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Indian Ocean-monsoon coupled interactions and impending monsoon droughts

Krishnan, R and Ramesh, KV and Samala, BK and Meyers, G and Slingo, JM and Fennessy, MJ (2006) Indian Ocean-monsoon coupled interactions and impending monsoon droughts. Geophysical Research Letters, 33 (8).

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Monsoon droughts over the Indian subcontinent emanate from failures in the seasonal (June-September) monsoon rains. While prolonged dry-spells ("monsoonbreaks") pervade on sub-seasonal/intra-seasonal time-scales, the underlying causes for these long-lasting anomalies remain elusive. Based on analyses of a suite of observed data sets, we report an ocean-atmosphere dynamical coupling on intra-seasonal time-scales, in the tropical Indian Ocean, which is pivotal in forcing extended monsoon-breaks and causing droughts over the subcontinent. This coupling involves a feedback between the monsoonal flow and thermocline depth in the Equatorial Eastern Indian Ocean (EEIO), in which an anomaly of the summer monsoon circulation induces downwelling and maintains a higher-than-normal heat-content. The near-equatorial anomalies induce strong and sustained suppression of monsoon rainfall over the subcontinent. It is concluded that the intraseasonal evolution of the ocean-monsoon coupled system is a vital key to unlocking the dynamics of monsoon droughts.

Item Type: Article
Additional Information: Copyright of this article belongs to American Geophysical Union.
Uncontrolled Keywords: Drought; Dynamics; Mathematical models; Rain; Tropics, Intra-seasonal time-scales; Monsoon circulation; Monsoon droughts; Monsoon rains; Ocean-atmosphere dynamical coupling; Ocean-monsoon, Oceanography, atmosphere-ocean coupling; atmospheric circulation; drought; monsoon; oceanic circulation, Indian Ocean
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 18 Dec 2014 10:24
Last Modified: 18 Dec 2014 10:24

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