Modelling the fire weather of Black Saturday

This presentation will describe results from a very high resolution (0.004°) numerical weather prediction (NWP) simulation of the Victorian fire weather of Black Saturday, 7 February 2009. The simulation has been performed using the Australian Community Climate Earth Simulation System (ACCESS), and has involved a sequence of nested limited area model (LAM) runs embedded in the ACCESS global model run. At lead times of around 24 hours, the model successfully captures the progress of the wind change across the study region, with timing errors of 30 to 60 minutes. Comparisons with surface and upper-level observations indicate that the model performs well at these high resolutions. Boundary-layer rolls are modelled ahead of the change, with small-scale vortices being modelled along the frontal boundary. The formation of an undular bore on the nocturnal inversion was also modelled. We expect that these features would likely have a noticeable, but localised, impact on fire behaviour.

This work forms part of a project, funded by the Bushfire Cooperative Research Centre, which aims to produce very high resolution simulations of significant recent fire events, so as to (i) better understand the meteorology of those events (in the first instance, Black Saturday) and (ii) support the research of other Bushfire CRC project components by providing relevant meteorological data. Intended downstream applications of these results include inputs to fire intensity and spread models, fire decision support tools, understanding and predicting smoke dispersion, and understanding and predicting small-scale weather variability relevant to fire behaviour.