
  23. Reppin J, Schott FA, Fischer J, Quadfasel D (1999) Equatorial currents and transports in the upper central Indian Ocean: annual cycle and interannual variability. J Geophys Res 104:15495–15514. doi:10.1029/1999JC900093CrossRefGoogle Scholar
  24. Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 410:360–363Google Scholar
  25. Vinayachandran PN, Saji NH, Yamagata T (1999) Response of the equatorial Indian Ocean to an unusual wind event during 1994. Geophys Res Lett 26:1613–1616. doi:10.1029/1999GL900179CrossRefGoogle Scholar
  26. Vinayachandran PN, Kurian J, Neema CP (2007) Indian Ocean response to anomalous conditions in 2006. Geophys Res Lett 34:L15602. doi:10.1029/2007GL030194CrossRefGoogle Scholar
  27. Webster PJ, Moore AW, Loschnigg JP, Leben RR (1999) Coupled ocean-atmosphere dynamics in the Indian Ocean during 1997-1998. Nature 401:356–360CrossRefGoogle Scholar
  28. Weisberg RH, Wang C (1997) Slow variability in the equatorial west-central Pacific in relation to ENSO. J Climate 10:1998–2017CrossRefGoogle Scholar
  29. Wyrtki K (1973) An equatorial jet in the Indian Ocean. Science 181:262–264CrossRefGoogle Scholar
  30. Yamagata T, Behera SK, Luo J-J, Masson S, Jury M, Rao SA (2004) Copled ocean-atmosphere variability in the tropical Indian Ocean. Earth Climate: the Ocean-Atmosphere Interaction. AGU, Geophys Monogr No. 147, pp 189–212CrossRefGoogle Scholar
  31. Yuan D, Liu H (2009) Long-wave dynamics of sea level variations during Indian Ocean Dipole events. J Phys Oceanogr 39: 1115–1132CrossRefGoogle Scholar

Copyright information

© Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Iskhaq Iskandar
    • 1
    • 2
  • Muhammad Irfan
    • 1
  • Fadli Saymsuddin
    • 3
  1. 1.Department of Physics, Faculty of Mathematics and Natural SciencesUniversity of SriwijayaInderalaya, South SumatraIndonesia
  2. 2.Center for Geohazard and Climate Change Study, Faculty of Mathematics and Natural SciencesUniversity of SriwijayaInderalaya, South SumatraIndonesia
  3. 3.Agency for the Assessment and Application of TechnologyJakartaIndonesia

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