Measurement and simulation of L-band emission for a larch forest stand

In this work, there was tested a possibility to establish quantitative relationship between the moisture of forest stand, as a system of the trees, litter, and soil layers, and the radiometer antenna temperature. The radio brightnesses of radiometer antenna at L-band was measured as a function of viewing angle for both the V and H polarizations, with the antenna being directed at the larch forest stand. The radiometer was mounted on the tower at the height of 21.5 m, with the viewing angle being changed from close to the nadir to the horizon. The larch forest stand of 100 × 100 m², used as an object of study, was located 50 km to the north from the city of Krasnoyarsk, Russia, with the average tree height, diameter, and density of trees being of 13.8 m, 0.1 m, and 0.38 trees/m². All data were recorded in August 2001. In the theoretical model developed for predicting the radiometer antenna temperature, the forest canopy was considered as a three layers medium with each layer having its own complex dielectric permittivity. The latter was calculated using the refractive mixing dielectric model with its parameters being determined experimentally in L-band through the laboratory measurements using the data collected in situ at the site of measurement. As a result, there have been proved the possibility of using comprehensive radiobrightness and dielectric models as a physical basis in developing processing algorithms for radiometric remote sensing of moisture, on the forested territories.