Algorithm for vertical distribution of boundary layer aerosol components in remote sensing data

Abstract

Abstract. The vertical distribution of atmospheric aerosol components is vital to the estimation of radiation forcing and the catalysis of atmospheric photochemical processes. Based on the synergy of ground-based lidar and sun-photometer, this paper developed a new algorithm to get the vertical mass concentration profiles of fine aerosol components for the first time. The sky radiance at multiple scatter angles, the total optical depth (TOD) at 440, 675, 870, and 1020 nm, and the lidar signals at 532 nm and 1064 nm were applied to retrieve the aerosol properties. Besides, the internal mixing model and normalized volume size distribution model were constructed, according to the absorption and water-solubility of aerosol components, to separate the profiles of black carbon (BC), water-insoluble organic matter (WIOM), water-soluble organic matter (WSOM), ammonium nitrate-like (AN), and fine aerosol water content (AW). The results showed a reasonable vertical distribution of aerosol components compared with in situ observations and reanalysis data. The estimated and observed BC concentration matched well with a correlation coefficient up to 0.91, while there was an evident overestimation of OM (NMB=0.98). And the retrieved AN concentrations were closer to the simulated results (the correlation coefficient of 0.85), especially in the polluted condition. The correlations of BC and OM were weaker relatively, with a correlation coefficient of about 0.5. Besides, the uncertainties caused by input parameters (i.e. RH, volume concentration, and extinction coefficients) were assessed by Monte Carlo method. AN and AW had smaller uncertainties at higher RH. In this paper, the algorithm was also applied to the remote sensing measurements of Beijing and two typical cases were presented. Under the clean condition with low RH, there were comparable AN and WIOM but peaking at different altitudes. While in the polluted case, AN was dominant and the maximum mass concentration occurred near the surface. We expected the algorithm can provide a new idea for lidar inversion and promote the development of aerosol components profiles.