RETRIEVAL OF AEROSOL SINGLE-SCATTERING ALBEDO FROM GROUND-BASED MEASUREMENTS - APPLICATION TO OBSERVATIONAL DATA

The single-scattering albedo omega(0) of atmospheric aerosols is a key parameter concerning the effect of the particles on the Earth's radia tive budget. Retrieval of this parameter from in situ measurements is a difficult task. We address the possibility to derive omega(0) from g round-based measurements of solar transmission and diffuse skylight, i ndependent of the knowledge of the aerosol properties or the absorptio n 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 dur ing a few years over the french site of La Crau, near the industrial a rea of Fos sur Mer in the southeast of France. The aerosol albedo, ret rieved near the 870 nm wavelength, ranges from 0.60 to 0.95. The estim ated error is Delta omega(0) approximate to +/-0.05. To test their rel iability, the retrieved omega(0) have been used to calculate the diffu se/total solar fluxes at ground level. These estimates are consistent within about 10% with independent direct/diffuse flux measurements per formed simultaneously.