FIRE WEATHER IN THE WET-DRY TROPICS OF THE WORLD-HERITAGE-KAKADU-NATIONAL-PARK, AUSTRALIA

Seasonal changes of weather and fuels in the wet-dry tropics are drama tic; fires follow suit. In this paper, we examine quantitatively rainf all, evaporation, wind, temperature and humidity information, and indi ces derived from them, for Kapalga Research Station and nearby Jabiru in World Heritage Kakadu National Park, Northern Australia. At Kapalga , the average annual rainfall of about 1200 mm mostly falls during a 6 month wet season. Grasses, green in the wet, begin to desiccate durin g the early dry season. Perennial grasses cure more slowly than the an nuals, and grasses in drainages cure later than those on ridges. Fire weather is usually most severe in September-October (late dry season) and least severe in January-February (late wet season). As the dry sea son progresses to its peak, daily wind patterns change, daily maximum temperatures increase to an average of 36 degrees C, dew points drop t o a minimum, and soil moisture is severely depleted. In the early dry season (cf, later), fires have a greater tendency to go out at night c ompared with later perhaps because winds then are calmer, fuels are mo re discontinuous, and relights from burning logs are less likely to oc cur. Fire weather in the north of Australia appears less severe than t hat in the southeast of the continent where socially disastrous fires occur periodically.