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A simple water clarity-turbidity index for marine and inland waters: Great Lakes case study
  • Guangming Zheng,
  • Paul DiGiacomo
Guangming Zheng
National Oceanic and Atmospheric Administration (NOAA)

Corresponding Author:guangming.zheng@noaa.gov

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Paul DiGiacomo
NOAA, Mar. Ecosystems and Climate Branch
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There are a plethora of satellite-derived water clarity and turbidity indicators to support the decision making of environmental managers and policy makers. However, water quality dynamic ranges addressed by these indicators can differ significantly, subjecting unsuspecting users to potential pitfalls. Here we propose a satellite water clarity-turbidity index (CTI) as a simplified way to capture major changes in water clarity/turbidity across all water types. This is achieved by merging three satellite-derived indicators, namely, the Secchi disk depth, the particulate backscattering coefficient, and the nephelometric turbidity, which are suitable for clear, intermediate, and turbid waters, respectively. Application to the Great Lakes shows that with one parameter, the CTI can illustrate major spatial and temporal patterns that are not entirely visible with each of the three original indicators alone, making it a convenient holistic assessment tool for water quality management.