SAR applications in the 21st century

SAR image data from a variety of spaceborne and airborne sensors will be much more commonplace in the early 21st century. Why will SAR data be used in some applications and what will it be used for? Part of the answer lies in SAR's ability to provide high-resolution imagery, independent of cloud cover or sun illumination, and in the sensitivity of radar measurements to certain physical characteristics of the area being imaged, such as surface roughness, structure, dielectric constant and, to some extent, motion. Another part of the answer is provided by the high-resolution topography and topographic change maps which can be generated using the technique of SAR interferometry.