Most of the focus, thus far, has been on the size of the crystal and the density of the snow, and relatively little attention has been given to the effects of crystal shape in scattering passive microwave energy. The objective of this paper was to determine if the shape of snow crystals play a role in how microwave radiation is scattered. The snow crystals were frozen in the field with liquid nitrogen so that they could be transported, without being concerned about melt, to the scanning electron microscope laboratory. Detailed three dimensional images of these different crystal types have been made, and based on these observed shapes, a special particle scattering model was used to calculate how differently shaped crystals scatter the microwave energy. The results indicate that the shape of the crystal is insignificant is terms of how much energy is scattered.
Spherical crystals scatter as much microwave energy as hexagonal or elliptical crystals.
This is useful to know since it is much easier to devise algorithms that assume every crystal has a simple spherical shape than to try to account for the scattering from a number of different shapes.