Above the surface velocity inversions, MURaM-QS dataset. Patches of 125 by 125 pixels² extracted from the transverse velocity fields v_D,t(τ, t_i) (left column) computed by the MURaM-QS simulation (Vögler et al., 2005) and (middle column) inferred by DeepVel at optical depths (top) τ ≈ 1, (middle) τ ≈ 0.1 and (bottom) τ ≈ 0.01. The vertical velocity v_ref,z(τ ≈ {1, 0.1, 0.01}, t_i) computed by the MURaM-QS simulation is displayed as colored background with a symmetrical threshold. (Right column) Scatterplots comparing amplitudes ||v_D,t|| to ||v_ref,t||. The black line represents the expected solution (i.e., a coefficient of determination R² = 1).