The variable H (km) defines the top height of the boundary layer in the aerosol vertical distribution. In typical meteorological conditions the value of H ranges from 1 km to 3 km, with a typical mean value of 2 km.
If the user does not introduce any value for H, ALG will use by default
the predefined MODTRAN aerosol vertical distribution.
Instead, if the user introduces a value for H, ALG will use an exponential decay function to model the vertical
distribution of the extinction coefficient in the boundary layer following the approach in
(Hess et al., 1998). In this case, the default value
for the scale height will be Z=8 km.
This variable controls the extension of the boundary aerosol layer, which influences the absorption and scattering effects caused by aerosols.
Hess, M., Koepke, P., & Schult, I. (1998), "Optical properties of aerosols and clous: the software package OPAC." Bulletin of the Americal Meteorologic Soctiety. Vol. 79, No. 5, pp. 831‒ 844.