On developing a historical fire weather data-set for Australia

Abstract

The creation of a national historical fire weather data-set, extending from 1973 to 2008, is described. For this purpose, fire weather is described using the McArthur Forest Fire Danger Index (FFDI). A detailed deconstruction of the FFDI and its sensitivities is presented. To create the data-set, meteorological measurements of air temperature, relative humidity, wind speed and rainfall are required. A total of 77 stations are used. At many of these stations, the input data are non-homogeneous. A particularly concerning issue for the fire weather data-set here is the inhomogeneity of the wind measurements, largely a consequence of different measurement instrumentation and methodologies implemented over the decades. Monte Carlo techniques are used to investigate the sensitivity of the distribution of the FFDI to changes in the distribution of the wind. The mean wind speed is shown to have the largest effect. A method for estimating the magnitude of the errors introduced is presented.