Modeling of melting-snow particles for scattering and attenuation calculations

Attenuation by the melting layer is an important consideration in the design of satellite links and in interference calculations, particularly at the higher microwave frequencies. While the total attenuation through the layer is needed for fade-margin allowance, the local specific attenuation within the layer is a significant factor in the accurate determination of interference levels due to melting layer scatter. Similarly, the scattering by the layer has an equally important role. In a recent paper by Kharadly and Hulays (see Proc. ISAP´92,p.1069,1992), it is shown that attenuation is strongly influenced by three main parameters. These are: (a) the melting profile, (b) the velocity profile and (c) the average-density of the melting-snow particles. In evaluating the relative effect of each of these parameters (which are not independent), a melting-snow particle was represented by the conventional model which is used by some investigators-a dry snow core uniformly surrounded by a water layer. The authors examine several models of melting-snow particles and evaluate their effect on the predicted attenuation and backscattering cross section of the melting layer