Massfraction of grains larger than 0.25 μm for τ_J = 6 (red lines) and τ_J = 2 (purple lines). For panels A–C, the A_max and γ values of the model with r_Si = 0.5 and σ_NIR = 10% are used. Forpanel D, we use the previous model but assume σ_NIR = 20%. For panels Eand F, we use the models with the albedo of the grains decreased by 10% and the asymmetry parameter decreased by 10%, respectively. The greyscale colour maps correspond to the red lines and the contours show 1σ and 2σ.