Preliminary Report on Measurements of Forest Canopies with C-Band Radar Scatterometer at NASA/NSTL

This paper presents preliminary results of C-band radar scatterometer measurements of forest canopies of southeastern forests in the vicinity of NASA/NSTL. The results are as follows: 1) radar backscattering coefficients (BSC´s) of deciduous forests such as oak, maple, blackgum, and cypress are higher than those of coniferous forests such as slash pine plantation and natural pine; 2) at a large incidence angle, where polarization effect is significant, and by ranging measurement, the VV polarization BSC´s obtain peak value at the first few meters from the canopy top and decrease rather quickly, while the HH polarization BSC´s obtain peak value at longer distances from the canopy top and decrease rather slowly through the canopy; 3) using the active radar calibrator for tree canopy attenuation measurement of a dense and a sparse live oak, it is found that the tree canopies with higher attenuations have higher BSC´s for all three polarizations, with VV polarization containing the largest differential (2.2 dB).