EGU22-1669, updated on 20 Jul 2024
https://doi.org/10.5194/egusphere-egu22-1669
EGU General Assembly 2022
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evaluation and Bias Correction of Simulated Sub-daily Rainfall Extremes by Regional Climate Models

Hans Van de Vyver1, Bert Van Schaeybroeck1, Rozemien De Troch1, Lesley De Cruz1,9, Rafiq Hamdi1, Cecille Villanueva-Birriel2,3, Philippe Marbaix3, Jean-Pascal van Ypersele3, Hendrik Wouters4,8, Sam Vanden Broucke4, Nicole van Lipzig4, Sébastien Doutreloup5, Coraline Wyard5,6, Chloé Scholzen5,7, Xavier Fettweis5, Steven Caluwaerts1,8, and Piet Termonia1,8
Hans Van de Vyver et al.
  • 1Royal Meteorological Institute of Belgium, Brussels, Belgium
  • 2NOAA/National Weather Service, San Juan, Puerto Rico
  • 3Université Catholique de Louvain, Louvain-la-Neuve, Belgium
  • 4Katholieke Universiteit Leuven, Leuven, Belgium
  • 5Université de Liège, Liège, Belgium
  • 6Institut Scientifique de Service Public, Liège, Belgium
  • 7University of Oslo, Oslo, Norway
  • 8Universiteit Gent, Gent, Belgium
  • 9Vrije Universiteit Brussel, Brussel, Belgium

Sub-daily precipitation extremes can have a huge impact on society as they cause hazards such as flooding, erosion and landslides. For example, the July floods in Germany, Belgium and nearby countries, were one of the costliest events in Europe, with insured losses up to USD 13 billion. Climate change is expected to intensify precipitation extremes as atmospheric water content increases by 6-7% per degree of warming, underscoring the need to predict  future hydrological hazards. Regional Climate Models (RCMs) typically run at a spatial resolution of 12-25 km, but they insufficiently describe the small-scale features of observed sub-daily precipitation extremes. The past decade, convection-permitting RCMs were developed which run at high resolution (1-4 km), and explicitly resolve deep convection. Confidence in future projections requires that RCMs adequately simulate the statistical features of observed sub-daily extreme precipitation and  also represent the physical processes associated with convective events. We propose a diagnostic framework for simulated 1h-24h rainfall extremes that summarizes the overall RCM performance. This includes the following metrics: the seasonal/diurnal cycle, temperature and humidity dependency, temporal scaling, and spatiotemporal clustering. A substantial part of the work is devoted to the statistical modelling of the metrics with Extreme Value Theory (EVT). We illustrate the evaluation tool with convection-permitting RCM simulations over Belgium against high-frequency observations and assess the benefit of the convection-permitting RCMs with respect to coarser scales. Finally, we give some guidelines for bias correction of simulated precipitation extremes.

How to cite: Van de Vyver, H., Van Schaeybroeck, B., De Troch, R., De Cruz, L., Hamdi, R., Villanueva-Birriel, C., Marbaix, P., van Ypersele, J.-P., Wouters, H., Vanden Broucke, S., van Lipzig, N., Doutreloup, S., Wyard, C., Scholzen, C., Fettweis, X., Caluwaerts, S., and Termonia, P.: Evaluation and Bias Correction of Simulated Sub-daily Rainfall Extremes by Regional Climate Models, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1669, https://doi.org/10.5194/egusphere-egu22-1669, 2022.