The Hemispheric Reflectance of a Plane Water Surface for Atmospheric Radiation

The hemispheric reflectance of a plane water surface is computed for clear sky and low overcast sky emission spectra. The gross features of clear sky emission are described by a model that has a deficiency of emission in the 8–13 μm band. The deficiency is most pronounced in the zenith but disappears as the zenith angle approaches the horizon. The radiation from a low overcast sky is assumed to be blackbody. The computation is made using Fresnel formulae for a conducting medium. The hemispheric reflectance for clear sky radiation is found to be approximately 0.018 higher than the overcast (blackbody) value, which ranged from 0.113 to 0.107 for atmospheric temperatures ranging from 273 to 313K, respectively.