Notes. The inclusion or exclusion of TiO/VO and magnetic drag in the GCM models is indicated by the symbols ✓ and X, respectively. The χ² metric is computed as ${\chi }^2=\sum {(y_i-m_i)}^2/{\sigma }_i^2$, where y _i is the passband-integrated GCM value, and m _i and σ _i are the occultation depth measurement and uncertainty, respectively. The reduced χ² metric, ${\chi }_r^2$, is computed as ${\chi }_r^2={\chi }^2/N$, where N is the number of data points. The GCM models with TiO/VO (no drag and τ_fric = 10⁴ s) are shown in Fig. 9. The measured occultation depths used to compute the χ² and ${\chi }_r^2$ values are reported in Table 3. The rightmost 2 columns entitled ‘No Sp.Ch2’ report the metrics computed on all but the Spitzer/IRAC/Ch. 2 data point to account of the GCMs not modelling the high CO/CO₂ emission peak.