Absorption of light by water in the region of high transparency: recommended values for photon-transport calculations

Prompted by data requirements for photon-transport simulation, we have surveyed measurements of the absorption coefficient of light by water in the wavelength range 171-2000 nm, covering the whole region where the absorption length exceeds 1 mm. Absorption spectra were compiled for pure water, clean seawater, and seawater containing a moderate amount of organic matter. The intensive and detailed nature of the laboratory and at-sea observations leading to the pure-water and clean-seawater spectra lend confidence to these results. As to dissolved organic matter in seawater, this is so highly variable in composition and concentration that this spectrum can only be considered as indicative of its effects.