Drivers of fire weather with a warming climate
Changes to the drivers of fire weather with a warming climate – a case study of southeast Tasmania
Abstract
Dynamically downscaled climate model simulations are used to examine the impact of a warming climate on the incidence of a synoptic typing comprising a deep cold front and strong prefrontal winds associated with many of the worst fires in Tasmania and the southeast Australian region. There is a projected increase in the frequency of this system through the century under a high emission scenario, driven mainly by an increase in the temperature of air masses, with little change in the strength of the systems. The downscaled simulations reproduce the synoptic type with greater fidelity than a typical global climate model. The model mean projection increase in frequency is smaller than for a group of global climate models, with a large model range and natural variability. A case study of an extreme fire weather day in Tasmania in January 2013 indicates a blocking Foehn effect and topographic channelling associated with this synoptic type contribute to higher fire danger in southeast Tasmania compared to the northwest. An increase in the frequency of extreme fire weather days, along with projected decrease in summer rainfall in western Tasmania is projected to have an impact on overall fire danger under a warming climate scenario.