Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

The Impacts of Extra-Tropical ENSO Precursors on Tropical Pacific Decadal-scale Variability

TitleThe Impacts of Extra-Tropical ENSO Precursors on Tropical Pacific Decadal-scale Variability
Publication TypeJournal Article
Year of Publication2020
AuthorsZhou, Yingying, and Di Lorenzo Emanuele
JournalScientific Reports
Volume10
Number3031
Abstract / Summary

Off-equatorial wind anomalies on seasonal timescales from both the North and South Pacific, known as “precursors” of the El Niño Southern Oscillation (ENSO), have been shown to independently trigger the ENSO feedbacks in the tropics and its teleconnections to the extra-tropics. However, the impacts of ENSO precursors on Tropical Pacific Decadal-scale Variability (TPDV) is still not well understood and quantified. We show that the dynamic sequence from extra-tropical ENSO precursors to ENSO (tropics) to extra-tropical ENSO teleconnections is not only important for ENSO, but acts as a primary mechanism to filter (e.g. reddening) the low-frequency variability of the seasonal precursors into the decadal-scale variance of the Pacific basin, accounting for the largest fraction of the TPDV (~65%) and its phase. This process, which contrasts previous theories advocating for a TPDV generated internally in the tropics (e.g. ENSO residuals), is inherently unpredictable and not well reproduced in climate models and raises challenges for understanding and predicting the role of internal TPDV in future climate change scenarios.

URLhttps://doi.org/10.1038/s41598-020-59253-3
DOI10.1038/s41598-020-59253-3
Journal: Scientific Reports
Year of Publication: 2020
Volume: 10
Number: 3031
Publication Date: 02/2020

Off-equatorial wind anomalies on seasonal timescales from both the North and South Pacific, known as “precursors” of the El Niño Southern Oscillation (ENSO), have been shown to independently trigger the ENSO feedbacks in the tropics and its teleconnections to the extra-tropics. However, the impacts of ENSO precursors on Tropical Pacific Decadal-scale Variability (TPDV) is still not well understood and quantified. We show that the dynamic sequence from extra-tropical ENSO precursors to ENSO (tropics) to extra-tropical ENSO teleconnections is not only important for ENSO, but acts as a primary mechanism to filter (e.g. reddening) the low-frequency variability of the seasonal precursors into the decadal-scale variance of the Pacific basin, accounting for the largest fraction of the TPDV (~65%) and its phase. This process, which contrasts previous theories advocating for a TPDV generated internally in the tropics (e.g. ENSO residuals), is inherently unpredictable and not well reproduced in climate models and raises challenges for understanding and predicting the role of internal TPDV in future climate change scenarios.

DOI: 10.1038/s41598-020-59253-3
Citation:
Zhou, Y, and E Di Lorenzo.  2020.  "The Impacts of Extra-Tropical ENSO Precursors on Tropical Pacific Decadal-scale Variability."  Scientific Reports 10(3031).  https://doi.org/10.1038/s41598-020-59253-3.