Feasibility of polarized all-sky imaging for aerosol characterization

[摘要] In this study, we investigate the method of polarized all-sky imaging withrespect to aerosol characterization. As a technical frame work for imageprocessing and analysis, we propose Zernike polynomials to decompose therelative Stokes parameter distributions. This defines a suitable andefficient feature vector which is also appealing because it is independentof calibration, circumvents overexposure problems and is robust againstpixel noise. We model the polarized radiances of realistic aerosol scenariosand construct the feature vector space of the key aerosol types in terms ofthe first two principal components describing the maximal variances. We showthat, using this representation, aerosol types can be clearly distinguishedwith respect to fine and coarse mode dominated size distribution and indexof refraction. We further investigate the individual influences of varyingaerosol properties and solar zenith angle. This suggests that polarizedall-sky imaging may improve aerosol characterization in combination with skyscanning radiometers of the existing Aerosol Robotic Network (AERONET)especially at low aerosol optical depths and low solar zenith angles.

[学科分类] 几何与拓扑