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

Iskandar, Iskhaq and Irfan, M and Syamsuddin, F (2013) Why was 2008 Indian Ocean Dipole a short-lived event? Ocean Science Journal, 48 (2). pp. 1-12. ISSN 2005-7172

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    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.

    Item Type: Article
    Uncontrolled Keywords: equatorial wave, Indian Ocean Dipole, Kelvin waves, Rossby wave
    Subjects: Q Science > QC Physics
    Divisions: Faculty of Mathematics and Natural Sciences > Department of Physics
    Depositing User: Dr. Iskhaq Iskandar
    Date Deposited: 02 Feb 2015 08:47
    Last Modified: 02 Feb 2015 08:47
    URI: http://eprints.unsri.ac.id/id/eprint/5115

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