Spectral in-water measurements of downward irradiance (Ed), upward irradiance (Eu), and nadir radiance (Lu) are sufficient to calculate the scalar irradiances E0, E0d, and E0u, the average cosines μ, μd, and μu, the light absorption coefficient a, the backscattering coefficient bb, and the so-called f factor that relates to R, a, and bb. The solar elevation of 42° is a special case in which μd is independent of all variables except solar elevation. The algorithms are valid for solar elevations between 12° and 81° for horizontally stratified clear and turbid deep waters.
© 2001 Optical Society of America
Niels Kristian Højerslev, "Analytic Remote-Sensing Optical Algorithms Requiring Simple and Practical Field Parameter Inputs," Appl. Opt. 40, 4870-4874 (2001)