Observed Associations between Fire Danger and Climate Modes and Their Representation in ACCESS-S2

Abstract

The increasing frequency and severity of wildfires in Australia, driven by climate change, pose a significant threat to ecosystems, lives, and property. This study examines the impact of climate drivers, specifically El Ni & ntilde;o-Southern Oscillation (ENSO), Indian Ocean dipole (IOD), Southern Annular Mode (SAM), Madden-Julian oscillation (MJO), and two modes of persistent high pressure in the Australia-Pacific region, on extreme fi re danger. By analyzing observed and simulated fi re danger in relation to these climate drivers, we aim to enhance our understanding of climate-fire mechanisms and contribute to Australia's bushfire preparedness. Our fi ndings indicate that all assessed drivers influence extreme fi re danger, with key influences related to the drivers' established relationships with rainfall and temperature. El Ni & ntilde;o, positive IOD, and negative SAM events generally increase extreme fi re danger across most of Australia and in most seasons. The two modes of Australian blocking exhibit similar effects, varying spatially. Specific phases of the MJO have significant seasonal relationships with fi re danger. In some instances, increased fi re danger is not directly linked to temperature or precipitation changes but rather driven by remote teleconnections, airflow, or pressure anomalies. Evaluating the accuracy of weather and climate forecasting systems in representing these relationships is crucial for the effective prediction and mitigation of fi re hazards. The leading Australian climate simulation model effectively reproduces observed relationships but reveals biases in capturing certain aspects of climate variability. Advancements in this fi eld would enhance fi re weather forecasts, including those by the Australian Bureau of Meteorology with lead times of up to 4 months. SIGNIFICANCE STATEMENT: This assessment of climate-fire relationships and modeling accuracy is pivotal in understanding the factors behind severe fi re events and improving future predictions and mitigation. Prior research has already established links between elevated fi re weather conditions and these climate drivers, highlighting their potential for predicting severe fi re events. This study aims to deepen our comprehension of the factors driving severe fi re events and facilitate improved bushfire risk management in Australia. Show more