Emergence of an equatorial mode of climate variability in the Indian Ocean

Pedro N DiNezio, University of Texas at Austin, Austin, TX, United States, Martin Puy, University of Texas at Austin, Institute for Geophysics, Austin, TX, United States, Kaustubh Thirumalai, University of Texas at Austin, Department of Geosciences, Tucson, United States, Jessica E Tierney, University of Arizona, Department of Geosciences, Tucson, AZ, United States and Fei-Fei Jin, University of Hawaii at Manoa, Department of Atmospheric Sciences, Honolulu, United States
Abstract:
Presently, the Indian Ocean resides in a climate state that prevents strong year-to-year climate variations. This may change under greenhouse warming, but the mechanisms remain uncertain, thus limiting our ability to predict future changes in associated climate extremes. Using climate model simulations we uncovered the emergence of a mode of climate variability capable of generating unprecedented sea-surface temperature and rainfall fluctuations across the Indian Ocean. This mode, which is inhibited under present-day conditions, becomes active in climate states with a shallow thermocline and vigorous upwelling, as predicted under continued greenhouse warming. These predictions are supported by modeling and proxy evidence of an active mode during glacial intervals that favored such a state. Due to its impact on hydrological variability, the emergence of such a mode would become a first order source of climate-related risks for the densely-populated Indian Ocean rim.
Back to: Climate Variability, Ocean Dynamics, and Biogeochemical Cycles in the Indian Ocean I