Influence of Indian ocean dipole on poleward propagation of boreal summer intraseasonal oscillations

Ajaya Ravindran, Suryachandra A. Rao, Toshio Yamagata

    Research output: Contribution to journalArticle

    Abstract

    The influence of the Indian Ocean dipole (IOD) on the poleward propagation of boreal summer intraseasonal oscillations (BSISOs) is examined using observed datasets. This study finds that coherent (incoherent) poleward propagation of precipitation anomalies from 5°S to 25°N are observed during negative (positive) IOD years. Disorganized poleward propagation of BSISO in the south equatorial Indian Ocean is observed during positive IOD years. The rationale behind such an anomaly in the poleward propagation of BSISO in contrasting IOD years is identified based on the theory of northward-propagating BSISO, which suggests the influential role of air-sea interaction on the genesis and propagation of BSISO. It is found that the mean structure of moisture convergence and meridional specific humidity distribution undergoes radical changes in contrasting IOD years, which in turn influences the meridional propagation of BSISO. This study assumes significance, considering the critical role of BSISO in modulating the seasonal mean summer monsoon rainfall.

    Original languageEnglish (US)
    Pages (from-to)5437-5454
    Number of pages18
    JournalJournal of Climate
    Volume21
    Issue number21
    DOIs
    StatePublished - Nov 1 2008

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    oscillation
    summer
    anomaly
    air-sea interaction
    Indian Ocean Dipole
    humidity
    monsoon
    moisture
    rainfall

    ASJC Scopus subject areas

    • Atmospheric Science

    Cite this

    Influence of Indian ocean dipole on poleward propagation of boreal summer intraseasonal oscillations. / Ravindran, Ajaya; Rao, Suryachandra A.; Yamagata, Toshio.

    In: Journal of Climate, Vol. 21, No. 21, 01.11.2008, p. 5437-5454.

    Research output: Contribution to journalArticle

    Ravindran, Ajaya ; Rao, Suryachandra A. ; Yamagata, Toshio. / Influence of Indian ocean dipole on poleward propagation of boreal summer intraseasonal oscillations. In: Journal of Climate. 2008 ; Vol. 21, No. 21. pp. 5437-5454.
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