HR: 12:05h
AN: H32C-08    [Abstracts]
TI: Non-power-law scale properties of rainfall: consequences for downscaling and stochastic rainfall generation
AU: Zanetti, S
EM: mariozanetti@libero.it
AF: International Center for Hydrology 'D. Tonini' Univeristy of Padova University of Padova, via Loredan 20, Padova, I-35131
AU: Alvaro, A
EM: nali_io@hotmail.com
AF: International Center for Hydrology 'D. Tonini' Univeristy of Padova University of Padova, via Loredan 20, Padova, I-35131
AU: * Marani, M
EM: marco.marani@unipd.it
AF: International Center for Hydrology 'D. Tonini' Univeristy of Padova University of Padova, via Loredan 20, Padova, I-35131
AB: The identification of general relationships linking statistical properties of rainfall aggregated at different temporal and spatial scales possesses clear theoretical and practical relevance. Among other properties it is important to characterize the scale dependence of rainfall variability, which may, for many purposes, be summarized by its variance. This contribution presents theoretical results and observational analyses connecting the variance of temporal and spatial rainfall to the scale of observation under the assumption of second-order stationarity. In particular we show that the theoretically-derived form of the variance as a function of scale is incompatible with power-law relations usually assumed for the second-order statistical moment within multiscaling approaches to rainfall modelling. We validate the predictions of the theoretical derivations making use of a dataset representing a wide variety of resolutions (from 2 s to 1 hour in time and 4 km in space), climates and observation instruments. We then apply these theoretical and observational results to stochastically downscale daily rainfall observations to the hourly scale. Results are statistically compared to hourly validation observations and optimal downscaling methodologies are identified.
DE: 1839 Hydrologic scaling
DE: 1854 Precipitation (3354)
DE: 1869 Stochastic hydrology
SC: Hydrology [H]
MN: Fall Meeting 2005