Australia’s need for a powerful and predictive bushfire modelling capability has never been clearer. The 2019-20 bushfire season showed just how widespread, unpredictable and terrifying bushfires can be. The Bureau of Meteorology, with the help of the NCI supercomputer, is developing new modelling tools that are already helping authorities deepen their understanding of fires and their behaviour.

ACCESS-Fire is the model that the Bureau of Meteorology is developing to simulate bushfires and their interaction with the atmosphere. State and Territory fire agencies and the Bushfire and Natural Hazards Centre for Collaborative Research have been key players in this project since its inception.

Fire agencies currently run models in real time to predict how fire may spread. Designed to run on laptops out in the field, those models capture a limited view of the complex structure of the atmosphere. Models run on a supercomputer however, can incorporate a myriad of complex information. ACCESS-Fire includes physics that models the heat, moisture and air flows in and around a fire front at landscape scale.

Taking observations of weather conditions inside a fire is understandably difficult. Wind speed, wind direction, air pressure, and air temperature are all key variables that we can only really understand through large, high-resolution computational models. Recent improvements to the ACCESS-Fire model’s scientific detail, as well as its computational performance, make it possible to find out new details about bushfires and their propagation. For example, Bureau of Meteorology researchers Drs Mika Peace and Jeff Kepert identified the specific set of weather conditions that led to an unexpected ember attack during the Waroona fire in Western Australia in 2016. With this new knowledge, fire fighters can better plan their tactics and the public safety response during future fires.

The more complex structure of the ACCESS-Fire model makes it an improved tool for dealing with fire extremes and unexpected situations, such as when fires become very large and start creating thunderstorms with the heat and moisture they produce. Supercomputing performance and carefully designed model codes make understanding these phenomena possible.

This model relies on all facets of the Gadi supercomputer: many performant processors, large memory, and fast and powerful storage. Due to the complexity of the model, it is not yet suitable for operational use during a bushfire, but the researchers are gradually moving in that direction. Dr Peace says, “It’s wonderful to get to work on something that resonates with everyone across our society. Bushfires affect us all, so contributing to that is both exciting and fascinating.”

This research highlight was originally published in the 2019-20 NCI Annual Report.