Ashok et al. (2001) identified influence of the Indian Ocean Dipole (IOD) on the interannual variability of the Indian summer monsoon rainfall (ISMR) for the period 1958-1997 (Ashok et al., 2001). The IOD and the ENSO have complementarily affected the ISMR during the last four decades. Whenever the ENSO-ISMR correlation is low (high), the IOD-ISMR correlation is high (low). The IOD plays an important role as a modulator of the Indian monsoon rainfall and influences the correlation between the ISMR and ENSO. Ashok et al, using an AGCM, have discovered that the ENSO-induced anomalous circulation over the Indian region is either countered or supported by the IOD-induced anomalous meridional circulation cell, depending upon the phase and amplitude of the two major tropical phenomena in the Indo-Pacific sector.
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| Sliding correlation (11 years window) correlation between Indian Summer Monsoon Rainfall (ISMR) and Dipole Mode Index (Magenta) and Nino3 SSTA (Turquoise) |
Reference: Ashok, K., Guan, Z., and T.Yamagata. Impact of the Indian Ocean Dipole on the relationship between the Indian monsoon rainfall and ENSO. 2001 Geophysical Research Letters, 28, 4499-4502 (Manuscript in pdf) (Figures in pdf)