A: comparison between observed and best-fit simulated HCN (4-3) lines (black and red, respectively, upper panel), and the difference between the observed and fitted spectra (lower panel). B: retrieved temperature. C: corresponding averaging kernels. D: corresponding normalised contribution functions. E: HCN distribution derived from the spectrum. F: corresponding averaging kernels. G: corresponding normalised contribution functions. In (B) and (E), the black and red lines show the initial and retrieved profiles, respectively, and the pink shadow shows the error bars. AVKs and contributionfunctions are shown for selected altitudes and frequencies, respectively, for better representation (see plot legends).