Comparisons of pressure-temperature atmospheric profiles between present 1D (solid blue) and CO⁵BOLD RHD (dash-dot black) models, for different effective temperatures and surface gravities, as indicated in the panels for each curves. Pressure unit is dyne/cm^-2. Calibration of l_mix based on such comparisons yields for T_eff = 2880,log g = 4.0; for T_eff = 3200,log g = 4.0; for T_eff = 3470,log g = 5.0; for T_eff = 3960,log g = 5.0. The dot on each solid curve indicates the onset of convection and the triangle indicates the location of optical depth τ = 100 (Chabrier & Baraffe 1997) where the transition to the interior model is performed.