An Analysis of Scattering from a Thin Saline Ice Layer

O 24 %o Due to the inhomogeneities and the high loss property of saline ice, scattering sources from such an ice layer have been attributed to either volume scattering or top boundary surface scattering. Detailed surface truth and ice properties were acquired during the CRREL 88 experiment along with backscattering multifrequency data to further pin down the scattering mechanisms. The geometric parameters of boundary surface and scatterers inside the ice layer have been mea- sured. In addition, temperature and salinity values are also measured to allow estimation of dielectric values from existing formulae. By applying a combined surface/volume scattering model to the multi- frequency data, the same surface and volume physical parameters allow the model to fit measurements at 5 and 10 GHz in active scat- tering and at 6.7 and 18.7 GHz in passive scattering. It is found that for thin saline ice (7.5 cm) major source of scattering comes from the bottom interface between ice and water at 5 GHz. At 10 GHz contri- bution from the bottom interface is still significant but the top inter- face is a more important contributor at large angles of incidence.