Measurement of radar cross-section and complex dielectric properties of forest fire ash

Remote sensing of fires has become a major topic of discussion in Australia. The introduction of infrared (IR) and optical systems has been a key technology for this area. Although IR and optical systems provide good coverage and detection capabilities, they are still limited by signature absorption from smoke, water, terrain and solid obstacles (i.e. flora, rocks, etc). Microwave-based sensing is seen by some as an alternative solution to help detect and track fires over larger distances. The use of existing microwave technologies such as ground-based weather radar for detecting large fires is nothing new, however; early stage detection (area burnt as close to 1m² in ground surface area) has not yet been researched. For the earliest possible stage of detection, the volumetric scattering of ash particulates needs to be understood in further detail. Presented are the radar cross-section (RCS) measurements and complex dielectric properties of ash samples taken from Australian flora.