National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2022

Diverse impacts of Indian Ocean dipole on El Niño-Southern Oscillation

Zhang, L., W. Han, G.A. Meehl, A. Hu, N. Rosenbloom, T. Shinoda, and M.J. McPhaden

J. Climate, 34(22), 9057–9070, doi: 10.1175/JCLI-D-21-0085.1, View online (2021)

Understanding the impact of the Indian Ocean Dipole (IOD) on El Niño-Southern Oscillation (ENSO) is important for climate prediction. By analyzing observational data and performing Indian and Pacific Ocean pacemaker experiments using a state-of-the-art climate model, we find that a positive IOD (pIOD) can favor both cold and warm sea surface temperature anomalies (SSTA) in the tropical Pacific, in contrast to the previously identified pIOD-El Niño connection. The diverse impacts of the pIOD on ENSO are related to SSTA in the Seychelles-Chagos thermocline ridge (SCTR; 60°E-85°E and 7°S-15°S) as part of the warm pole of the pIOD. Specifically, a pIOD with SCTR warming can cause warm SSTA in the southeast Indian Ocean, which induces La Niña-like conditions in the tropical Pacific through interbasin interaction processes associated with a recently identified climate phenomenon dubbed the “Warm Pool Dipole”. This study identifies a new pIOD-ENSO relationship and examines the associated mechanisms.

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