Panels (a) and (b): vertical profiles of downflow filling factors. Panels (c) and (d): temperature difference ΔT = T_down − T_up between downflow and upflow regions. Except for the snapshot at t = 0 hr (black line), which is based on an average over the whole domain, the quantities are computed inside a cylinder with 25 Mm radius centered on the left spot (a) and (c) and right spot (b) and (d). In addition, we averaged 2 hr in time.