Journal article
How bad is the rain? Applying the extreme rain multiplier globally and for climate monitoring activities
Meteorological applications, Vol.32(2), e70031
03/2025
DOI: 10.1002/met.70031
Abstract
A typical question posed following an extreme precipitation event is: How does this compare to past events? This question is being asked more frequently and is of importance to climate monitoring services, such as the Copernicus Climate Change Service (C3S). Currently, the statistics extensively used for this purpose are not generally understandable to the wider public, or they are not tailored towards presenting extremes. To mitigate this situation, this article uses a modified version of the Extreme Rain Multiplier (ERM), which was developed for tropical cyclones, and applies it to precipitation events globally. For daily precipitation considered herein, the ERM is calculated by dividing the daily precipitation accumulation during an event by the mean historical annual maxima of daily precipitation (RX1day), which is computed over 1991–2020. Using the European Centre for Medium‐Range Weather Forecasts ERA5 reanalysis, the calculation of the ERM is illustrated for six extreme events around the world; these included convective systems, atmospheric rivers and tropical cyclones. A maximum ERM of 4 was found during Storm Daniel, in Greece, and in Tropical Cyclone Jasper in Australia, implying that four times the mean RX1day precipitation occurred. The ERM will be useful in C3S reporting activities because it can objectively identify extreme precipitation events. Furthermore, after extracting the number of precipitation events per year at each grid point that had an ERM exceeding 1, a trend analysis was undertaken to ascertain if the frequency of extreme events had changed with time. Results showed that the most widespread increasing trends in the ERM were in the tropics, but these trends are thought to be questionable in ERA5. There were few clear trends in other regions. In conclusion, the ERM can communicate the level of extreme precipitation in a clear manner and can be used in climate monitoring activities.
Details
- Title: Subtitle
- How bad is the rain? Applying the extreme rain multiplier globally and for climate monitoring activities
- Creators
- David A. Lavers - University of BirminghamGabriele Villarini - Princeton UniversityHannah L. Cloke - University of ReadingAdrian Simmons - European Centre for Medium‐Range Weather Forecasts (ECMWF) Reading UKNigel Roberts - European Centre for Medium‐Range Weather Forecasts (ECMWF) Reading UKAnna Lombardi - European Centre for Medium‐Range Weather Forecasts (ECMWF) Reading UKSamantha N. Burgess - European Centre for Medium‐Range Weather Forecasts (ECMWF) Reading UKFlorian Pappenberger - European Centre for Medium‐Range Weather Forecasts (ECMWF) Reading UK
- Resource Type
- Journal article
- Publication Details
- Meteorological applications, Vol.32(2), e70031
- DOI
- 10.1002/met.70031
- ISSN
- 1350-4827
- eISSN
- 1469-8080
- Publisher
- WILEY
- Grant note
- Natural Environment Research Council: NE/S015590/1 UKRI Natural Environment Research Council (NERC)
The production of ERA5 and the contributions of David Lavers, Adrian Simmons, Anna Lombardi, and Samantha Burgess were supported by the Copernicus Climate Change Service, which is implemented by ECMWF on behalf of the European Union. Hannah Cloke acknowledges funding from the UKRI Natural Environment Research Council (NERC) The Evolution of Global Flood Risk (EVOFLOOD) project Grant NE/S015590/1. We are grateful to the comments of the Editor and three anonymous reviewers whose comments helped to improve this paper.
- Language
- English
- Date published
- 03/2025
- Academic Unit
- Civil and Environmental Engineering; IIHR--Hydroscience and Engineering
- Record Identifier
- 9984811208702771
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