Application potentials of synthetic aperture radar interferometry for land-cover mapping and crop-height estimation

Synthetic aperture radar (SAR) interferometry is widely used for applications like digital elevation map generation and studies related to surface movement. However, SAR interferometry can also be exploited in many other areas. Here a few of the potential applications of SAR interferometry have been demonstrated by exploring its use in delineation and density mapping of forested areas, delineation of surface water extent under adverse weather conditions, which is useful during flood-mapping; detection of human settlement and crop-height estimation. This has been achieved by exploiting interferometric coherence, which is inversely related to the magnitude of random dislocation of scatterers between the two passes. The study indicated that interferometric coherence decreases with increase in forest density or increase in crop height. It was also observed that interferometric coherence over stable targets like settlement is quite high compared to other land-cover classes. In contrast, interferometric coherence is always low for unstable surfaces like the water surface. The study suggested that interferometric coherence is a parameter that provides valuable information, which is completely different from that of SAR backscatter. It was also observed that synergic use of SAR backscatter with InSAR coherence enhances the application potential of a SAR system as a whole towards many land-cover features.