How important are post-tropical cyclones for European windstorm risk?

Post-tropical cyclones (PTCs) extend many hazards associated with tropical cyclones (TCs) to the mid-latitudes. Despite recent high-impact cases affecting Europe such as Ophelia, little research has been done to characterize the risk of PTCs. Here we compare the climatologies and intensity distribut...

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Bibliographic Details
Main Authors: Sainsbury, Elliott M., Schiemann, Reinhard K. H., Hodges, Kevin I., Shaffrey, Len C., Baker, Alex J., Bhatia, Kieran T.
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2020
Subjects:
Online Access:https://centaur.reading.ac.uk/92869/
https://centaur.reading.ac.uk/92869/9/2020GL089853.pdf
Description
Summary:Post-tropical cyclones (PTCs) extend many hazards associated with tropical cyclones (TCs) to the mid-latitudes. Despite recent high-impact cases affecting Europe such as Ophelia, little research has been done to characterize the risk of PTCs. Here we compare the climatologies and intensity distributions of mid-latitude cyclones (MLCs) and PTCs in the North Atlantic and Europe by tracking cyclones in the ERA5 reanalysis. Considering hurricane-season cyclones impacting Northern Europe, PTCs show a significantly higher mean maximum intensity than MLCs, but make only a small contribution to total windstorm risk. Our results show that a disproportionately large fraction of high-intensity cyclones impacting Europe during hurricane season are PTCs. The fraction of PTCs impacting N Europe with storm-force (>25ms-1) winds is approximately ten times higher than for MLCs. Less than 1% of cyclones impacting Northern Europe are identified to be PTCs. This rises to 8.8% when considering cyclones which impact with storm-force winds.