Water posteriors for simulations for a range of surface H₂O abundances from 1 bar to 10⁻⁷ bar at a resolution and S/N of R = 100 and S/N = 10, respectively. The black lines are the H₂O profiles in volume mixing ratios in log₁₀ (L) overlaying the H₂O posteriors. The left panel assumes an altitude-invariant profile for water, commonly used in retrievals. The center panel fixes the surface abundance and then assumes a scaled Earth-like profile. The right panel fixes the surface H₂O abundance and has diffusion and photochemical production at all other altitudes.