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

Data from the Advanced Very High Resolution Radiometer (AVHRR) have be en used for the detection of fires in various ecosystems throughout th e world. In this study the most commonly used methods have been applie d to a time-series of 63 AVHRR day time images for the whole of West A frica for the 1991-1992 dry season. The West African region includes e cosystems ranging from dry Sahelian grasslands to moist tropical fores ts. Furthermore, these ecosystems show considerable seasonal variabili ty. Existing methods were found to be inadequate for fire detection fo r the whole region because of the spatial and temporal heterogeneity o f the region's environments. A number of changes were made to the esta blished methods and the new fire detection procedure was applied to th e 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 sea son. Finally, interpretation of fire counts using a Geographical Infor mation System illustrates how such data can improve our knowledge of f ire activity at national and sub-continental scales.