Intensity I and degree of polarization P. The top figures show the sensitivity to ice water cloud optical thickness (at 550 nm) for a cloud layer from 10–11 km altitude including ice crystals with an effective radius r_eff of 30 μm. Cloud optical thicknesses τ range from 0.5 to 5. The second row shows the sensitivity to cloud altitude for a cloud with τ = 2 and r_eff = 30μm. The bottom altitude of the 1 km thick cloud layer varies from 8 to 12 km. The third row shows the sensitivity to the effective radius for a cloud layer with a bottom altitude of 10 km and τ = 2. The effective radius is varied from 10 to 60 μm. The bottom panels show the sensitivity to surface albedo.