Feasibility of Retrieving Aerosol Concentration in the Atmospheric Boundary Layer Using Multitime Lidar Returns and Visual Range

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Abstract This paper studies the feasibility of retrieving aerosol concentrations in the planetary boundary layer (PBL) with a variational data assimilation (VDA) algorithm using dual-wavelength lidar returns and visual range simulated at multiple times. Aerosols are assumed to consist of nucleation, accumulation, and coarse modes, with each mode distributed in a gamma distribution. The VDA algorithm retrieves initial vertical profiles of aerosol concentrations of the three modes, which are predicted by a 1D PBL model. The accuracy of retrieved aerosol concentrations of the three modes is examined through a series of identical twin numerical experiments. For the VDA algorithm that uses data from a lidar wavelength pair (0.289, 11.15 μm), results show that 1) if both random and systematic errors in the observed data are less than 1.0 dB and the number densities of accumulation and coarse modes are, respectively, 0.025–0.25 and 0–1.25 × 10−3 times that of the nucleation mode, relative errors in the retrieved...