Mean ice particle size as a function of time for different positions of the atmospheric ice line. The different lines show the growth for different distances from the atmospheric ice line to the midplane, z_ice. From top to bottom z_ice =  0.4 H, 0.6 H, 1.0 H, 1.4 H,1.8 H and 3.0 H. Ice particles grow faster, and to larger sizes, the closer to the midplane the atmospheric ice line is. Full lines denote simulations with 10 000 particles, dashed lines 1000 particles and dotted lines 100 000 particles.