Pixel-by-pixel 2D histogram distributions for the ℋ (viridis) and ℒ (magma) model by combining different times (t = 30.7, 95.0, and 153.3 kyr). The upper panel correlates the ${\mathrm{H}}_3^{+}$ column density obtained from KROME and ${\mathrm{H}}_3^{+}$ calculated as Eq. (14). The bottom panel shows the correlation between the e⁻ column density and its proxy calculated by Eq. (16). The solid black line represents a 1:1 straight line and serves as an indicator for the lineal correlation formed by the 2D histogram distributions. The grey shadow indicates a region spanning one order of magnitude (−0.5 and +0.5) around the 1:1 black line.