Seasonal Patterns of Lake Michigan Inherent Optical Properties with Implications for Remote Sensing

Session: 61. - Remote Sensing, Visualization, and Spatial Data Applications for the Great Lakes

Mike Sayers, Michigan Tech. Research Inst., [email protected]
Steve Ruberg, NOAA - GLERL, [email protected]
George Leshkevich, Great Lakes Env. Research Lab, NOAA, [email protected]
Karl Bosse, Michigan Tech Research Inst., [email protected]
Dack Stuart, CIGLR, University of Michigan, [email protected]
Robert Shuchman, Michigan Technological University, [email protected]

Abstract

Monthly measurements of inherent optical properties (IOPs) were made by NOAA/GLERL and MTRI at three sites in Lake Michigan offshore of Muskegon, MI from approximately April through October in 2015, 2016, and 2017. Water column IOP measurements of absorption, beam attenuation, and the volume scattering function were made using a WetLabs AC-S and BB-9 respectively.  A Satlantic hyperspectral profiling radiometer was deployed to measure water column reflectance and diffuse attenuation.  Water column profiles Phytoplankton composition were periodically measured with a bbe FluoroProbe. Coincident water samples were collected and analyzed for concentrations of chlorophyll, TSM, and CDOM absorption.  These suites of measurements are invaluable for the calibration and validation of remote sensing water quality algorithms. The objective of collecting these time-series observations is to document the temporal variations in IOPs due to shifts in phytoplankton composition and nearshore processes. Significant differences in absorption spectra were observed throughout the observation period and between years.  These observed differences are attributed to fluctuations in phytoplankton composition and concentration but also from the periodic occurrence of CDOM and sediment laden plumes from the Muskegon River.  These newly collected data will be compared to historical measurements to assess temporal changes in Lake Michigan’s underwater light field.

1. Keyword
remote sensing

2. Keyword
Lake Michigan

3. Keyword
phytoplankton

4. Additional Keyword
Optics