EGU25-19805, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-19805
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Spatial Coincidence of Extreme Wind Across European Cities: Evidence from 10,000 Years of Expired ECMWF Forecasts
Petr Dolezal and Emily Shuckburgh
Petr Dolezal and Emily Shuckburgh
  • University of Cambridge, AI for the research of Environmental Risk (AI4ER), Department of Computer Science and Technology, Cambridge, United Kingdom of Great Britain – England, Scotland, Wales (pd423@cam.ac.uk)

We present a novel method to construct a 10,000-year event set for European weather using expired ensemble forecasts from ECMWF [1]—requiring no additional computational effort. Derived from the same numerical model underlying ERA5, this approach naturally extends it more than two orders of magnitude, whilst inherently overrepresenting the climates of the 2010s and 2020s. Hence, it provides a valuable resource for quantifying risks in today’s already-warmed climate

Our evaluation focuses on extreme wind speeds from extra-tropical cyclones impacting major European cities. With a rigorous order statistics framework, we confirm that this dataset replicates the statistical tails of ERA5 for return periods up to RP40 and extends exceedance probability (EP) curves up to RP10,000. Crucially, its physical consistency enables robust analysis of joint distributions across space and time, offering precise insights into compound and correlated risks. Using empirical copulas, we quantify critical conditional probabilities, such as P(Paris = RP100 London = RP50), a task infeasible with only the weather record beyond RP5.

This method leverages years of historical computational investments by ECMWF, that created a vast global low-bias source of simulated weather data, fully interchangeable with ERA5 for seamless integration into existing pipelines. Following two years of archive extraction efforts, we compiled a subset of surface variables (t2m, 10m/100m wind, runoff,...) and make it widely available to the community [2]. 

[1] European Centre for Medium-Range Weather Forecasts (ECMWF) __Atmospheric Model Ensemble extended forecast__ https://www.ecmwf.int/en/forecasts/datasets/set-vi
[2] Dolezal P., Expired ECMWF ENSemble Extended forecasts and Reforcasts for Renewable power in Europe. NERC EDS Centre for Environmental Data Analysis,
https://catalogue.ceda.ac.uk/uuid/7783f79c7080456088d98a34ca238bfa

How to cite: Dolezal, P. and Shuckburgh, E.: Spatial Coincidence of Extreme Wind Across European Cities: Evidence from 10,000 Years of Expired ECMWF Forecasts, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19805, https://doi.org/10.5194/egusphere-egu25-19805, 2025.