Global fire activity from two years of MODIS data

Abstract

Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA Earth Observing System Terra and Aqua satellites provides global fire observations of unprecedented quality. This paper presents spatial and temporal distributions of active fires from 2001 and 2002, the first 2 years of the MODIS active fire data record. Monthly fire counts were analysed globally and within several regions of major fire activity and vegetation type. The global maximum of the annual cycle of fire activity for both years occurred in August; a combined result of burning during the dry season in the Southern Hemisphere tropics and the warm season over the Northern Hemisphere extratropics. The minimum of global fire activity occurred in March in both years. Burning in the tropics occurred mostly in savanna and shrubland areas with a high percentage of herbaceous vegetation. In the extratropics, fires were detected over croplands, grasslands and forests. The global total numbers of fire counts observed in 2001 and 2002 differed by less than 3%, but regionally significant differences were found between the two years in total and relative fire counts and in the timing of burning. Fire counts from daytime MODIS observations from Terra and Aqua also provided evidence of the diurnal cycle of fire activity. This analysis of ‘fire/no fire’ binary indicators is a first-order approximation of global spatio-temporal fire dynamics. For several applications, such as the estimation of pyrogenic emissions, further studies of burned area and fire characteristics are needed.