Decomposition of the CO₂ signal into its individual contributions. Top panel: CO₂ template spectrum (dark blue) and the 18 wavelength segments covered by the K2148 setting (shaded regions). Bottom panel: decomposition of the S/N=3.6 peak signal of the CO₂ CCF into its contributions from individual nights and wavelength segments given in terms of the per cent of the cumulative signal. Wavelength segments in the top panel and corresponding contribution in the bottom panel are indicated with blue lines connecting the two panels for easier identification.