Middle East dust as an important external driver of the Indian Ocean Dipole

The Indian Ocean Dipole (IOD) strongly influences Indo-Pacific climate extremes, yet its drivers remain incompletely understood. Using satellite observations, reanalysis, and climate model experiments, we identify Middle East dust emissions as a major external driver of IOD variability. Observational evidence shows that dust over the 1980-2020 period account for ~36% of interannual IOD variance, surpassing El Niño-Southern Oscillation as the main driver during boreal autumn. Climate simulations confirm that reduced dust enhances warming in the western Indian Ocean and inducing easterly winds that shoal the eastern thermocline. These anomalies trigger Bjerknes and wind-evaporation-sea surface temperature feedbacks, amplifying a positive IOD pattern, and vice versa. Our findings reveal a powerful dust-IOD teleconnection, highlighting the need to incorporate aerosol forcing into seasonal forecasts and climate projections.