Multiple Scattering of Polarized Light in Planetary Atmospheres Part II. Sunlight Reflected by Terrestrial Water Clouds

Abstract The intensity and polarization of sunlight reflected by terrestrial water clouds are computed with the doubling method. The calculations illustrate that this method can be effectively used in problem involving strongly anisotropic phase matrices. The method can therefore be used to derive information about planetary clouds, including those of the earth, from polarimetric observations. The results of the computations indicate that the polarization is more sensitive than the intensity to cloud microstructure, such as the particle size and shape. Multiple scattering does not wash out features in the polarization as effectively as it does in the intensity, because the polarization arises primarily from photons scattered once or a small number of times. Hence polarization measurements, particularly in the near infrared, are potentially a valuable tool for cloud identification and for studies of the microphysics of clouds. The computations are made primarily at four wavelengths in the near infrared, fr...