Impacts of the Differential Phase of Incident Waves on the Polarimetric Variables From Hail

It is shown that in the simultaneous dual-polarization radar mode, the differential phase (
$\beta $
) between the orthogonally polarized waves impinging on hail affects the polarimetric variables. This effect is caused by interference of the polarized waves scattered by nonspherical particles. The
$\beta $
impact is considered for dry hail and water-coated hailstones. For the hailstones’ canting angles oriented uniformly relative to the vertical, reflectivity and differential reflectivity do not depend on
$\beta $
, but the correlation coefficient between the polarized waves and phase upon scattering do. Tumbling of falling hailstones is considered using the Fisher distribution of the orientation angles. It is shown that the
$\beta $
impact enhances with increasing tumbling. The
$\beta $
impact should be considered in hail detection methods utilizing the correlation coefficient. The potential of using the differential phase upon scattering in hail detection and sizing is also discussed.