${\overline{R}}_{x_i}\mathrm{\Delta }{x}_i$ for atmosphere model SU0 and SU1. Different colors represent different physical parameters, i.e., temperature, density, the three magnetic-field components, and the LOS velocity. τ is the optical depth at the peak wavelength of the Mg I 12.32 μm line intensity, and τ₅₀₀ is the continuum optical depth at λ = 500 nm for model SU0. Note that the scale of τ₅₀₀ is uneven.