Comparison between the observed vertical magnetic field and the vertical magnetic field (B_z) in the zero-β model. The field of view covers the main sunspots in the active region. The top row presents the observed magnetic field with grayscale saturation at ±1000 G. The middle row shows B_z in the first layer in the computational domain. The bottom row compares the observed B_z and that in the data-driven model along the blue dashed lines, as marked in the top two rows.