ENSO and West Pacific Seasonality Driven by the South Asian Monsoon
Name
Geophysical Research Letters - 2025 - Tuckman - ENSO and West Pacific Seasonality Driven by the South Asian Monsoon.pdf
Description
Published version
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1.93 MB
Format
Adobe PDF
Checksum (MD5)
aa0c7f330929b347d888a287d9e45a46
Author(s)
Tuckman, PJ
Smyth, Jane E
Li, Jingyuan
Lutsko, Nicholas J
Marshall, John
Date Issued
May 2, 2025
Journal
Geophysical Research Letters
Publisher
American Geophysical Union
Citation
Tuckman, P. J., Smyth, J. E., Li, J., Lutsko, N. J., & Marshall, J. (2025). ENSO and West Pacific seasonality driven by the South Asian monsoon. Geophysical Research Letters, 52, e2024GL111084.
Version
Final published version
Abstract
The equatorial Pacific exhibits a clear seasonal cycle, with West Pacific SSTs being highest during boreal autumn and El Niño/Southern Oscillation (ENSO) events tending to peak during boreal winter. In this work, we use the concept of a monsoonal mode and idealized coupled simulations to show that the presence of a large land mass in the Northern Hemisphere can lead to these seasonal asymmetries. Specifically, warm air moving east from the Asian summer monsoon suppresses surface fluxes in the West Pacific, leading to increased temperature there during the following months. The warmth of the West Pacific in boreal autumn strengthens the Walker circulation and the zonal temperature gradient across the Pacific, leading to the growth of El Niño events during that season. In summary, the presence of the Asian monsoon north of the equator results in ENSO events preferentially growing during boreal autumn and peaking during boreal winter.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution
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DOI of Published Version
10.1029/2024gl111084
