Quantitative, Near Real-Time Mapping of Bushfires Through Integration of Optical and SAR Remote Sensing Techniques

Early detection of bushfire plays a crucial role in firefighting, fire modelling, and minimising losses of human lives and properties. However, current bushfire monitoring systems have an intrinsic shortcoming because only temperature difference between neighboring pixels is exploited. This paper proposes to also examine a range of other changes occur when a bushfire is ignited, for example, a reduction of vegetation cover, volume scattering of bush and trees, as well as height of vegetation. All of these can be readily measured by optical and radar satellites already in orbits in near real-time, that is, less than two hours after a satellite overpass. Cross-correlation of these measurements has the potential to significantly reduce false alarm of a bushfire, while improving the early detection and measurement of fire spots, and hence make the system much more robust. A case study near Sydney is included here based on Sentinel-1 SAR and Sentinel-2 optical satellite data collected on 10 and 11 October 2020, respectively. This research is a major step forward towards the operational and synergetic use of optical and SAR satellites in bushfire monitoring.