Analysis of regional Indian rainfall: Interdecadal variability and connection with Indian Ocean SST

Monthly regional rainfall for 19 districts in India from 1861 to 1998 is examined. We investigate the interdecadal variability of the monthly contribution of each district to the June-September All-India rainfall index (AIRI). Monthly sea surface temperature (SST) from several regions within the Indian Ocean is shown to correlate strongly with both the AIRI and the regional Indian rainfall data with lead times of 3 to 6 months. The interdecadal variability of these correlations is investigated. The implications for early prediction of Indian monsoon rainfall are discussed.