Regularized inversion method for retrieving aerosol size distribution based on volume scattering function data at near-infrared waveband

Based on volume scattering data at 0.86 um, a new method for retrieving aerosol size distribution functions was put forward. According to the characteristics of aerosol size distribution, size distribution function n (r) was broken into two part, whole-trend function H (r) and detail-describing function (r), and a new series of basis functions were advanced and employed to approach (r). To overcome ill-posed nature in retrieval process, Tikhonov regularization method was combined with Mie scattering theory to strengthen the capabilities to void the influence of measurement noise and errors caused by numerical integration. Retrieval simulations are performed with size distribution data measured by Anhui Institute of Optics and Fine Mechanics, which represents three different kinds of aerosol, urban, rural and oceanic. Results show that, when radius of particles is larger than 0.2 um, the curve of retrieved size distribution function nearly coincides with that of actual size distribution, and their correlation coefficient is larger than 0.98 on condition that measurement noise isn't larger than 50%. Good robustness is also exhibited in the model put forward here; however when radius is smaller than 0.15 um, there is some deviation when measurement noise is large. To overcome this problem, Junge-correction method and accumulation-mode-compensation method were put forward, corrected results of retrieval size distributions show great consistency with actual size distribution. Compared with retrieval method based on intelligent algorithm, method here is more effective and less time-consuming, and has advantage in retrieving the detail characteristics of aerosol size distribution.