HR: 09:15h
AN: H31J-06 INVITED     [Abstracts]
TI: Revisiting multifractality of high resolution temporal rainfall using a wavelet-based formalism
AU: * Foufoula-Georgiou, E
EM: efi@umn.edu
AF: St. Anthony Falls Lab, University of Minnesota 2 3rd Avenue SE, Minneapolis, MN 55414 United States
AU: Venugopal, V
EM: venu@msi.umn.edu
AF: St. Anthony Falls Lab, University of Minnesota 2 3rd Avenue SE, Minneapolis, MN 55414 United States
AU: Roux, S G
EM: sroux@ens-lyon.fr
AF: Laboratoire de Physique, Ecole Normale Superieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cédex 07, France., Lyon, 69364 France
AU: Arneodo, A
EM: alain.arneodo@ens-lyon.fr
AF: Laboratoire de Physique, Ecole Normale Superieure de Lyon, 46 Allée d'Italie, 69364 Lyon Cédex 07, France., Lyon, 69364 France
AB: We re-examine the scaling structure of temporal rainfall using wavelet-based methodologies which offer important advantages compared to the more traditional multifractal approaches such as box counting and structure function techniques. In particular, we explore two methods based on the Continuous Wavelet Transform (CWT) and the Wavelet Transform Modulus Maxima (WTMM): the partition function method and the newer and more efficient magnitude cumulant analysis method. We also explore a two-point magnitude correlation analysis which is able to infer the presence or absence of multiplicativity as the underlying mechanism of scaling. The diagnostic power of these methodologies for small samples, signals with short ranges of scaling, and signals for which high frequency fluctuations are superimposed on a low-frequency component (all common attributes of geophysical signals) is carefully documented. Application of these methodologies to several midwestern convective storms sampled every 5 seconds over several hours provide new insights. They reveal the presence of a very intermittent multifractal structure (a wide spectrum of singularities) in rainfall fluctuations between the scales of 5 minutes and the storm pulse duration of 1-2 hours. The two-point magnitude statistical analysis suggests that this structure is associated with a local multiplicative cascading mechanism which applies only within storm pulses but not over the whole storm duration.
DE: 1854 Precipitation (3354)
DE: 3280 Wavelet transform (3255, 4455)
DE: 4440 Fractals and multifractals
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
SC: Hydrology [H]
MN: Fall Meeting 2005