Scattering matrices and integral scattering quantities of laboratory-characterized silicate and ice particles

Mueller scattering matrices and integral scattering quantities of four different scattering particle shapes, two refractive indices, and various size parameters computed using ADDA (v1.2; Yurkin and Hoekstra, JQSRT 112, pp. 2234-2247, 2011). The file name consists of the particle shape designation (A-D), the refractive index designation ("m254" depicts a silicate-rich particle: m = 2.54 + 0.01i; "m178" depicts an ice-rich particle with impurities: m = 1.78 + 0.001i; both at microwave frequencies), and the volume-equivalent size parameter (spherical-volume-equivalent particle perimeter length per wavelength) ranging from 0.25 to 7-16 depending on the shape type. "CS" refers to Cross Sections, which includes the extinction cross section, the extinction efficiency, the absorption cross section, and the absorption efficiency. The cross sections assume a wavelength of 6.283185307. All Mueller scattering matrices are 4 x 4 matrices for 180 different scattering angles, and orientation-averaged over hundreds or thousands of orientations. The scattering matrix files include a descriptive header line. In the ADDA computations, the polarizability prescription is "Lattice dispersion relation" when |m| < 2 and "Filtered coupled dipoles" when |m| > 2. The Interaction term prescription is "Point dipoles" when |m| < 2 and "Filtered Green's tensor" when |m| > 2.

The corresponding scatterer shape models are given in the files ending "dipoles_x12.out". ADDA uses scatterer shape models that have been discretized into equally-sized cubic voxels. The shape model files list the x, y, and z coordinates of each voxel. The shape models have been scaled to optimize computation times but ensuring that the number of dipoles per wavelength is greater than 10|m| for each size parameter. The given shape model fulfills this condition for a size parameter of 12. The particle shape models have been derived from atmospheric dust particles by scanning-electron microscopes (Lindqvist et al., Atmos. Chem. Phys. 14, 143-157, 2014).