Using dual-polarized ALOS PALSAR data for detecting new fronts of deforestation in the Brazilian Amazonia

This study shows the use of dual-polarized L-band Synthetic Aperture Radar (SAR) data acquired by the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar sensor (PALSAR) system for differentiation between primary forest and new deforestation fronts. Results showed that the new deforested areas are not unequivocally detected in either of the single bands individually. Although most of the recent deforestation appears brighter than mature forests in the HH band, the identification of new deforestation using only this band depends on the stage of the clearing process. Then, the contribution of the HV band through a normalized difference index (NDI) is important for detection of the new deforested fronts. Results indicate that the method can be used as the basis for an operational programme to monitor deforestation in the Brazilian Amazonia.