Underpredicted ENSO Teleconnections in Seasonal Forecasts

Abstract The El Niño‐Southern Oscillation (ENSO) influences climate variability across the globe. ENSO is highly predictable on seasonal timescales and therefore its teleconnections are a source of extratropical forecast skill. To fully harness this predictability, teleconnections must be represente...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: N. C. Williams, A. A. Scaife, J. A. Screen
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2023
Subjects:
Online Access:https://doi.org/10.1029/2022GL101689
https://doaj.org/article/44e29f4b72a74715afa9689a7eb2c0fb
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Summary:Abstract The El Niño‐Southern Oscillation (ENSO) influences climate variability across the globe. ENSO is highly predictable on seasonal timescales and therefore its teleconnections are a source of extratropical forecast skill. To fully harness this predictability, teleconnections must be represented accurately in seasonal forecasts. We find that a multimodel ensemble from five seasonal forecast systems can successfully capture the spatial structure of the late winter (JFM) El Niño teleconnection to the North Atlantic via North America, but the simulated amplitude is half of that observed. We find that weak amplitude teleconnections exist in all five models throughout the troposphere, and that the La Niña teleconnection is also weak. We find evidence that tropical forcing of the El Niño teleconnection is not underestimated and instead, deficiencies are likely to emerge in the extratropics. We investigate the impact of underestimated teleconnection strength on North Atlantic winter predictability, including its relevance to the signal‐to‐noise paradox.