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Pacific decadal oscillation and variability of the Indian summer monsoon rainfall

Krishnan, R and Sugi, M (2003) Pacific decadal oscillation and variability of the Indian summer monsoon rainfall. Climate Dynamics, 21 (3-4). pp. 233-242.

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Recent studies have furnished evidence for interdecadal variability in the tropical Pacific Ocean. The importance of this phenomenon in causing persistent anomalies over different regions of the globe has drawn considerable attention in view of its relevance in climate assessment. Here, we examine multi-source climate records in order to identify possible signatures of this longer time scale variability on the Indian summer monsoon. The findings indicate a coherent inverse relationship between the inter-decadal fluctuations of Pacific Ocean sea surface temperature (SST) and the Indian monsoon rainfall during the last century. A warm (cold) phase of the Pacific interdecadal variability is characterized by a decrease (increase) in the monsoon rainfall and a corresponding increase (decrease) in the surface air temperature over the Indian subcontinent. This interdecadal relationship can also be confirmed from the teleconnection patterns evident from long-period sea level pressure (SLP) dataset. The SLP anomalies over South and Southeast Asia and the equatorial west Pacific are dynamically consistent in showing an out-of-phase pattern with the SLP anomalies over the tropical central-eastern Pacific. The remote influence of the Pacific interdecadal variability on the monsoon is shown to be associated with prominent signals in the tropical and southern Indian Ocean indicative of coherent inter-basin variability on decadal time scales. If indeed, the atmosphere-ocean coupling associated with the Pacific interdecadal variability is independent from that of the interannual El Niño-Southern Oscillation (ENSO), then the climate response should depend on the evolutionary characteristics of both the time scales. It is seen from our analysis that the Indian monsoon is more vulnerable to drought situations, when El Niño events occur during warm phases of the Pacific interdecadal variability. Conversely, wet monsoons are more likely to prevail, when La Nino events coincide during cold phases of the Pacific interdecadal variability.

Item Type: Article
Additional Information: Copyright of this article belongs to Springer.
Uncontrolled Keywords: atmosphere-ocean coupling; climate variation; decadal variation; El Nino-Southern Oscillation; monsoon; sea surface temperature, Pacific Ocean
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 19 Apr 2015 12:00
Last Modified: 19 Apr 2015 12:00

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