INDIAN OCEAN DECADAL VARIABILITY A Review

Experts suggest that improved definition and understanding of decadal timescale variability in the Indian Ocean region will support climate prediction efforts and have the potential to benefit a large percentage of the world's population living in Indian Ocean rim countries and elsewhere around the globe. This variability includes a rising trend from the 1960s, which is attributed to anthropogenic greenhouse gas forcing, with about 90% of the excess heat input in the climate system stored in the ocean. Defining the limits of decadal predictability and developing models capable of skillful decadal predictions rely critically on the understanding of the causes of decadal variability, including contributions from both external forcing and natural internal variations of the climate system. Observational and modeling studies have shown that decadal variability in Indian Ocean sea surface temperature (SST) can influence the tropical and extra-tropical atmosphere via changes in the Walker and Hadley circulations and in particular impact weather regimes and climate variability in the North Atlantic.