1D b^1D(τ_R) and median 2D b^2D(τ_R) departures as a function of τ_R for the lower 3s⁵ S (blue) and upper 3p⁵ P (red) levels (dashed and solid lines, respectively) for a particular cycle. The median 2D departures are results of the horizontal average along the surfaces τ_R = const. Departures from LTE b^1D(τ_R) are based on interpolation of results of calculations using 1D hydrostatic models by fixing .