%0 Conference Proceedings %T Impact of small scale rainfall uncertainty on urban discharge forecasts %+ Laboratoire Eau, Environnement et Systèmes Urbains (LEESU) %+ Centre de recherche sur la dynamique du système Terre (GEOTOP) %+ Department of Civil and Environmental Engineering [Imperial College London] %+ Department of Civil Engineering %A Gires, Auguste %A Schertzer, D %A Tchiguirinskaia, Ioulia %A Lovejoy, S. %A Maksimovic, Cedo %A Onof, Christian %A Simoes, Nuno %< avec comité de lecture %B Weather radar and hydrology %C Exeter, United Kingdom %P 100 %8 2011-04-18 %D 2011 %K multifractals %K rainfall downscaling %K urban hydrology %K power law %K RainGain %Z Environmental Sciences %Z Sciences of the Universe [physics]/Earth Sciences/HydrologyConference papers %X We use a multifractal characterization of two heavy rainfall events in the London area to quantify the uncertainty associated to the rainfall variability at scales smaller than the usual C-band radar resolution (1 km2 x 5 min.) and how its transfer to sewer discharge forecasts. The radar data are downscaled to a higher resolution with the help of a multifractal cascade whose exponent values correspond to the estimates obtained from the radar data. A hundred of downscaled realizations are thus obtained and input into a semi-distributed urban hydrological model. Both probability distributions of the extremes are shown to follow a power-law, which corresponds to a rather high dispersion of the results, therefore to a large uncertainty. We also discuss the relationship between the respective exponents. In conclusion, we emphasize the corresponding gain obtained by higher resolution radar data. %G English %L hal-00677435 %U https://enpc.hal.science/hal-00677435 %~ SDE %~ AGROPARISTECH %~ ENPC %~ UNIV-MLV %~ PARISTECH %~ ENPC-LEESU %~ GIP-BE %~ UPEC %~ HMCO %~ AGREENIUM %~ UNIV-EIFFEL %~ UPEM-UNIVEIFFEL