In this study, the radar polarimetric variables at an X-band wavelength are first calculated using a T-Matrix approach for aggregates represented by prolate spheroids with a fixed aspect ratio of 0.4 and a prescribed particle size distribution (PSD). The elevation angles between the prolate spheroidsâ€™ maximum dimension and the horizontal plane follow a Gaussian distribution of zero mean and 10Â° standard deviation, whereas the azimuth angles are random. Next, a projected PSD is generated from the projections of the prolate spheroids onto a plane perpendicular to a horizontal viewing direction; the average of the projected aspect ratios is 0.6. Then the radar polarimetric variables are calculated for oblate spheroids with an aspect ratio of 0.6 following the projected PSD, and compared with the calculations for the prolate spheroids. Sensitivity to different PSDs are tested.

Preliminary results show that the average size from the projected PSDs is 26% smaller than the average size from the real PSDs for the 0.4 aspect ratio prolate spheroid. The reflectivity difference is 4-8 dB between the two types of spheroids at an X-band wavelength. Z_{DR} and K_{DP} are biased by 40-55% and 60-67%, respectively, if the oblate spheroids are used to represent the prolate spheroids. In future work, a combination of different spheroid shapes will be used to represent real aggregates rather than a single prolate shape. The radar wavelength will be expanded to S- and Ka-bands. More orientation distributions will be included because aggregates tend to have a wide range of orientations from the horizontal plane.