AN IMPROVED APPROACH TO FIRE MONITORING IN WEST-AFRICA USING AVHRR DATA

Data from the Advanced Very High Resolution Radiometer (AVHRR) have been used for the detection of fires in various ecosystems throughout the world. In this study the most commonly used methods have been applied to a time-series of 63 AVHRR day time images for the whole of West Africa for the 1991-1992 dry season. The West African region includes ecosystems ranging from dry Sahelian grasslands to moist tropical forests. Furthermore, these ecosystems show considerable seasonal variability. Existing methods were found to be inadequate for fire detection for the whole region because of the spatial and temporal heterogeneity of the region's environments. A number of changes were made to the established methods and the new fire detection procedure was applied to the time-series. Field verification and interpretation of the results in the context of the main ecological divisions of the region showed the new method to give good results for all ecosystems throughout the season. Finally, interpretation of fire counts using a Geographical Information System illustrates how such data can improve our knowledge of fire activity at national and sub-continental scales.