Intensity I and degree of polarization P. The top figures show the sensitivity to cloud optical thickness for a cloud layer from 2–3 km altitude including cloud droplets with an effective radius r_eff of 10 μm. Cloud optical thicknesses τ at 550 nm range from 5 to 20. The middle row shows the sensitivity to cloud altitude for a cloud with τ = 10 and r_eff = 10μm. The bottom altitude of the 1 km thick cloud layer varies from 2 to 8 km. The bottom figures show the sensitivity to effective radius for a cloud layer with a bottom altitude of 2 km and τ = 10. The effective radius varies from 5 to 15 μm.