A Study on Spectra of Backscattered Light from the Water's Surface as a Water Qualty Indicator

In order to assess the coastal environment and to monitor water pollution from the air, it is necessary to clarify the relationship between spectral response of natural water and the water's quality. For a two year period from 1975 to 1977, studies of observation of transparency and spectral reflectivity from the water's surface were carried out on several lakes in Japan and in the sea around Japan by the authors.Water samples were also taken during this time. The sampled water was analyzed quantitatively regarding items of optical water quality such as suspended solids and chlorophyll concentrations.In this paper, the relationship between spectral responses from the water's surface and the water's quality, which were deduced through our observations, are discussed. As the polluted water had a higher spectral response than clear water, it was concluded that observation of spectra of backscat-tered light from the water's surface is a useful indicator of water quality.