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Original Research Papers

Triggering of the positive Indian Ocean dipole events by severe cyclones over the Bay of Bengal

Authors:

P. A. Francis ,

Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-12, IN
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Sulochana Gadgil,

Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-12, IN
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P. N. Vinayachandran

Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-12, IN
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Abstract

In this paper, we suggest that positive Indian Ocean dipole events could be triggered by the occurrence of severe cyclones over the Bay of Bengal during April–May. All positive Indian Ocean dipole events during 1958–2003 are preceded by at least one such severe cyclone. Severe cyclones over the Bay of Bengal strengthen the meridional pressure gradient across the eastern equatorial Indian Ocean (EEIO) and hence lead to the intensification of the upwelling favourable southeasterlies along the Sumatra coast. Severe cyclones can also lead to a decrease in the integrated water vapour content and suppress convection over the EEIO. We suggest that the suppression of convection over the EEIO in turn, leads to the enhancement of convection over the western equatorial Indian Ocean (WEIO) and hence to the weakening of the westerlies along the central equatorial Indian Ocean (CEIO). This can lead to a positive feedback between suppression of convection over the EEIO and enhancement of the convergence and convection over the WEIO. If this positive feedback continues until the winds over the CEIO become easterlies, the convection over the EEIO remains suppressed for a period much longer than the synoptic scale. The strong upwelling caused by the easterlies along the equator and southeasterlies along the Sumatra coast decreases the sea surface temperature of the EEIO very rapidly and a positive dipole event gets triggered.

How to Cite: Francis, P.A., Gadgil, S. and Vinayachandran, P.N., 2007. Triggering of the positive Indian Ocean dipole events by severe cyclones over the Bay of Bengal. Tellus A: Dynamic Meteorology and Oceanography, 59(4), pp.461–475. DOI: http://doi.org/10.1111/j.1600-0870.2007.00254.x
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  Published on 01 Jan 2007
 Accepted on 10 Apr 2007            Submitted on 12 Aug 2006

References

  1. Annamalai , H. , Murtugudde , R. , Poterma , J. , Xie , S. P. , Liu , P. and co-authors . 2003. Coupled dynamics over the Indian Ocean: spring initiation of the Zonal Mode. Deep Sea Res . 50 , 2305-233 0 .  

  2. Ashok , K. , Guan , Z. and Yamagata , T. 2001 . Impact of the Indian Ocean dipole on the relationship between the Indian monsoon rainfall and ENSO . Geophys. Res. Lett . 28 , 4499 – 4502 .  

  3. Behera , S. K. , Krishnan , R. and Yamagata , T. 1999 . Unusual ocean-atmosphere conditions in the tropical Indian Ocean during 1994 . Geophys. Res. Lett . 26 , 3001 – 3004 .  

  4. Behera , S. K. , Luo , J. J. , Masson , S. , Rao , S. A. and Salcuma , H. 2006 . A CGCM Study on the interaction between IOD and ENSO . J. Climate 19 , 1688 – 1705 .  

  5. Birkett , C. , Murtugudde , R. and Allan , T. 1999 . Indian Ocean climate event brings floods to East Africa s lakes and Sudd Marsh . Geophys. Res. Lett . 26 , 1301 – 1304 .  

  6. Gadgil S. , Srinivasan , J. , Nanjundiah , R. S. , Kumar , K. K. , Munot , A. A. , and co-authors. 2002. On forecasting the Indian summer monsoon: the intriguing season of 2002 Current Sci . 4 , 394 - 403 .  

  7. Gadgil S. , Vinayachandran , P. N. and Francis , P. A. 2003 . Droughts of Indian summer monsoon: role of clouds over the Indian Ocean . Current Sc i . 85 , 1713 – 1719 .  

  8. Gadgil S. , Vinayachandran , P. N. , Francis , P. A. and Gadgil S. 2004 . Extremes of the Indian summer monsoon rainfall, ENSO and the equatorial Indian Ocean Oscillation. Geophy. Res. Lett . 31 , doi: https://doi.org/10.1029/2004GL019733 .  

  9. Gualdi S. , Guilyardi E. , Navarra A. , Masina S. and Delecluse P. 2003 . The interannual variability in the tropical Indian ocean as simulated by a CGCM . Clim. Dyn . 20 , 567 – 582 .  

  10. Han , W. , McCreary , J. P. , Anderson , D. L. T. and Mariano , A. J. 1999 . On the dynamics of the eastward surface jets in the equatorial Indian Ocean . J. Phys. Oceanogr 29 , 21917 – 22209 .  

  11. Hastenrath , S. , 2002 . Dipoles, temperature gradients and tropical climate anomalies . Bull. Amer Meteorol. Soc . 83 , 735 – 738 .  

  12. Hastenrath , S. , Nicklis , A. and Greischar , L. 1993 . Atmospheric hydrospheric mechanisms of climate anomalies in the western equatorial Indian Ocean . J. Geophys. Res . 98 , 20219 – 20235 .  

  13. Kajilcawa , Y. , Yasunari , T. and Kawamura , R. 2001 . The role of local Hadley circulation over the western Pacific on the zonally asymmetric anomalies over the Indian Ocean . J. Meteorol. Soc. Japan 81 , 259 – 276 .  

  14. Kalnay , E. , Kalnay , E. , Kanamitsua , M. , Kistlera , R. , Collinsa , and co-authors . 1996 . The NCEP/NCAR 40-y reanalysis project. Bull. Amer Meteorol. Soc . 2 , 437 - 471 .  

  15. Lau , N. C. and Nath , M. J. 2004 . Coupled GCM simulation of atmosphere-ocean variability associated with zonally asymmetric SST changes in the tropical Indian Ocean . J. Climate 17 ( 2 ), 245 – 265 .  

  16. Li , T. and Wang , B. 1994 . The influence of sea surface temperature on the tropical intraseasonal oscillation: a numerical study. Mon. Weather Re v . 122 , 2349 – 2362 .  

  17. Li , T. Wang , B. , Chang , C. P. and Zhang , Y . 2003 . A theory for the Indian Ocean dipolezonal mode. J. Atmos. Sci . 60 , 2119 - 2135 .  

  18. Liebmann , B. , Hendon , H. H. and Glick , J. D. 1994 . The relationship between tropical cyclones of the western Pacific and Indian Oceans and the Madden-Julian Oscillation . J. Meteor Soc. Japan 72 , 401 – 411 .  

  19. Liebmann , B. and Smith , C. A. 1996 . Description of a complete outgoing longwave radiation dataset . Bull. Amer Meteorol. Soc . 77 , 1275 – 1277 .  

  20. Madden , R. A. and Julian , P. R. 1971 . Detection of a 40-50 day oscillation in the zonal wind in the tropical Pacific. J. Atmos. Sc i . 28 , 702 – 708 .  

  21. Madden , R. A. and Julian , P. R. 1972 . Description of global-scale circulation cells in the tropics with a 40-50 day period. J. Atmos. Sc i . 29 , 1109 – 1123 .  

  22. Murtugudde , R. and Busalacchi , A. J. 1999 . Interannual Variability of the Dynamics and Thermodynamics of the Tropical Indian Ocean . J. Climate 12 , 2301 – 2326 .  

  23. Murtugudde , R. , McCreary , J. P. and Busalacchi , A. J. 2000 . Oceanic processes associated with anomalous events in the Indian Ocean with relevance to 1997-1998 . J. Geophys. Res . 105 , 3295 – 3306 .  

  24. Rao , S. A. and Yamagata , T. 2004 Abrupt termination of Indian Ocean dipole events in response to intraseasonal disturbances . Geophys. Res. Lett . 31 , L19306 , doi: https://doi.org/10.1029/2004GL020842 .  

  25. Reverdin , G. , Cadet , D. and Gutzler , D. 1986 . Interannual displacements of convection and surface circulation over the equatorial Indian Ocean Quart. J. Roy . Meteorol. Soc . 112 , 43 – 46 .  

  26. Reynolds , R. W. and Smith , T. M. 1995 . A high resolution global sea surface temperature climatology . J. Climate 8 , 1571 – 1583 .  

  27. Rosendal , H. 1998 . The black hole of water vapor and its use as an indicator of tropical cyclone development and intensity changes . http : //members.aol.com/Rosendalhe/black.htm .  

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

  29. Sprintal , J. , Gordon , A. R. , Murtugudde , R. and Susanto , S. D. 2000 . A semiannual Indian Ocean forced Kelvin wave observed in the Indonesian seas in May 1997 . J. Geophys. Res ., 105 , 17217 – 17230 .  

  30. Ueda , H. and Matsumoto , J. 2000 . A possible triggering process of east-west asymmetric anomalies over the Indian Ocean in relation to 1997/98 El Nino . J. Meteorol. Soc. Japan 78 , 6 , 803 – 818 .  

  31. Vinayachandran , P. N. , Saji , N. H. and Yamagata , T. 1999 . Response of the equatorial Indian Ocean to an unusual wind event during 1994 . Geophys. Res. Lett . 26 , 1613 – 1615 .  

  32. Vinayachandran , P. N. , Satoshi , I and Yamagata T. 2002. Indian Ocean dipole mode events in an ocean general circulation model Deep-Sea Res . 49 , 1573-159 6 .  

  33. Wang , B. and Rui H. 1990 . Synoptic climatology of transient tropical intraseasonal convective anomalies: 1975-1985 . Meteorol. Atmos. Phys . 44 , 43 – 61 .  

  34. Webster , P. J. , Moore , A. M. , Loschnigg , J. P. and Leben , R. R. 1999 . Coupled oceanic-atmospheric dynamics in the Indian Ocean during 1997-98 , Nature 401 , 356 – 360 .  

  35. Wyrtki , K. 1973 . An equatorial jet in the Indian Ocean . Science 181 , 262 – 264 .  

  36. Yamagata , T. , Behera , S. 2002 . The Indian Ocean dipole: a physical entity . CLI VAR Exchanges 24 , 15 – 18 .  

  37. Yamagata , T. , Behera , S. K. , Luo , J. J. , Masson , S. , Jury , M. and Rao , S. A. Coupled ocean-atmosphere variability in the tropical Indian Ocean. 2004. In: Geophys. Monogr Ser , (eds. C. Wang , S. P. Xie and J. A. Carton. American Geophysical Union, Washington, DC , 189 - 211 .  

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