Spectra averaged over the regions of the cloudlet (left panels) and the ring (right panels) defined in Fig. 6 for the following lines: ¹²CO (1–0), ¹³CO (1–0) and C¹⁸O(1–0) (in black, IRAM-30m); ¹²CO(2–1), ¹³CO (2–1) and C¹⁸O(2–1) (in blue, APEX); ¹²CO(3–2) and ¹³CO(3–2) (in grey, APEX). Spectral cubes were resampled to allow a direct comparison between the different spectra. Spatial resolutions of all transitions were modified to the nominal resolution of C¹⁸O (2–1), θ = 30.2′′. Spectral resolutions were set to 0.5 km s⁻¹ for IRAM 30m data and 0.25 km s⁻¹ for APEX data. On both panels, the v_LSR of IC443 is indicated with a vertical dashed line (at − 4.5 km s⁻¹).