Characteristics of the surface vertical velocity predicted by 3D solar models. Left panel: time-averaged distribution of surface vertical velocity. The histograms were calculated based on 30 equidistant bins between −10 and 10 km s⁻¹, where positive velocities indicate downflow moving towards the stellar interior. The distribution function was normalised in the same way as the bolometric intensity (Fig. 10) so that the total area under it is equal to one. Right panel: spatially resolved surface vertical velocity pattern from one snapshot of the sunA09 simulation.