Influence of Wind Currents on Spectral Light Attenuation in Water

Abstract

The paper deals with wind current dependences of spectral light attenuation measured in natural waters of lakes in the south of West Siberia. To reveal the significance of abiotic, i.e., physical factors affecting water transparency, we calculate relative spectral contributions of individual optically active water components in freshwater lakes established during hydrophysical research of 2019. In addition, the published data on the daily dynamics of spectral water transparency obtained by researchers of IWEP SB RAS for Lake Krasilovskoye in 2016 are partially analyzed. The greatest spectral contribution to the total light attenuation falls on suspension consisting mainly of phytoplankton algae particles and yellow matter. Wind current velocity is a determining factor affecting light attenuation dynamics because the upward redistribution of particle concentration in upper layers of the lake caused by wind-induced turbulent mixing occurs faster than the change in the yellow matter content as a result of physical-chemical processes responsible for its formation. In such cases, the intensity of turbulence (turbulent mass exchange) is usually characterized by flow (integral) Richardson number Ri, which is directly dependent on wind current velocity. In our experiment, Ri equals to 1.5.