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An assessment of extra-tropical cyclone precipitation extremes over the Southern Hemisphere using ERA5
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  • Cameron McErlich,
  • Adrian J. McDonald,
  • James Arthur Renwick,
  • Alex J Schuddeboom
Cameron McErlich
University of Canterbury

Corresponding Author:cameron.mcerlich@pg.canterbury.ac.nz

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Adrian J. McDonald
University of Canterbury
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James Arthur Renwick
Victoria University of Wellington
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Alex J Schuddeboom
University of Canterbury
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ERA5 reanalysis is used to examine extreme precipitation using a spatially dependent precipitation threshold applied within a cyclone compositing framework. This is used to account for regional variation in precipitation generating processes within Southern Hemisphere mid-latitude cyclones across the cyclone lifecycle. The spatial extent of extreme precipitation is limited to a smaller region around the cyclone centre compared to non-extreme precipitation, though extreme precipitation displays a good spatial correlation with non-extreme precipitation. Extreme precipitation occurs more often during the deepening phase of the cyclone before it reaches a maximum depth. Precipitation occurrence at the 90th and 98th percentiles reduces to 46% and 30% of the deepening value across the cyclone lifecycle, averaged over the composite. Precipitation fraction at the 90th and 98th percentile reduces to 80% and 60% of the deepening value. Our methodology provides a quantitative assessment of precipitation extremes both spatially and temporally, within a cyclone compositing framework.
18 Apr 2023Submitted to ESS Open Archive
29 Apr 2023Published in ESS Open Archive