Trends in spatial and temporal variability of optical properties in western Lake Erie

Session: Remote Sensing, Visualization, and Spatial Data Applications for the Great Lakes (2)

Mike Sayers, Michigan Tech. Research Inst., [email protected]
Karl Bosse, Michigan Tech Research Inst., [email protected]
Robert Shuchman, Michigan Technological University, [email protected]
Steve Ruberg, NOAA - GLERL, [email protected]
Gary Fahnenstiel, Great Lakes Res Center/ Mich Tech Res Institute, Michigan Technological Univ, [email protected]
George Leshkevich, Great Lakes Env. Research Lab, NOAA, [email protected]
Dack Stuart, CIGLR, University of Michigan, [email protected]
Thomas Johengen, CILER, University of Michigan, [email protected]

Abstract

Lake Erie has experienced dramatic changes in water quality over the past several decades requiring extensive monitoring activities to assess effectiveness of adaptive management strategies. Remote sensing offers a unique potential to provide synoptic monitoring at daily time scales complementing ongoing in-situ sampling activities in Lake Erie. Bio-optical remote sensing algorithms require knowledge about the inherent optical properties (IOPs) of the water for parameterization to produce robust products. This study reports a new IOP dataset for western Lake Erie that encapsulates the May-October period for 2015 and 2016 at weekly sampling intervals. Previously reported IOP observations have been limited in temporal range and have not assessed statistical differences between IOP variables over spatial and temporal gradients. The objective of this study is to assess trends in IOPs over variable spatial and temporal scales.   Large spatio-temporal variability in IOPs were observed between 2015 and 2016 likely due to the difference in the extent and duration of mid-summer cyanobacteria blooms. Differences in the seasonal trends of the phytoplankton absorption coefficient between 2015 and 2016 suggest differing algal assemblages between the two years. Other IOP variables including CDOM and beam attenuation spectral slopes suggest variability is influenced by river discharge and sediment re-suspension.