On the Instrument for Measuring Angular Distribution of Underwater Radiance

The positively phototactic reaction of daphnia magna straus: A contribution to the understanding of diurnal vertical migration

“…that there are large differences in light intensity between 30°-60 ° with the vertical. These angular changes in light intensity may be so large that relatively sharp contrasts are present, as might be deduced from data furnished by SASAKI et al (1962) or WHITNEY (1940. The exact angular position of the contrasts varies with the altitude of the sun and the direction of the plane of measurement with respect to the sun.…”

“…With increasing depth these contrasts fade away to intensity gradients (see fig. 8 and 9 in the paper of SASAKI et al, 1962).…”

Movements of blue sharks (Prionace glauca) in depth and course

“…1) remained below 50 m almost all night but followed a smooth course during this time. The angular dispersion of radiance increases with depth so that the submarine light-field becomes broadly vertical (Sasaki 1964) and the sun becomes a less effective compass. It seems likely that an orientation principle other than celestial cues must be employed to maintain a steady course at depth and during the night.…”

Bidirectional reflectance function for oceanic waters with varying chlorophyll concentrations: Measurements versus predictions

“…Notwithstanding that multiple scattering occurs within the medium and thus tends to homogenize the radiant field, the polar and azimuthal asymmetries persist throughout the upper layers of the ocean. The experimental evidence of this phenomenon dates back to the end of the 1950s and 1960s (Jerlov and Fukuda 1960;Tyler 1960;Sasaki et al 1962); yet, the theoretical analysis and modeling of the upwelling light field has been undertaken more recently (Morel and Gentili 1991, 1993, 1996. The quantitative study of this anisotropy, essentially based on theory and computations, has been prompted by the implication of this phenomenon in the ocean color remote sensing problem, in so far as the radiance emerging from the ocean depends on the bidirectional structure of the upward radiance field just beneath the interface.…”