The effect of Indian Ocean temperature on the Pacific trade winds and ENSO

Ferster, B. S. ORCID: https://orcid.org/0000-0001-9241-518X, Fedorov, A. V. ORCID: https://orcid.org/0000-0001-5428-1117, Guilyardi, E. ORCID: https://orcid.org/0000-0002-2255-8625 and Mignot, J. ORCID: https://orcid.org/0000-0002-4894-898X (2023) The effect of Indian Ocean temperature on the Pacific trade winds and ENSO. Geophysical Research Letters, 50 (20). e2023GL103230. ISSN 1944-8007 doi: 10.1029/2023gl103230

Abstract/Summary

tA notable shift in the El Niño‐Southern Oscillation (ENSO) has been observed in the early 21st century, characterized by an increased prevalence of Central Pacific (CP) events and strengthened Pacific trade winds. This shift may be attributed to the warming tropical Indian Ocean (TIO). To investigate this, we conduct perturbation experiments using the Insitut Pierre Simon Laplace climate model and nudge TIO surface temperatures to induce warming or cooling effects. Our findings reveal that TIO warming (or cooling) leads to amplified (weakened) mean trade winds and surface warming (cooling) in the Pacific region. Surprisingly, ENSO variability increases in both TIO cooling and warming scenarios. This result is linked to stronger positive feedbacks and a less stable Bjerknes index for either TIO forcing. Additionally, we find that TIO warming leads to more frequent CP events, meridional widening of wind anomalies, and broadening of the ENSO power spectrum toward lower frequencies.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/114087
Identification Number/DOI	10.1029/2023gl103230
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS
Uncontrolled Keywords	General Earth and Planetary Sciences, Geophysics
Publisher	American Geophysical Union (AGU)
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