Measured and modelled scattering properties of simulated particles of granular and spongy hail at microwave and millimetre-wave frequencies

The detailed scattering properties of single spherical particles which have been created artificially to represent particles of hail have been measured together with the physical properties of the particles, namely size, shape and percentage content of ice, water and air as applying continuously throughout the process of melting. Specifically, the types of particles represent granular hail and spongy hail. The measurements are of extinction (total-loss) cross-section, and were taken at frequencies of 8, 10, 12, 34 and 70 GHz. Models for describing the observed scattering behaviour are tested, and differentiation is made between the results and models which apply to each of the types of particles, the observation and implications of collapsing size of the two types of particles being an important feature. For types and frequencies, the sets of results allow evaluations to be made of the ratio of the maximum cross-section exhibited during melting to the initial cross-section of a particle when dry.

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