Combining NDVI and surface temperature for the estimation of live fuel moisture content in forest fire danger rating

This paper presents an empirical method for deriving fuel moisture content (FMC) for Mediterranean grasslands and shrub species based on multitemporal analysis of NOAA–AVHRR data. The results are based on 6 years of field measurements of FMC. The empirical function was derived from a 4-year series and includes multitemporal composites of AVHRRʹs normalized difference vegetation index (NDVI) and surface temperature (ST) values, as well as a function of the day of the year. It was tested using data from 2 other years on the same site as well as other sites with similar species but very distant from each other and with different elevation ranges. The results show that the model provides a consistent estimation of FMC, with high accuracies for all study sites and species considered, with r^2 values over 0.8 for both grasslands and shrub species. This performance enables the model to be used to derive spatial estimator of FMC, which is a key factor in operational fire danger management in Mediterranean conditions.