Improving burning efficiency estimates through satellite assessment of fuel moisture content

Abstract

[1] The assessment of burning efficiency (BE) is a critical parameter for estimating gas emissions derived from biomass burning. Several authors have proven a strong dependence of BE on moisture conditions of the fuel. This paper presents an empirical study where the relationships between fuel moisture content (FMC) and satellite-derived variables are evidenced. The study was conducted in Mediterranean ecosystems, using both high-and low-resolution satellite images (Landsat-TM, SPOT-Vegetation and NOAA-advanced very high resolution radiometer). First, theoretical relationships between FMC and reflected or emitted radiance are discussed. Second, multitemporal trends of vegetation indices and surface temperatures are compared with field measurements of FMC for Mediterranean grasslands and shrublands. Pearson r correlation coefficients were computed for a 4-year series of field measurements of FMC and satellite images.Pearson r values show a good correlation between FMC and shortwave infrared (SWIR; 1.6-2 mm) reflectance, for both grasslands and shrublands, although the relations improve when near-infrared (NIR) and SWIR reflectances are combined. ''Traditional'' spectral vegetation indices (based on the red and NIR reflectances) only work reasonably well with grasslands but not with shrublands. For shrublands a synthetic index mixing vegetation indices and surface temperature improves determination coefficients to estimate FMC. Finally, on the basis of these findings, multivariate fittings were computed and validated using AVHRR images. The assessment sample also provided high determination coefficients (r 2 > 0.75) in estimating FMC, both for the study site and other control sites.

Estimation of Herbaceous Fuel Moisture Content Using Vegetation Indices and Land Surface Temperature from MODIS Data

“…EWT is difficult to operationally measure in the field, because it requires the calculation of leaf area [51]. Herbaceous leaf area (A) was measured visually in the field.…”

“…The average of the four samples constituted the sample weight of fresh biomass in the plot and was disposed in a hessian bag before being oven-dried at 60 °C until constant dry weight was obtained [46,47]. The direct method for the estimation of the herbaceous water content was made on the basis of two different metrics: (i) the fuel moisture content [4,5,8,29,48] and (ii) the equivalent water thickness at leaf level [25,[27][28][29][30][31][49][50][51]. FMC (Equation (1) [5,11,52]) is defined as the percentage of moisture content as compared to dry material weight as follows:…”

Fuel moisture sampling and modeling in Pinus elliottii Engelm. plantations based on weather conditions in Paraná - Brazil

“…Satellite remote sensing has also emerged as an advanced technique to provide frequent and high-resolution measurements of forest fuel types and wildfire properties. Recently, great efforts have been made to develop algorithms to estimate fuel moisture using this technology (Chuvieco et al 2004, De la Riva et al 2005, Aguado et al 2007, Wang & Qu 2007.The goal of the present work was to test methods, based on meteorological variables, to determine fuel moisture by calculating the degree of correlation between meteorological elements and fuel moisture and by testing the mathematical models describing such relationships. The Experimental Station is an area of approximately 120 ha, created in 1962 to support teaching and research activities carried out at the National School of Forestry.…”

Quality assessment of the fire hazard forecast based on a fire potential index for the Mediterranean area by using a MSG/SEVIRI based fire detection system

“…In this direction moves the attempt to estimate vegetation water content by using satellite. This can be accomplished by introducing a new vegetation index (GVMI, Global Vegetation Moisture Index) [16] or by using an index like the FMC (Fuel Moisture Index) [17]. …”