Optical properties of the clearest natural waters (200-800nm)

A new UV submersible spectroradiometer has been employed to determine the diffuse attenuation coefficient for irradiance in the clearest natural waters K_w(\lambda) with emphasis on the spectral region from 300 to 400 nm. K_w(\lambda) can be related to the inherent optical properties of pure water in particular the total absorption coefficient a_w(\lambda) and the molecular scattering coefficient b_m(\lambda), by means of equations derived from radiative transfer theory. The authors present an analysis showing that limiting values of K_w(\lambda) can be estimated from a_w(\lambda) and vice versa. Published a_w(\lambda) dat, which show discrepancies much larger than their estimated accuracies, are briefly reviewed and then compared, via the authors' analysis, with K_w(\lambda) data the authors' own new and previously published data as well as relevant data of others). This comparative analysis and new data allow a consistent and accurate set of optical properties for the clearest natural waters and for pure fresh water and saltwater to be estimated from 300 to 800 nm.

R. C. Smith, K. S. Baker, "Optical properties of the clearest natural waters (200-800 nm)," Appl. Opt.,20, 177-184 (1981).