The Measurement and Study of Fundamental Processes in Microwave Scattering from Melting Ice Particles

Available from UMI in association with The British Library. Measurements are made of the extinction cross sections of melting ice particles using a newly developed computer-controlled open resonator. Results are obtained for many ice particles with radii ranging from 2.5 to 10 mm, over the frequency bandwidth 8-12 GHz. Use of the computer controlled open resonator allows accurate and detailed measurements of the scattering behaviour of the melting particle under test, and a complete record of the particle's extinction cross section is obtained throughout its life history. The results are compared with theory at several stages throughout the melting process; as dry ice spheres, as ice spheres surrounded with a water shell and as ice spheres with a water drop suspended beneath. From these observations, predictions are made regarding the sensitivity of dual linearly-polarised radar with frequency of operation. Values of extinction cross sections of melting ice particles are measured at 35 and 70 GHz using other open resonators. From these results a study of the effect of the formation of a water shell around an ice particle is made, and predictions are made regarding the diminution of the 'bright band' effect observed in radar meteorology.