Spectrum of the detached layer derived from Fig. 12 (black dots) compared to scattering models of CO₂ (red) and H₂O (blue) clouds with various ice crystal particle sizes (effective radii: squares, 1 μm; triangles, 2 μm; stars: 0.1 μm). Models are from Vincendon et al. (2011) for the following visible optical depths (at a wavelength of 0.5 μm): 0.5 (red triangles), 0.35 (blue triangles), 0.2 (squares), 0.15 (blue stars). The observed cloud is either compatible with CO₂ particle sizes in the 1–2 μm range or water ice particle sizes of about 2 μm.