Global Fire Calendar Probability maps from the Analysis of Global Burned Surfaces Time Series (1982-1999)

Regular monitoring of global burnt surface areas has been identified as an essential climate variable by the Global Climate Observing System (GCOS, 2003) because vegetation fires are important drivers of climate, indicators of possible climate change and have a role to play in climate change adaptation and mitigation strategies. The GCOS’s requirements include the need to identify areas around the globe affected by fire, monitoring the occurrence/seasonality of fire activity and inter-annual variability as well as estimating the spatial distribution of burnt surfaces. Accurate descriptions of changes in fire seasonality, frequency, intensity, severity, size, rotation period and changes in fire return interval are also needed for ecological studies (Payette, 1992) because these factors have a strong influence on plant species composition. Daily global observations from the Advanced Very High Resolution Radiometers (AVHRR) on the series of meteorological satellites operated by the National Oceanic and Atmospheric Administration (NOAA) between 1982 and 1999 were used to generate a new weekly global burnt surface (GBS) product at a resolution of 8km. Comparison with independently available information on fire locations and timing suggest that whilst the time-series cannot yet be used to make accuracy and quantitative estimates of global burnt area, it does provide a reliable estimate of changes in location and season of burning on the global scale. GBS 1982-1993 time-series was developed and used to characterize fire activity in both northern and southern hemispheres on the basis of average seasonal cycle and inter-annual variability (Carmona-Moreno et al., 2003). An extension of this time series (GBS 1982-1999) was combined to provide gridded maps documenting the probability of fire occurring in any given season for any location. The interannual variations in the extension and probability of the fire in different regions of the world are closed linked with El Niño Southern Oscillation (ENSO) at regional but also at global scales (CamonaMoreno et al., 2005.a-b) and, therefore, with regional climate conditions which has direct implications on the state of the biomass including fuel amount and fuel moisture content (Lyon, 2004; and, Camberlin et al., 2001). This paper deals with the global fire seasonality and fire distribution during the period 1982-1999. Some regions of the globe appear very stables during this period as this is the case at high and medium latitudes in the Northern Hemisphere (June-July-August), Far East of China-Russia (March-April-June), Central Africa (June-July-August), and African savannas (December-January-February and September-October-November). In other regions, even if there is always a maximum of occurrence probability in a given trimester, this is more seasonal distributed. These can be considered as fire prone areas-ecosystems driven by and/or more sensitive to climate variability: Southern Europe, Southern and East Africa, Australia, East Asia, Central and Northern Latin America... These data should find use for initiating and/or validating the output from dynamic vegetation models, trace gas emission models and general circulation models.