New perspectives on African biomass burning dynamics

Abstract

Biomass burning is a key Earth system process and, in particular a major element of the terrestrial carbon cycle and a globally significant source of atmospheric trace gases and aerosols. Smoke emitted during combustion affects air quality, atmospheric chemical composition, and Earths radiation budget [Le Canut et al., 1996]. In terms of carbon emissions, vegetation fires are, globally and on average, believed to generate emissions equivalent to between perhaps one third and one half of those from fossil fuel combustion, and savanna fires are responsible for around 50% of the global vegetation fire carbon release [Williams et al., 2007].At the continental scale, Africa is, on average, the single largest source of biomass burning emissions, responsible for 30–50% of total global annual fuel combustion [Andreae, 1991; van der Werf et al., 2006]. African burning is characterized by two distinct burning seasons: primarily between October and March in the Northern Hemisphere and between June and November in the Southern Hemisphere [Giglio et al., 2006]. In Africa, the vast majority of fires result from anthropogenic burning, associated, for example, with farming and livestock practices. This pattern of human‐initiated ignitions, together with the daily meteorological dynamics of wind and relative humidity, contribute to a strong diurnal variability in the number and extent of fires [Edwards et al., 2006].