Modelling hourly variability in Eucalyptus globulus litter moisture content

Abstract

Fuel moisture content is a basic parameter of the present fire danger rating systems and fire behaviour simulation programs. Diurnal Eucalyptus globulus litter fuel moisture content variation patterns in rain free periods are shown in this document. Several situations in relation to sun exposition, wind and nocturnal dead organic fuels dew are considered and the capacity of prediction models which are available in literature in order to follows the patterns is evaluated. It is concluded by emphasizing the good behaviour of a physically based model in the different conditions considered and the appropriate behaviour of particular empirical models to specific situations. Fuel moisture nocturnal latent heat effect is remarked together with the fast sun effect drying up litter which make possible to pass, in a very short time step, from a non inflammable fuel to a situation clearly well-disposed to fire propagation.