A simple water clarity-turbidity index for marine and inland waters:
Great Lakes case study
Abstract
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.