<title>Optical properties of pure water</title>

Abstract

The optical properties of pure water are basic input data for many geophysical investigations such as remote sensing of surface water and underwater radiative transfer calculations. Knowledge of the spectral properties of components in surface water is required for accurate interpretation of measured reflection and attenuation spectra in terms of their concentrations. Also the sources and sizes of errors in the basic data must be known. Absorption measurements were done with a submersible absorption meter in the temperature range 2.5 till 40.5 degree(s)C. The scattering of pure water is recalculated using the Einstein-Smoluchowski equation. The input for this equation is evaluated and the temperature dependency is included. New values for the absorption coefficient are given based on these results and analysis of data from the literature. Absorption in the wavelength range 300 - 550 nm is lower than presently used values. In the wavelength range about 700 nm the spectrum has a different shape. A formulation of the effect of temperature on the absorption spectrum is given.