Effect of Scale on the Correlation Between Topography and Canopy Elevations in an Airborne InSAR Product Over AMAZONIA

A Ditigal Terrain Model (DTM) and a Digital Surface Model (DSM), obtained by P and X band SAR interferometry respectively and available in the “Radiografia da Amazônia” product, are analyzed. The slopes computed from the two altimetric signals are compared in order to show how the correlation between the ground and the top of canopy varies with regards to scale in an Amazonian landscape. The threshold distance over which the slope (and therefore the geomorphologic properties) of the ground can be derived from the DSM with a limited error is found to be approximately 50 meters. Since DSMs are more widely available than DTMs, this study provides criteria for the users to evaluate the suitability of DSMs to describe the geomorphology.