All models used in this work (see Sec. 3 for details), represented as the flux received from the star during transit relative to the out-of-transit stellar flux as a function of wavelengths (left). From left to right, we show the 1D models [panels (a) and (b)] and GCMs [panels (c) and (d)]. In each plot, the gray line plots the model in which both molecular species were studied in this work, i.e., water and carbon monoxide. Only H₂O [panels (a),(c)] and only CO [panels (b),(d)] models are overplotted with blue and green colors, respectively, in the top and bottom panels. Overall, GCMs (darker colors) have a deeper absorption than the 1D models (lighter colors) due to a different starting pressure at the bottom of the atmosphere. A zoom over a smaller wavelength range of only H₂O (top panel) and only CO (bottom panel) 1D and 3D models is shown (right).