Analysis of Uncertainties Associated to Underwater Hyperspectral Attenuation Measurements.

Abstract

The uncertainty for the underwater hyperspectral measurement of attenuation (ACS) is studied. The attenuation measurements for standard particles of different diameters (2,5,10,20 mm) by ultra violet visible (UV-Vis) spectrophotometer (PE35) are compared with model values by Mie scattering theory, and the attenuation measurement error of PE35 is found less than 8% . Subsequently, simultaneous atlenuation measurements by ACS and PE35 are carried out for samples from the high turbid water in the East China Sea. Comparative results show the attenuation measurements by ACS are underestimated in high turbid water, and the uncertainty of ACS measurements has a negative correlation with wavelength, conversely, with a strong positive correlation with turbidity of water. The attenuation measurements of ACS(10 cm) and ACS(25 cm) are underestimated within 17.2% ~19.04% and 7.84% ~15.36% in low turbid water, respectively, while ACS(10 cm) is within 26.4%~28.24% in high turbid water.