Illustration of NRCRs as a function of the distance from the illuminated surface. Only one half (left) of the model width is shown (the model is symmetric). The plotted NRCR values correspond to a 1D vertical slab model with T = 6000 K and p = 0.5 dyn cm⁻². The full line shows the total NRCRs derived as a sum of hydrogen (short-dashed black line), Mg II (dash-dotted black line), and Ca II (long-dashed white line) NRCRs. The blue and red stripes represent the voxels. The first five voxels have sizes of 50 km, and the rest have sizes of 250 km.