TSI Carlson Secchi Calculator
Apply Carlson Secchi TSI using observed meters; empirical clarity index may be confounded by nonalgal turbidity.
Description
Secchi depth describes observed clarity.
When to use TSI Carlson Secchi Calculator
Use TSI Carlson Secchi Calculator when you need to evaluate the supplied records under the calculation and evidence rules below. Nonalgal turbidity and color can confound the relationship with algal biomass. No water-quality certification is provided.
Prepare the observed lake or sample measurements and explicit calibration, reference values or thresholds requested. Keep depth coverage, units, dates and sampling conditions consistent.
How to use TSI Carlson Secchi Calculator and understand its results
- Prepare the observed lake or sample measurements and explicit calibration, reference values or thresholds requested. Keep depth coverage, units, dates and sampling conditions consistent.
- Enter secchiDepthM using the field table and calculation rules, then run the tool.
- Read carlsonTrophicStateIndex. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| secchiDepthM | Secchi depth m | number | Required |
Enter strictly positive observed depth in meters. Apply the natural logarithm and return an unclipped finite index.
TSI=60−14.41ln(SecchiDepthMeters) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| carlsonTrophicStateIndex | Carlson trophic state index | number |
{
"input": {
"secchiDepthM": 1
},
"output": {
"carlsonTrophicStateIndex": 60
}
}Limitations and assumptions
Nonalgal turbidity and color can confound the relationship with algal biomass. No water-quality certification is provided.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Secchi Depth Transparency Recorder: Secchi disappearance and reappearance readings define paired clarity estimates. Reaching the lake bottom censors the observation. For a complementary task, use TSI Carlson Chlorophyll Calculator: Chlorophyll is an algal-pigment proxy. Carlson’s empirical index relates its concentration to a continuous trophic-state scale.
Further background: Carlson Trophic State Equations and Interpretation.
References
-
TSI Carlson Secchi Calculator — tool.io
-
Carlson Trophic State Equations and Interpretation — North American Lake Management Society
Similar or alternative tools
- Secchi Depth Transparency Recorder
Secchi disappearance and reappearance readings define paired clarity estimates. Reaching the lake bottom censors the observation.
- TSI Carlson Chlorophyll Calculator
Chlorophyll is an algal-pigment proxy. Carlson’s empirical index relates its concentration to a continuous trophic-state scale.