Study of Coniferous Forests Using Multifrequency Polarimetric Synthetic-Aperture Radar

Specific features of radio reflection of coniferous forest in decimeter- and meter-wavelength ranges are considered. The study is stimulated by the upcoming (in five-to-seven years) spaceborne experiments using synthetic-aperture radars (SARs) working in the P-band (430 MHz), which is important for sounding of forests. Experimental results on the reflection characteristics of pine forests obtained with the aid of multifrequency polarimetric SAR are presented. Reflection from forests is simulated for the meter-wavelength range for horizontal (HH) and vertical (VV) polarizations. It is shown that different effects may determine reflection of meter-wavelength waves with HH and VV polarizations. New results on specific features of airborne and spaceborne radar images (RIs) of forests in the L, P, and VHF bands are obtained. Typical features of the RIs of coniferous forests are revealed. Such features are difficult to interpret and need to be further studied using RI analysis and results of simultaneous measurements of soil and forest parameters. Several examples show that RI interpretations may cause doubts concerning the correctness.