Microwave dielectric properties of surface snow

First results from a recently developed surface sensor for measuring the dielectric constant of snow at about 1 GHz are reported together with ground-based measurements of brightness temperatures between 4.9 and 94 GHz. The data are used to derive spectra of complex dielectric constants of wet snow for frequencies between 1 and 100 GHz. The result is simple: Debye relaxation spectra with a constant relaxation frequency of 9 GHz appear in contradiction to the mixing formula of Polder and van Santen. A way of resolving this discrepancy is presented.