B_z, ∇_h ⋅ v_h, ∇v_z at the surface (FOV 96 × 96 Mm²). Long-lasting downward velocities are displayed as red points using the threshold of −0.25 km s⁻¹. Left: B_z (grey levels), averaged over 12 h. Middle: ∇_h ⋅ v_h averaged over 12 h. Bright and dark correspond to diverging and converging flows, respectively. Right: dv_z/dz averaged over 4 h. Bright and dark correspond to upward and downward vertical gradient, respectively.