Synthetic day-side (left) and transmission (right) spectra of HD 189733b with the nominal mechanism (green curve) compared to the one corresponding to the GRIMECH mechanism (red curve) and to the thermochemical equilibrium (blue curve). The dark curve is obtained when NH₃ is removed from the model. The day-side fluxes are given as brightness temperatures (T_b). Because of the reflection component, note that the link between T_b and the atmospheric thermal profile is altered below 2 μm. The transmission spectrum is given as the apparent planetary radius. The data points obtained from various observations are also shown.