Backscatter properties of multitemporal TerraSAR-X data and the effects of influencing factors on burn severity evaluation, in a mediterranean pine forest

TerraSAR-X dual-polarized (HH and HV polarization) backscatter data have been investigated to assess the temporal backscatter stability of a burn scar in Spain. Analysis of the main factors influencing burn severity evaluation has been also carried out. The temporal stability of the backscatter was strong, unburned areas showing differences of less than 0.6 dB. For increasing burn severity the backscatter varied by up to 2 dB in highly burned areas ocated on slopes tilted towards the sensor. Heavy rainfall or moist vegetation increased the backscatter up to 1 dB. Steeper look angles resulted in significantly higher backscatter coefficients for HH polarization, while for HV polarization only marginal increase was observed. Association strength between backscatter and burn severity estimates improved with the size of the multi-look window, at the expenses however of spatial resolution. Even better results could be achieved at higher spatial resolution by applying a multi-temporal speckle filtering algorithm.