Butterfly diagram of solar Babcock-Leighton model with C_S = 30 and D = 4.2 × 10⁶, for B_ϕ at r = 0.7 and B_r at the surface. As the radial component diagram is much more contrasted here, we propose some contours, using consistent colors, to illustrate weak patterns that are not saturated enough. The vertical dashed line corresponds to the reversal of poloidal field from negative to positive at the poles, coinciding with the positive maximum of toroidal field at the base of CZ. A logarithmic color scale has been chosen to represent the bottom panel.