Radar, specifically imaging radar, provides a powerful tool for remote sensing, with the advantages of round-the-clock capability (due to independence from solar illumination) and all-weather performance (due to cloud penetration). Radar can penetrate modest depths into the Earth and allow glimpses below the surface of the Earthâuseful in detecting buried objects such as pipelines or mines. Imaging radar is an essential tool for maritime concerns, from tracking ships to tracking sea ice. This chapter develops the physics and nature of imaging radar.
Figure 8.1 illustrates some of the radar characteristics we will be interested in. The image from an airborne sensor combines observations at two wavelengths. Shades of yellow and blue differentiate regions of different surface roughness, and vegetated areas (golf courses and city parks) show up particularly well.
|