Comparison between the GRIS observed intensity profiles and those synthesised with the HAZEL code. Each panel corresponds to a reference profile that shows a distinct spectral shape, and whose location on the Sun is highlighted in Fig. 6. We used the same colour code as that figure for the observations, while synthetic profiles are plotted in black. The spectral range only contains the Si I 10827.1 Å, the He I 10830 Å triplet, and the telluric line at 10832 Å for visualisation purposes. In contrast, vertical dashed lines designate the rest wavelength of the mentioned spectral lines.