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https://doi.org/10.5194/egusphere-2024-1652
https://doi.org/10.5194/egusphere-2024-1652
05 Jun 2024
 | 05 Jun 2024

Tropospheric Links to Uncertainty in Stratospheric Subseasonal Predictions

Rachel W.-Y. Wu, Gabriel Chiodo, Inna Polichtchouk, and Daniela I. V. Domeisen

Abstract. Variability in the stratosphere, especially extreme events such as Sudden Stratospheric Warmings (SSWs), can impact surface weather. Understanding stratospheric prediction uncertainty is therefore crucial for skillful surface weather forecasts on weekly to monthly timescales. Using ECMWF subseasonal hindcasts, this study finds that stratospheric uncertainty is most strongly linked to tropospheric uncertainty over the North Pacific and Northern Europe, regions that can modulate but also respond to stratospheric variability, suggesting a two-way propagation of uncertainty. A case study of the 2018 SSW event shows an initial poleward and upward propagation of uncertainty from tropical convection, followed by a downward propagation where ensemble members that accurately predict the SSW also better at predicting its downward impacts. These findings highlight the locations in the troposphere that are linked to stratospheric uncertainty and suggest that improved model representation of tropospheric mechanisms linked to polar vortex variability could enhance both stratospheric and extratropical surface prediction.

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Journal article(s) based on this preprint

06 Nov 2024
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Tropospheric links to uncertainty in stratospheric subseasonal predictions
Rachel W.-Y. Wu, Gabriel Chiodo, Inna Polichtchouk, and Daniela I. V. Domeisen
Atmos. Chem. Phys., 24, 12259–12275, https://doi.org/10.5194/acp-24-12259-2024,https://doi.org/10.5194/acp-24-12259-2024, 2024
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There has been much emphasis on the increased predictability of the extratropical tropospheric...
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Strong variations in the strength of the stratospheric polar vortex can profoundly affect...
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