Detection significance of the injected signal versus log₁₀ VMR for each model configuration. Left panel: recovered signal using all quantum transitions. Second panel: same signal multiplied by 0.48 as found in Sect. 2.1. Third panel: recovered signal using specific quantum transitions and the fourth panel shows the same signal multiplied by 0.90 as obtained in Sect. 2.4. The considered temperatures are displayed as different shades of blue. Two rightmost panels: detection significances of models with T = 1500 K, H = 1080 km, and T = 3000 K, H = 540 km in light green and dark green, respectively. The horizontal dashed lines at 4σ represent our detection thresholds.