Two-stream irradiance model for deep waters.

The two-stream model expresses the vertical attenuation coefficient K and the irradiance ratio R as functions of the absorption coefficient a, the backward scattering coefficient b(b), the downward and upward average cosines micro (d) and micro (u), and the normalized reflectance coefficients of downward and upward scalar irradiance, r(d) and r(u). While K/a and R are almost linear functions of b(b)/a when b(b)/a is small, they will approach asymptotic values, which only depend on r(d), r(u), micro (d), and micro (u) when b(b)/a becomes large. The results agree well with oceanic observations of K and R. They also agree with theoretical results derived by other methods. Still proper testing of the model in turbid waters remains.