Polarimetric radar remote sensing of hailstorms

Polarization is one of the basic characteristics of an electromagnetic wave. Utilization of polarization in remote sensing has been shown to increase the available information about the scattering medium. This research focuses on polarimetric radar remote sensing of hailstorms and includes electromagnetic scattering computations, simulations of radar observables and analyses of experimental measurements polarimetric radar.; The electromagnetic scattering matrix is computed at S-c, C-, and X-band wavelengths for hailstones of different sizes, shapes, and dielectric properties using the T-matrix method. The effect of hailstone size, shape, orientation and melting on radar observables are studied. It is found that the size distribution parameters and the melting of hailstones strongly affect all the radar observables considered in this study. The mean canting angle mainly influences the radar observables based on differential measurements.; Data from polarimetric radar measurements in hail are analyzed and interesting features are identified and interpreted using the results from the computational studies. The effects of the hailstone melting on radar observables are also observed with the experimental data. The possibility of estimating the melting level within a hailshaft using radar measurements is hypothesized. Large areas of both positive and negative differential reflectivity exist in the hail regions indicating that the hail medium is not isotropic.; Simulations of radar measurements in hailstorms are performed. These simulations are based on the computational and experimental results, and contain information on the radar observables and hailfall parameters at different heights inside the storm. Using the simulated data, various detection techniques are evaluated and it is found that the differential reflectivity hail signal performs better than the others. A new hail detection algorithm using the specific propagation phase shift is also derived. The utilization of radar observables for measuring different parameters of the hail medium are also discussed and relationships between several radar observables and hailfall parameters are determined. These relationships are shown to be different at different heights as a result of hailstone melting.