Global sensitivity analysis and scale effects of a fire propagation model used over Mediterranean shrublands

A Global Sensitivity Analysis (GSA) and an analysis of scale effects have b een carried out over the equations given by Rothermel (1972), with some add itional modifications. Data mainly derived from Mediterranean shrublands an d a spatially close meteorological station have been used to derive probabi lity distribution functions for the variables involved. In spite of the abu ndant non-linearities contained in the equations studied, scale effects fou nd have been relatively unimportant, thus supporting the current usage of s patial averages (i.e. fuel models) in spatially distributed models based on the Rothermel equations. On the other hand, the results of the GSA clearly showed the negligible effect of the variability of three of the model vari ables (the low heat content, the particle density and the mineral content) on the output values. However, all other input variables had some noticeabl e effect over the variability of the output, and they cannot be ignored if an optimal use of the model is desired. Finally, caution is recommended if results have to be extrapolated to other types of vegetation or climate. (C ) 2001 Elsevier Science B.V. All rights reserved.