Multiple scatter effects on the radar return from large hail

A modified form of the equation of radiative transfer is solved numerically in order to estimate the effects of multiple scattering on the backscattered radar signal. The returned signal from a hypothetical hailstorm composed of spherical hailstones of approximately 3-cm diameter is computed by means of the transfer equation, and the result is compared with that computed for the same storm but utilizing the conventional equation which neglects all multiple scattering. Results for optical depth τ = 0.48 show that multiple scattering effects enhance the backscattered signal by about 30%. This correction increases with optical depth, and for the larger hailstorms is probably quite significant.