Experimental and theoretical studies on visible light attenuation in water

TL;DR

This paper combines laboratory experiments and theoretical modeling to measure how visible light attenuates in freshwater, providing spectral attenuation data and validating models against existing literature.

Contribution

It introduces a novel experimental setup and modeling approach for determining spectral water attenuation coefficients in freshwater environments.

Findings

Spectral distribution of attenuation coefficient obtained for freshwater.

Model results align with existing literature data.

Preliminary calibration established for future detailed studies.

Abstract

In this study we describe lab experiments on determining the above water reflectance Rrs coefficient, and the water attenuation coefficient Kd for fresh water. Different types of screens (totally absorbent, gray, etc.) were submerged in water (0-0.6 m) and illuminated from outside. The spectral density of the water leaving radiance was measured for different depths. The results were ran by a code which took into account the geometry of the incident irradiation, the geometry of the screen under water, and boundary conditions at the water surface provided by the radiation transfer theory. From the experimental data and our model we obtain the spectral distribution of the attenuation coefficient for fresh water and compared it with other data in literature. These experiments, performed in the Nonlinear Wave Lab at ERAU# represent just a preliminary calibration of the experimental protocol. More tests with water of different degrees of turbidity, and possibly wave filed at the water surface are in progress and will be presented in a forthcoming paper.