Effects of climate variability on Savannah fire regimes in West Africa

Bushfires are recognized as environmental processes that affect the atmosphere by the gases and particles emitted and have an ecological and climatic impact. However, there are still numerous uncertainties, particularly about the variability of fire occurrence on the intra- and inter-annual scale. Our objective was to distinguish the space-time variability of fires in West Africa through analysis of burned areas using SPOT VEGETATION from L3JRC (1 April 2000 to 31 March 2007) which were obtained from the modification in the algorithm of cells from the GBA 2000 project. We also analyzed the influence of several large scale factors such as the ENSO, SOI, NAO and the north-south Atlantic temperature gradient factor (SSTG) on the variability of the span of burned areas. Based on areas burned monthly, we calculated the frequency of fire passage on the same pixel. This helped characterize the activity of pixels and distinguish the most vulnerable zones (with a lot of fire activity) from the least vulnerable ones (with less activity). Using a correlation calculation, we also found the influence of the quality of precipitations during preceding rainy seasons on burned areas during the dry season along with climate factors such as MEI, SOI, NAO and the SSTG.