A Climatology of Wildfire Weather for Victoria, Australia: Based on a Hi-Resolution 40-year Mesoscale Gridded Fire Weather Dataset

Abstract:

Weather and climate are essential components in understanding wildfire characteristics and improving fire management. A high spatial and temporal resolution climatology of fire weather is vital for examining relationships, determining wildfire risks and basing fire management decisions upon. A homogeneous 41-year (1972–2012) hourly 4-km gridded climate dataset for the fire-prone state of Victoria, Australia has been generated using a combination of mesoscale modelling, global reanalysis data, surface observations, and historic observed rainfall analyses. Outputs include surface weather variables such as hourly temperature, relative humidity, wind speed and wind direction. In addition, daily drought indices have been calculated and these have been used to calculate a commonly used fire danger index.

This new dataset allows for an almost limitless opportunity for hitherto unavailable analyses – such as fields of percentiles of fire danger indices values, analysis of periods exceeding thresholds at any location, inter-annual and regional variations of fire season characteristics, analysis of prescribed burning windows, and identifying trends over the 41-year period. Furthermore, the hourly mesoscale wind fields provide a homogeneous long-period data set with which to drive fire spread models. The opportunities to advance wildfire research for this region and thereby provide information to improve risk analysis and fire management are immense.

This presentation describes the generation of the dataset, evaluation of the outputs and highlights its use and relevance for fire management. In particular, frequency of exceedance of both extreme values (for resource allocation planning), and also frequencies whereby multiple parameters mutually fall within the prescribed burning guidelines, and its interannual variation, will be discussed.