Interdecadal variation of the relationship between Indian rainfall and SSTA modes in the Indian Ocean

This paper examines the relationships between Indian rainfall and the sea-surface temperature anomalies (SSTA) in different areas, including the Arabian Sea, the equatorial Indian Ocean, the southern Indian Ocean and the equatorial eastern Pacific. Their relationships have clear temporal and spatial variabilities. Before the 1980s, the correlation between Indian summer rainfall and ENSO was much stronger than the correlation between Indian summer rainfall and other SSTA. Thus, Indian summer rainfall was mainly affected by ENSO during that period. But in recent decades, ENSO has become less decisive and the Indian rain is influenced by combinations of SSTA in all the regions. The influences of the Arabian Sea on the Indian summer rainfall are affected by ENSO and are much weaker than those of the equatorial Indian Ocean and the southern Indian Ocean. SSTA in the equatorial Indian Ocean could affect rainfall over India independently. When the amplitude of SSTA in the southern Indian Ocean is large enough, SSTA in the southern Indian Ocean can play an important role in controlling rainfall, which is evident in the late 1980s. Copyright © 2006 Royal Meteorological Society.