Scripps Institution of Oceanography

The asymptotic radiance hypothesis asserts that the angular distribution of radiance approaches a fixed form st great depths in natural waters. A simple proof of this hypothesis is given, and consequences deduced. Further consequences are that the classical Schuster two-flow equations for the light field in natural waters become exact with increasing depth. These and related results are illustrated by examples drawn from the special case of isotropic scattering. Finally, a formula is given which allows an estimate of the depth at and below which the actual radiance distributions differ from the asymptotic distribution by no more than a preassigned amount.