Infrared polarization in the natural Earth environment

This paper provides a summary of research undertaken to quantify the degree of polarization that occurs in thermal infrared radiance in the natural Earth environment. Water surfaces provide one of the only significantly polarized natural sources of thermal infrared radiation, while emission from the atmosphere and ground is almost always unpolarized to any practical degree. However, the actual degree of polarization from water depends upon a balance of orthogonally polarized emission and background reflection terms, weighted by atmospheric transmittance. This summary describes computer simulations of polarized radiance from water viewed in a realistic atmosphere and a comparison of the model with measurements of the spectral degree of thermal infrared polarization for water.