ESTIMATION OF MEASUREMENT ERROR OF THE SEAWATER BEAM ATTENUATION COEFFICIENT IN TURBID WATER OF ARCTIC SEAS

The article describes the estimation of measurement error of seawater beam attenuation coefficient using the Monte Carlo method. Measurements of the beam attenuation coefficient and its vertical distribution are the most common type of hydro-optical investigations since it is widely used for the research of light distribution in sea medium. Moreover, the beam attenuation coefficient is closely related to the concentration of the suspended substance and may be used for its estimation. Usually, the measurements of beam attenuation coefficient are conducted with small instrument base in rather transparent waters. In this case, the method errors of the beam attenuation coefficient measurement are low. However, in practice, cases of very turbid waters (near-bottom nepheloid layers), where measurement errors of beam attenuation coefficient significantly increase due to multiple scattering within the instrument base, are often encountered. The estimation of such errors is reviewed in this work. The effect of scattering phase function on the considered errors is described to the greatest extent. Moreover, the effect of the instrument base length and angle of view of the receiving system on measurement errors of beam attenuation coefficient is studied. Corresponding estimations are provided.