Abstract. The features of upper-air visibility at altitudes of 0.1, 0.3, and 0.5 km and
the two-dimensional haze characteristics in the northwest of downtown Beijing
were studied by using a multi-platform analysis during haze episodes between
17 December 2016 and 6 January 2017. Through the multi-platform data
analysis in hourly and daily variation, the upper-air visibility increased
along with the decrease of PM2.5 mass concentration. And the upper-air
visibility on non-haze days was about 3–5 times higher than that on haze
days with the ground-based Raman–Mie lidar data between 13 December 2016 and
11 January 2017. The vertical transport of pollutants can be inferred from
the delayed variation of upper-air visibility between high altitude and low
altitude. In addition, the two-dimensional haze characteristics could be
studied by analyzing the correlation between vertical haze parameters
(atmospheric boundary layer, haze thickness, and aerosol optical thickness)
and horizontal haze parameter (upper-air visibility). The characteristics of
multi-parameters have been analyzed and concluded for different haze levels.
De-noising and retrieving algorithm of Mie lidar data based on the particle filter and the Fernald method
