Sciences Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations

Abstract. The probabilistic description of soil moisture dy-namics is a relatively new topic in hydrology. The most com-mon ecohydrological models start from a stochastic differ-ential equation describing the soil water balance, where the unknown quantity, the soil moisture, depends both on spaces and time. Most of the solutions existing in literature are ob-tained in a probabilistic framework and under steady-state condition; even if this last condition allows the analytical handling of the problem, it has considerably simplified the same problem by subtracting generalities from it. The steady-state hypothesis, appears perfectly applicable in arid and semiarid climatic areas like those of African’s or middle American’s savannas, but it seems to be no more valid in areas with Mediterranean climate, where, notoriously, the wet season foregoes the growing season, recharging wate