nextGEMS - Next Generation Earth Modelling Systems

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Published August 7, 2023 | Version v1
Journal article Open

Tropospheric Role in the Predictability of the Surface Impact of the 2018 Sudden Stratospheric Warming Event

Authors/Creators

  • 1. Departamento de Física de la Tierra y Astrofísica, Universidad Complutense de Madrid, Madrid, Spain; Instituto de Geociencias (IGEO), UCM-CSIC, Madrid, Spain
  • 2. Department Troposphere Research, Institute of Meteorology and Climate Research (IMK-TRO), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
  • 3. Departamento de Física de la Tierra y Astrofísica, Universidad Complutense de Madrid, Madrid, Spain
  • 4. ETH Zurich, Institute for Atmospheric and Climate Science, Zurich, Switzerland; University of Lausanne, Lausanne, Switzerland
  • 5. European Centre for Medium-Range Weather Forecasts, Reading, UK

Description

Abstract

Sudden stratospheric warmings (SSWs) can have a strong impact on the troposphere. Their fingerprint is often associated with the negative phase of the Northern Annular Mode (NAM) and the North Atlantic Oscillation (NAO), and extreme weather with high societal impact. However, the mechanisms behind this downward impact are not well understood. We investigate this surface impact through its associated predictability limits, by studying the 2018 SSW event. We search for predictability barriers that occurred after the onset of the SSW and before its surface impact. It is found that dynamical tropospheric events consisting of two cyclogenesis events were the main reasons for these predictability barriers in the prediction of negative NAM/NAO anomalies reaching the surface. This work corroborates that individual synoptic events might constitute predictability barriers during the downward impact of SSW events, and thereby sheds light on stratosphere-troposphere coupling.

 

Plain Language Summary

Sudden stratospheric warmings (SSWs) can have a strong impact on near-surface weather. They have the potential to alter the atmospheric circulation and associated extreme events, thus affecting society. However, the way the stratosphere couples with surface weather is not fully understood. In this work, we investigate this relationship by analyzing the predictability of the surface impact of a stratospheric warming event that occurred in 2018, and which left widespread societal impacts over Europe due to a severe cold spell and extraordinary rainy and windy conditions. We find that the impact of this SSW event on the surface was regulated by two low-pressure systems that developed over the North Atlantic. Even though the SSW event was well developed, alternative behavior of these systems could have led to drastically different weather conditions over Europe. Thus, this study highlights the role of the tropospheric circulation in the effectiveness of the stratospheric impact on surface weather.

Notes

Acknowledgments JJGA is funded through FJC2018-035821-I and PID2019-107125RB-I00 by the Spanish State Agency of Research, co-funded by the European Social Fund. CMG is funded by the Helmholtz Association (SPREADOUT; grant VH-NG-1243). Support from the Swiss National Science Foundation (PP00P2_170523) to DD is gratefully acknowledged. IG and BRF are supported by the EU H2020 project NextGEMS (No. 101003470) and the Spanish Ministry of Economy and Competitiveness project PRE4CAST (CGL2017-86415-R). PZ is supported by grant PID2019- 109107GB-I00 and BA is supported through the JeDiS (RTI2018-096402- B-I00) project both funded by the Spanish Ministry of Science, Innovation and Universities. We would like to thank the two anonymous reviewers for their careful corrections and constructive suggestions during the review process.

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Geophysical Research Letters - 2021 - Gonz lez‐Alem n.pdf

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Additional details

Funding

European Commission
NextGEMS - Next Generation Earth Modelling Systems 101003470