Observations of the boundary layer structure and aerosol properties over Xi'an using an eye-safe Mie scattering Lidar

摘要

An eye-safe micro-pulsed Mie scattering lidar (MPL) system at a wavelength of 532. nm was built for routine observations of atmospheric optical properties of the lower troposphere. The lidar is operated in an analog mode with three-dimensional (3D) scanning capability. Observations were carried out for obtaining detailed information of the urban boundary layer (UBL) over Xi'an, China. The parameters that can be measured include aerosol extinction coefficient and optical depth (AOD), structure of the UBL, and the mixed layer depth (MLD). The results indicate that the height of UBL shows both temporal and spatial variations over Xi'an. It is generally lower in the early morning and dusk than during the daytime. MLD is driven by the convective air motions and strongly correlated with the aerosol diurnal changes which tend to fall during night and rise during day.