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Potential role of the February–March southern annular mode on the Indian summer monsoon rainfall: a new perspective

Prabhu, A and Kripalani, RH and Preethi, B and Pandithurai, G (2016) Potential role of the February–March southern annular mode on the Indian summer monsoon rainfall: a new perspective. Climate Dynamics, 47 (3). pp. 1161-1179.

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Abstract

Relationship between the Southern Annular Mode (SAM) and the India summer monsoon rainfall (ISMR) has been examined based on the data period 1949–2013. While the entire data period indicates a significant increasing trend in SAM, recent decades 1983–2013 indicate no trend. The relationship between the two strengthened considerably since 1983. Results reveal that the February–March SAM is significantly related with the subsequent ISMR. A positive (negative) SAM during February–March is favorable (unfavorable) for the ensuing summer monsoon rainfall over the Indian sub-continent. The delayed response is relayed through the central Pacific Ocean. We propose a hypothesis that states: when a negative (positive) phase of February–March SAM occurs, it gives rise to an anomalous meridional circulation in a longitudinally locked air–sea coupled system over the central Pacific that persists up to the subsequent boreal summer and propagates from the sub-polar latitudes to the equatorial latitudes inducing a warming (cooling) effect over the central equatorial Pacific region. In turn, this effect concomitantly weakens (strengthens) the monsoon rainfall over the Indian sub-continent. Thus, the February–March SAM could possibly serve as a new precursor to foreshadow the subsequent behavior of the Indian summer monsoon.

Item Type: Article
Additional Information: Copyright of this article belongs to Springer.
Uncontrolled Keywords: Southern Annular Mode; ENSO Modoki; Indian summer monsoon rainfall
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 08 Apr 2017 05:35
Last Modified: 08 Apr 2017 05:35
URI: http://moeseprints.incois.gov.in/id/eprint/4162

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