| Резюме: | Water clarity, defined in this study using measurements of the downwelling diffuse light attenuation coefficient (K<sub>d</sub>) and turbidity, is an important indicator of lake trophic status and ecosystem health. We used in-situ measurements to evaluate existing semi-analytical models for K<sub>d</sub> and turbidity, developed a regional turbidity model based on spectral shape, and evaluated the spatial and temporal trends in Lake Washington from 2013 to 2022 using Landsat-8/9 Operational Land Imager (OLI). We found no significant trends from 2013 to 2022 in K<sub>d</sub> or turbidity when both the annual and full datasets were considered. In addition to the spring peak lasting from April through June, autumn K<sub>d</sub> peaks were present at all sites, a pattern consistent with seasonal chlorophyll <i>a</i> and zooplankton concentrations. There existed no autumn peak in the monthly turbidity dataset, and the spring peak occurred two months before the K<sub>d</sub> peak, nearly mirroring seasonal variability in the Cedar River discharge rates over the same period. The K<sub>d</sub> and turbidity algorithms were thus each more sensitive to different sources of water clarity variability in Lake Washington.
|
|---|