Retrieval of aerosol single-scattering albedo from ground-based measurements: Application to observational data

The single-scattering albedo ω0 of atmospheric aerosols is a key parameter concerning the effect of the particles on the Earth's radiative budget. Retrieval of this parameter from in situ measurements is a difficult task. We address the possibility to derive ω0 from ground-based measurements of solar transmission and diffuse skylight, independent of the knowledge of the aerosol properties or the absorption mechanism. The proposed method is based on the normalization of the aerosol phase function that is derived from scannings of the skylight. The method has been applied to a series of observations conducted during a few years over the french site of La Crau, near the industrial area of Fos sur Mer in the southeast of France. The aerosol albedo, retrieved near the 870 nm wavelength, ranges from 0.60 to 0.95. The estimated error is Δω0 ≈ ±0.05. To test their reliability, the retrieved ω0 have been used to calculate the diffuse/total solar fluxes at ground level. These estimates are consistent within about 10% with independent direct/diffuse flux measurements performed simultaneously.