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

Ajayamohan, RS and Rao, SA and Yamagata, T (2008) Influence of Indian ocean dipole on poleward propagation of boreal summer intraseasonal oscillations. Journal of Climate, 21 (21). pp. 5437-5454.

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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.

Item Type: Article
Additional Information: Copyright of this article belongs to American Meteorological Society
Uncontrolled Keywords: Moisture; Motion estimation; Tropical engineering; Turbulent flow, Boreal summer intraseasonal oscillations; Data sets; Equatorial indian oceans; Indian Ocean dipoles; Moisture convergences; Precipitation anomalies; Seasonal means; Specific humidities; Summer monsoons, Rain, air-sea interaction; climate oscillation; moisture; monsoon; precipitation (climatology); rainfall; summer, Indian Ocean; Indian Ocean (Equatorial)
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 18 Feb 2015 17:55
Last Modified: 18 Feb 2015 17:55

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