Comparison between the derived haze τ-spectra (at the selected altitudes of 59, 115, 217, and 315 km) and the spectra of a) tholins and b) alkane ices. Between 1 and 2 μm, we discarded the wavelength intervals (shown as dashed lines in Fig. 1a) in which the τ-spectra are most uncertain. a) The tholin spectra are adopted from the literature (Khare et al. 1984; Quirico et al. 2008; Gautier et al. 2012). b) Spectra measured (Clark et al. 2009) for the alkane powders C₆H₁₄ (hexane), C₁₀H₂₂ (decane), and C₂₀₊H₄₂₊ (paraffin) provide a satisfactory fit to the three major peaks of the haze τ-spectra at 2.3, 3.4, and 4.3 μm. The  ± 1σ error bars for the 1−1.6, 1.8−3, 3−3.9, and 3.9−4.8 μm intervals of the τ-spectra are shown.