Numerical simulation of the retrieval of aerosol size distribution from multiwavelength laser radar measurements

A numerical investigation was carried out into the feasibility of deriving the aerosol size distribution from aerosol volume extinction and backscattering coefficient measurements by a multiwavelength laser radar. This study employs the regularization method for matrix inversion with the first-order B-spline function as basis functions to approximate the aerosol size distribution. The results of numerical simulations show that (1) the effects of roundoff errors in the numerical calculation are negligible and the approximation errors in the size distribution by the B-spline function are small, (2) the reconstruction errors in the size distribution at its peak are about twice as large as the relative measurement errors when the Lagrange multiplier, which determines the degree of smoothness in the reconstruction, is suitably chosen, and (3) the variation in the complex refractive index due to the humidity change does not produce large errors in the size distribution.