The Polarization of the Near

Submitted to the Department of Geology and Geophysics on July 26, 1966 in partial fulfillment of the requirement for the degree of Doctor of Philosophy. The underwater light field exhibits large spatial and temporal irregularities near the surface, but as the depth is increased to the near asymptotic region the behavior becomes regular and predictable. The horizontal light field at near asymptotic depths shows a marked degree of polarization. This polarization is due to the unsymmetrical shape of the submarine light field and the scattering of the penetrating light from the sea water suspensoid. In an effort to provide an approximation of the degree of polarization a numerical method was devised to solve the vector equations of invariant embedding in a medium with absorption and anisotropic scattering. The method uses the modified Stokes parameters to describe the sinking light field, and the scattering properties of the medium are characterized by Mueller matrices. Calculations using this method indicate that the near asymptotic polarization should lie in the vicinity of 18%. In order to evaluate the Mueller scattering matrix for sea water samples, am existing light scattering photometer was modified and recalibrated. Measurements made on deck with the modified scattering matrix photometer on a variety of samples show that the inherent polarizatioa due to a single scattering from a small contained sample is near zero in the forward region, rises to a maximum of 30 70 near a scattering angle of 90 , and them decays to zero as the scattering angle is further increased. Thesis Supervisor: henry G. Houghten Vitle: Professor of Meteorology