Observations of L- and C-band Backscatter and a Semi-empirical Backscattering Model Approach from a Forest-snow-ground System

Observations of Land C-band backscatter from snow cover are presented at all polarizations. Airborne passive-microwave data was collected in Northern Finland during EMAC’95 (European Multi-sensor Airborne Campaign-95). The measurements cover the 6.8–18.7 GHz frequency range with both vertical and horizontal polarizations. The empirical SAR data were acquired by EMISAR of Technical University of Denmark over the city of Oulu in Northern Finland during EMAC’95. Airborne measurements were conducted on 22–23 March, and on 2–3 May 1995. The land-use map of the test sites was obtained from the National Land Survey of Finland. This study combines the semi-empirical and empirical models that were developed. Applicability of the forest transmissivity formulas developed by using the different data sets of passive and active sensors is shown. Because of the effect of dry snow at C-band is more visible than at L-band. A C-band semi-empirical backscattering model is developed for the forest-snow-ground system.