Orographic Effect on Extreme Precipitation Statistics Peaks at Hourly Time Scales

Francesco Marra*, Moshe Armon, Marco Borga, Efrat Morin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Orographic impact on extreme subdaily precipitation is critical for risk management but remains insufficiently understood due to complicated atmosphere-orography interactions and large uncertainties. We investigate the problem adopting a framework able to reduce uncertainties and isolate the systematic interaction of Mediterranean cyclones with a regular orographic barrier. The average decrease with elevation reported for hourly extremes is found enhanced at subhourly durations. Tail heaviness of 10-min intensities is negligibly affected by orography, suggesting self-similarity of the distributions at the convective scale. Orography decreases the tail heaviness at longer durations, with a maximum impact around hourly scales. These observations are explained by an orographically induced redistribution of precipitation toward stratiform-like processes, and by the succession of convective cores in multihour extremes. Our results imply a breaking of scale-invariance at subhourly durations, with important implications for natural hazards management in mountainous areas.

Original languageAmerican English
Article numbere2020GL091498
JournalGeophysical Research Letters
Issue number5
StatePublished - 16 Mar 2021

Bibliographical note

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  • extreme precipitation
  • mountainous areas
  • orography
  • right tail
  • risk management
  • subhourly precipitation


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