REFF contour plots in 633 nm of the original samples measured at 40° incident zenith. In each contour plot, the origin (x=0°,y=0°) represents the nadir direction (viewing straight down) and the radial distance from the origin corresponds to the zenith angle. The incident beam is aligned with the positive y-axis, which serves as the azimuthal reference direction (0° azimuth). Relative azimuth angles are measured clockwise from this reference.