Visibility Of The Sea With Special Reference To The Secchi Disc

A general visibility theory valid in inhomogeneous hydrosols is presented and experimentally verified for some special cases. The field measurements used in the experimental verification were obtained from both oligotrophic and eutrophic regions in the sea and comprise of a fairly large Danish and French data set consisting of spectral downward and upward irradiances, downward quanta irradiance, spectral light transmission, spectral radiance distributions and finally, spectral Secchi disc measurements.