Using MODIS to evaluate heterogeneity of biomass burning in southern African savannahs:: a case study in Etosha

As part of SAFARI 2000, this study investigated fire severity associated with, and emissions released from, a wildfire that burned a total area of approximately 3200 km(2) of semi-arid savannahs in the region of Etosha National Park, Namibia. Percent tree cover derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data was used to scale up from site- level field measurements to landscape-level emission fields. Empirical relationships relating fuel load and combustion completeness to tree cover were developed from field observations. These relationships were coupled to the remotely sensed data to determine the emissions released over the entire area burned. Emissions from this single fire event were estimated to be 1.4 x 10(12) g of CO2, 52.4 x 10(9) g of CO, 1.5 x 10(9) g of CH4, 1.85 x 10(9) g of non- methane hydrocarbons (NMHC), and 2.4 x 10(9) g of particles less than 2.5 mu m (PM2.5). A Normalized Burned Index difference (NBIdiff), representative of fire severity and modified for MODIS data was used to assess the heterogeneity of the burned areas, but no significant correlation was found between this NBIdiff and combustion completeness (CC).