P. R. Dowty

Satellite remote sensing of fires during the SAFARI campaign using NOAA Advanced Very High Resolution Radiometer data

Active fires in southern Africa were detected using daily NOAA advanced very high resolution radiometer (AVHRR) 1-km satellite data. The active fire distribution during the period of the SAFARI intensive field campaign in September and October 1992 is described. The distribution of fires for the period of the campaign is presented along with a comparison for the same period in 1989. For the latitudinal belt between 15° and 30°S which was affected by drought in 1992, there was an average of 49% fewer fires in 1992 than in 1989. However, most of the burning in southern Africa takes place between 5° and 20°S with peak activity between the months of July and September. The interannual variability in the amount and timing of fires was noted. The relationship between fires, rainfall, and vegetation state for the two years are described for sample locations. The extent of the 1992 drought and its impact on the occurrence of fire are also discussed.

Regional fuel load for two climatically contrasting years in southern Africa

[1] Available fuel loads for burning in savanna ecosystems in the southern African region have been estimated using a new Fuel load-Net Primary Production model based on ecophysiological processes such as respiration and Potential Evapotranspiration. The model outputs 15-day standing available fuel load layers for an entire year (a total of 24 layers). Published data from the Southern African Fire-Atmosphere Research Initiative (SAFARI-92) project and from the Southern African Regional Science Initiative (SAFARI 2000) field campaigns were generally in agreement with the estimations. Consistently with previous studies, precipitation was recognized to be the major climatic driver for fuel production. As a consequence, even though there was a regional increase in precipitation in 1999–2000 as compared to the 1991–1992 periods, the temporal and spatial variability in precipitation at fine scales (site level) was important enough to restrict generalities over the entire region for fuel load production. Four areas of interest, Etosha National Park (Namibia), Mongu (Zambia), Kasama (Zambia), and Kruger National Park (South Africa), were selected to reconstruct an aridity gradient and analyze their fuel load variability over the two years. These areas presented contrasting fuel load distributions for the two very different studied periods with arid areas producing heavier fuel loads in 1999–2000, and the more humid areas producing heavier fuel loads in 1991–1992. The consequences of such fuel load variability and the use of such results are discussed. INDEX TERMS: 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 1615 Global Change: Biogeochemical processes (4805); 1640 Global Change: Remote sensing; 3354 Meteorology and Atmospheric Dynamics: Precipitation (1854); 9305 Information Related to Geographic Region: Africa; KEYWORDS: climate, precipitation, net primary production, Fire, NOVI, tree cover