Frequency and distribution of forest, savanna, and crop fires over tropical regions during PEM-Tropics A

Advanced very high resolution radiometer 1.1 km resolution satellite radian ce data were used to locate active fires throughout much of the tropical re gion during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-Tropics (PEM-Tropics A) aircraft campaign, held in September and O ctober 1996. The spatial and temporal distributions of the fires in Austral ia, southern Africa, and South America are presented here. The number of fi res over northern Australia, central Africa, and South America appeared to decrease toward the end of the mission period. Fire over eastern Australia was widespread, and temporal patterns showed a somewhat consistent amount o f burning with periodic episodes of enhanced fire counts observed. At least one episode of enhanced fire counts corresponded to the passage of a front al system which brought conditions conducive to fire to the region, with st rong westerlies originating over the hot, dry interior continent. Regions t hat were affected by lower than normal rainfall during the previous wet sea son (e.g., northern Australia and southwestern Africa) showed relatively fe w fires during this period. This is consistent with a drought-induced decre ase in vegetation and therefore a decreased availability of fuel for burnin g. Alternatively, a heavier than normal previous wet season along the south eastern coast of South Africa may have contributed to high fuel loading and an associated relatively heavy amount of burning compared to data from pre vious years.