Changes in surface reflectance from wildfires on the Australian continent measured by MODIS

Atmospherically corrected Moderate Resolution Imaging Spectroradiometer (MODIS) data have been used to measure the changes in surface reflectance induced by fires. To account for observation geometry effects a kernel driven bi-directional reflectance factor model was applied. Whereas the blue, green, red and shortwave infrared bands show no consistent behaviour, the near-infrared bands almost always show a strong reduction in reflectance. An angular dependence of the change in reflectance was not found in this study. Different biogeographical regions exhibit different spectral reflectance changes due to the different types of fuel being burnt (green/living versus dry/dead vegetation). This difference is also reflected in the seasonality of the green, red, near-infrared and shortwave infrared bands for the tropics. The conclusion of this study is that the near-infrared bands are the most suitable bands for an automatic burnt area mapping algorithm using optical, reflective remote sensing data. The results also suggest that satellite remote sensing might be able provide additional information about burning conditions which are strongly affecting greenhouse gas emissions.