The relationship between the monsoonal summer rain and dry-season fire activity of northern Australia

Fire is an essential element of the northern Australian ecosystems with extensive areas burnt each year. The basic climate condition of high rainfall during the summer monsoon, followed by an extended warm dry winter, along with highly combustible vegetation (much of which grows rapidly during summer and senesces during winter), creates a highly flammable environment. These vegetation conditions change under various naturally occurring climate oscillations such as El Nino-Southern Oscillation (ENSO). The present paper investigates the link between burnt areas of northern Australia, rainfall, the Southern Oscillation Index (SOI) and sea surface temperatures (SST) for a 9-year period (19972005). The burnt area distribution is compared with the strength and timing of the monthly averaged rainfall, SOI and SST. Results indicate a strong relationship between antecedent rainfall and ENSO indices with area burnt. This is especially strong between the burnt areas of June-October and the preceding rainfall of November-March (r = 0.90), the SOI of November-February (r = 0.78) and the SST of June-August (r = -0.64). The results from the present study reveal the ability to forecast annual burnt areas and present some of the dynamics of the climate-fire interactions and their value for management systems.