Optical Cloud Characteristics Derived from Measurements of Reflected or Transmitted Solar Radiation

An extended and horizontally homogeneous cloud of a large optical thickness and a weak absorption compared with scattering is considered. The strict analytical formulas for determination of a single-scattering albedo and an optical thickness of this cloud are derived from the strict solution of the radiation transfer equation. These formulas allow retrieving the optical cloud parameters from the reflected or transmitted spectral radiation measurements. A detailed error analysis of the proposed method is carried out. The obtained formulas are applied to the ground-based spectral measurements of the transmitted radiance. The spectral values of the single-scattering albedo and the optical thickness are obtained.