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GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L04706, doi:10.1029/2007GL033037, 2008

Atlantic forced component of the Indian monsoon interannual variability

F. Kucharski

Earth System Physics Section, Abdus Salam International Center for Theoretical Physics, Trieste, Italy


A. Bracco

EAS, Georgia Institute of Technology, Atlanta, Georgia, USA


J. H. Yoo

Earth System Physics Section, Abdus Salam International Center for Theoretical Physics, Trieste, Italy


F. Molteni

ECMWF, Reading, UK


Abstract

The Indian monsoon interannual variability is modulated by the El Niño Southern Oscillation (ENSO), with a drier than normal monsoon season usually preceding peak El Niño conditions, and vice versa for La Niña phase. Pacific sea surface temperature (SST) anomalies, however, are not the only player. Building upon our recent discovery that atmospheric teleconnections between the tropical Atlantic and the Indian basin contributed to the weakening of the ENSO-monsoon anticorrelation during the '80s and '90s, we investigate the role of south equatorial Atlantic SSTs in forcing the Indian monsoon rainfall (IMR). Using two observational data sets and two ensembles of simulations we show that the residual in the IMR time series for observed and modeled data, obtained by subtracting the ENSO-forced component of the IMR that is linearly related to the NINO34 index, is significantly correlated with south equatorial Atlantic SSTs. Our results have important implications for seasonal forecast efforts.

Received 18 December 2007; accepted 30 January 2008; published 27 February 2008.

Keywords: ENSO; monsoon; teleconnection.

Index Terms: 1616 Global Change: Climate variability (1635, 3305, 3309, 4215, 4513); 1620 Global Change: Climate dynamics (0429, 3309); 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 3339 Atmospheric Processes: Ocean/atmosphere interactions (0312, 4504); 3374 Atmospheric Processes: Tropical meteorology.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 1526339 bytes)

Citation: Kucharski, F., A. Bracco, J. H. Yoo, and F. Molteni (2008), Atlantic forced component of the Indian monsoon interannual variability, Geophys. Res. Lett., 35, L04706, doi:10.1029/2007GL033037.