HR: 14:20h
AN: H23F-03    [Abstracts]
TI: Propagation of hydro-climatic fluctuations to soil moisture dynamics
AU: * Porporato, A M
EM: amilcare@duke.edu
AF: Duke University, 127 Hudson Hall, Durham, NC 27708 United States
AU: Daly, E
EM: edoardo.daly@polito.it
AF: Politecnico di Torino, Corso Duca degli Abruzzi, 24, Torino, 10129 Italy
AB: Using field observation and analytical considerations, we investigate the propagation of temporal fluctuation in rainfall and potential evapotranspiration to the dynamics of soil moisture. In particular, we study a stochastic model of soil moisture with a marked Poisson process for rainfall, soil moisture-dependent infiltration, and Gaussian fluctuations in potential evapotraspiration. We derive and solve the equations for the probability distribution, mean, and variance of the fluctuations to elucidate the dynamic effect of external forcing on soil water balance. It is shown how hydroclimatic fluctuations are distorted and modified by the nonlinear soil moisture dynamics and how rainfall fluctuations are dominating soil moisture dynamics except when close to saturation, while evapo-transpiration fluctuations, being continuously modulated by soil moisture, tend to be relevant only for very shallow soils.
DE: 1818 Evapotranspiration
DE: 1836 Hydrologic budget (1655)
DE: 1854 Precipitation (3354)
DE: 1866 Soil moisture
DE: 1869 Stochastic processes
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting