Evolution of the magnetic field of AR 11137 in the observations (top row) and four different simulations (second row from the top, no flows and constant diffusivity; third row from the top, flows according to the inflow parametrization based on the gradient of the magnetic field and flux-dependent diffusivity; fourth row from the top, observed flows and constant diffusivity; bottom row, observed flows and flux-dependent diffusivity). The simulations were initialized at t_90% + 0.5 days. The times are indicated in the upper left corner of the top panels. The diffusion in the cases of constant diffusivity is 250 km²s⁻¹. Reference arrows are given in the lower left corners of the second column. Red (blue) indicates positive (negative) radial magnetic field. All maps have the same saturation at ± the rounded maximum absolute field strength in the central 10° from all simulation time steps. The green (black) contours indicate levels of half and a quarter of the minimum and maximum magnetic field in the central 10° of the observation (of each simulation) for each time step individually.