Detailed measurement of scattering by a spheroidal particle having varying proportions of ice and water

A computer controlled open resonator is used to provide fast and detailed measurements of the extinction cross-section of an ice sphere at 10 GHz as it melts. A complete record of the extinction cross-section of the particle is obtained and this is compared with theories at several stages through the melting process, namely; as a dry ice sphere, as an ice sphere surrounded by a thin shell of water, as a sphere composed of a homogeneous mixture of ice and water, and finally as a small sphere composed largely of water. Data are given for several sizes of ice spheres which have an increasing mass of water adhering beneath them.