Comparison of the ⁴⁰Ar number densities with data from LADEE’s NMS, Apollo’s LACE instrument (J. A. Kegerreis et al. 2017), and surface-projected CHACE-2 data (M. B. Dhanya et al. 2021), separated into the first six 10 km layers based on the simulation’s discretization. The blue band around the simulation results represents one standard deviation of uncertainty, based on the variance within the MC steps. For comparison, the results of a simulation without topography have been added as blue dashed lines. The shaded gray area marks the lunar nightside.