Sensitivity of radiative transfer to small-angle scattering in the ocean: Quantitative assessment.

It is shown that measurements of the absorption coefficient and the volume-scattering function for scattering angles ? 15° of ocean water are sufficient for predicting the transport of irradiance in the ocean. Thus, difficult-to-measure small-angle scattering is not necessary in many applications. Furthermore, the irrelevance of small-angle scattering suggests the irrelevance of the scattering coefficient and of the routinely measured beam-attenuation coefficient in many radiative-transfer problems. Finally, these observations provide a method for determining the adequacy of instruments in which small sampling volumes (~ few cm(3)) are analyzed when predicting irradiance attenuation and diffuse reflection for large volumes (~ 10-10(4) M(3)).