59 / 2024-09-04 09:45:15

Heat content variability of the tropical Indian Ocean induced by Indian Ocean Dipole

Ocean heat content, Indian Ocean Dipole, Indian Ocean

The ocean heat content (OHC) of the tropical Indian Ocean (TIO) shows considerable interannual variability, impacting the surrounding climate. Previous studies have mostly linked it to the Pacific El Niño-Southern Oscillation, but understanding the effects of the Indian Ocean Dipole (IOD) remains limited. Using various observational datasets and ocean model simulations, this study suggests that extreme positive IOD events can induce a net 0-2000 m OHC increase in the TIO, albeit with an east-west dipole structure. This OHC increase primarily arises from wind-driven meridional heat redistribution. Changes in surface winds over the Indian Ocean, especially in the TIO, dominate the OHC increase by driving a convergence in the tropics and a divergence in the southern Indian Ocean. These winds primarily involve anomalous equatorial easterlies and an accompanying pair of off-equatorial anticyclones. The results have implications for better predicting the regional climate extremes under the intensifying IOD events with anthropogenic warming.