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

Journal Article · Wed Feb 19 23:00:00 EST 2020 · Scientific Reports

DOI:https://doi.org/10.1038/s41598-020-59253-3· OSTI ID:1619688

Zhao, Yingying; Di Lorenzo, Emanuele

Abstract

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.

• Sponsoring Organization: USDOE
• OSTI ID: 1619688
• Journal Information: Scientific Reports, Journal Name: Scientific Reports Journal Issue: 1 Vol. 10; ISSN 2045-2322
• Publisher: Nature Publishing Group
• Country of Publication: United Kingdom
• Language: English