Radiative properties of terrestrial clouds at visible and infra‐red thermal window wavelengths

Abstract A detailed theoretical study of the radiative properties of water droplet and ice clouds at visible and infra‐red wavelengths of 2·3, 3·5, 3·8 and 8·5 and 11 μm is presented. The radiative transfer computations have used a model atmosphere in which the microphysical properties of the clouds have been accurately incorporated. A range of physically realistic size distributions for the cloud particles have been used. The results have been presented in the form of tables of the emissivity, reflectivity and transmissivity, and their equivalent fluxes, at a particular wavelength, as a function of the optical thickness of the cloud layer. A simple scaling relationship enables these extensive tables to be used for any water content of the cloud layers. The results provide a detailed understanding of the radiative properties of terrestrial clouds at thermal infra‐red window wavelengths. The theoretical results are used to interpret infra‐red observations of stratocumulus and cirrus clouds.