Aerosol Optical and Microphysical Characteristics Related to Vertical Distribution over Korea Using Aerosol Scale Height

Aerosol optical depth characterizes total aerosol loading in the atmospheric column but does not directly indicate its vertical distribution relative to the planetary boundary layer. This study investigates aerosol vertical structure over Daejeon, Korea, by integrating column aerosol optical properties from a sky radiometer, near-surface atmospheric extinction measurements, and planetary boundary layer height from reanalysis data. Aerosol scale height is derived from aerosol optical depth at 870 nm and near-surface extinction and is analyzed alongside aerosol optical and microphysical properties. Aerosol scale height exhibits substantial variability relative to the planetary boundary layer height, with the highest relative values occurring in spring and the lowest in autumn. An increase in aerosol scale height relative to the boundary layer is accompanied by a decrease in the Ångström exponent and an increase in the coarse-mode volume fraction. The coarse-mode enhancement is driven mainly by an increase in coarse-mode aerosol volume, whereas surface PM10 concentrations show only a weak relationship with variations in vertical structure. Single scattering albedo generally increases, indicating a more scattering dominated column aerosol population. These results demonstrate that combining aerosol scale height with planetary boundary layer height provides valuable information on aerosol vertical structure and the degree of correspondence between surface and column aerosol conditions.