Abstract
The Indian Ocean Dipole (IOD), generated in the tropical Indian Ocean, fluctuates irregularly between its positive and negative phases. Given its profound impacts on regional and global climate patterns, it is crucial to understand potential IOD changes under climate change. This study investigates how the IOD pattern is modulated under global warming based on simulations from phase 6 of the Coupled Model Intercomparison Project. There is ∼6% decrease in sea surface temperature (SST) anomaly amplitude off the Sumatra coast and ∼14% increase along the equatorial eastern Indian Ocean under a high emission scenario. The reduced SST anomaly amplitude mainly stems from decreased thermodynamic air-sea feedback efficiency during positive IOD events, related to reduced mean rainfall in the east. Despite this, stronger SST anomalies along the equator are projected, due to increased zonal mixed-layer temperature advection by the mean current. For negative IOD events, increased amplitude is expected in the east, which can be attributed to enhanced zonal temperature advection and Ekman pumping term (linked to a more stratified upper ocean). These SST anomaly changes imply possible changes in IOD teleconnections and potential risks from IOD events for society and ecosystems in the face of greenhouse warming.
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