Remote sensing of burned areas in tropical savannas

Problematic aspects of fire in tropical savannas are reviewed, from the standpoint of their impact on the detection and mapping of burned areas using remotely sensed data. Those aspects include: the heterogeneity of savanna - resulting in heterogeneity of fire-induced spectral changes; fine fuels and low fuel loadings-resulting in short persistence of the char residue signal; tropical cloudiness - which makes multitemporal image compositing important; the frequent presence of extensive smoke aerosol layers during the fire season - which may obscure fire signals; and the potential problem of detecting burns in the understory of woody savannas with widely variable tree stand density, canopy cover and leaf area index. Finally, the capabilities and limitations of major satellite remote sensing systems for pan-tropical burned area mapping are addressed, considering the spatial, spectral, temporal and radiometric characteristics of the instruments.