Abstract

Ground-based sunphotometer observation of direct and scattered solar radiation is a traditional tool for providing data on aerosol optical properties. Spectral transmission and solar aureole measurements provide an optical source of aerosol information, which can be inverted for retrieval of microphysical properties (particle size distribution and refractive index). However, to infer these aerosol properties from ground-based remote-sensing measurements, special numerical inversion methods should be developed and applied. We propose two improvements to the existing inversion techniques employed to derive aerosol microphysical properties from combined atmospheric transmission and solar aureole measurements. First, the aerosol refractive index is directly included in the inversion procedure and is retrieved simultaneously with the particle size spectra. Second, we allow for real or effective instrumental pointing errors by including a correction factor for scattering angle errors as a retrieved inversion parameter. The inversion technique is validated by numerical simulations and applied to field data. It is shown that ground-based sunphotometer measurements enable one to derive the real part of the aerosol refractive index with an absolute error of 0.03–0.05 and to distinguish roughly between weakly and strongly absorbing aerosols. The aureole angular observation scheme can be refined with an absolute accuracy of 0.15–0.19 deg. Offset corrections to the scattering angle error are generally found to be small and consistently of the order of -0.17. This error magnitude is deduced to be due primarily to nonlinear field-of-view averaging effects rather than to instrumental errors.

© 1999 Optical Society of America

Retrieval of the scattering and microphysical properties of aerosols from ground-based optical measurements including polarization. I. Method

Anne Vermeulen, Claude Devaux, and Maurice Herman
Appl. Opt. 39(33) 6207-6220 (2000)

Optical properties and size distribution of aerosols derived from simultaneous measurements with lidar, a sunphotometer, and an aureolemeter

Tadahiro Hayasaka, Yasuhiko Meguro, Yasuhiro Sasano, and Tamio Takamura
Appl. Opt. 38(9) 1630-1635 (1999)

Experimental validation of the solar aureole technique for determining aerosol size distributions

A. Deepak, G. P. Box, and M. A. Box
Appl. Opt. 21(12) 2236-2243 (1982)

Atmospheric Aerosol Index of Refraction and Size-Altitude Distribution from Bistatic Laser Scattering and Solar Aureole Measurements

Gray Ward, K. M. Cushing, R. D. McPeters, and A. E. S. Green
Appl. Opt. 12(11) 2585-2592 (1973)

Retrieval and monitoring of aerosol optical thickness over an urban area by spaceborne and ground-based remote sensing

Jean-François Léon, Patrick Chazette, and François Dulac
Appl. Opt. 38(33) 6918-6926 (1999)