Temporal evolution of metrics comparing the horizontal magnetic field of the observed input magnetograms vs. the simulated output magnetograms. Top and middle panels: slope and Pearson coefficient respectively, for B_x (purple) and B_y (blue). Bottom panel: mean angle between the input and output fields (orange). The solid lines use a mask of 250 G, while the dashed lines use a mask of 1000 G on the magnitude of the magnetic field vector.