Secchi Depth Transparency Recorder

Record actual paired Secchi disappearance/reappearance with disagreement uncertainty, rejecting bottom-censored readings rather than calling them measured transparency.

Description

Secchi disappearance and reappearance readings define paired clarity estimates.

Secchi disappearance and reappearance readings define paired clarity estimates. Reaching the lake bottom censors the observation.^[1]

Enter aligned nonempty nonnegative depths and positive bottom depth. Require every reading strictly shallower than bottom; return pairs, their mean and half differences.

When to use Secchi Depth Transparency Recorder

Use Secchi Depth Transparency Recorder when you need to evaluate the supplied records under the calculation and evidence rules below. The half difference is a paired-reading disagreement measure, not complete statistical uncertainty. No bottom-censored value is accepted as measured transparency.

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 Secchi Depth Transparency Recorder 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 disappearanceDepthsM, reappearanceDepthsM, lakeBottomDepthM using the field table and calculation rules, then run the tool.
Read pairedSecchiDepthsM, meanObservedSecchiDepthM, halfDifferenceUncertaintiesM. 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
disappearanceDepthsM	Disappearance depths m	list of number	Required
reappearanceDepthsM	Reappearance depths m	list of number	Required
lakeBottomDepthM	Lake bottom depth m	number	Required

Enter aligned nonempty nonnegative depths and positive bottom depth. Require every reading strictly shallower than bottom; return pairs, their mean and half differences.

paired=(disappearance+reappearance)/2; halfDifference=abs(disappearance−reappearance)/2

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
pairedSecchiDepthsM	Paired secchi depths m	list of number
meanObservedSecchiDepthM	Mean observed secchi depth m	number
halfDifferenceUncertaintiesM	Half difference uncertainties m	list of number

json

{
  "input": {
    "disappearanceDepthsM": [
      1,
      2
    ],
    "reappearanceDepthsM": [
      1.2,
      2.2
    ],
    "lakeBottomDepthM": 3
  },
  "output": {
    "pairedSecchiDepthsM": [
      1.1,
      2.1
    ],
    "meanObservedSecchiDepthM": 1.6,
    "halfDifferenceUncertaintiesM": [
      0.09999999999999998,
      0.10000000000000009
    ]
  }
}

Limitations and assumptions

The half difference is a paired-reading disagreement measure, not complete statistical uncertainty. No bottom-censored value is accepted as measured transparency.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use TSI Carlson Secchi Calculator: Secchi depth describes observed clarity. Carlson’s logarithmic transformation places it on an empirical trophic-state scale. For a complementary task, use Euphotic Zone Depth From Secchi Calculator: Secchi-based euphotic depth uses a caller’s local multiplier. An estimate beyond bottom should remain visible as a modeled value.

References

Secchi Depth Transparency Recorder — tool.io

Similar or alternative tools

TSI Carlson Secchi Calculator
Secchi depth describes observed clarity. Carlson’s logarithmic transformation places it on an empirical trophic-state scale.
Euphotic Zone Depth From Secchi Calculator
Secchi-based euphotic depth uses a caller’s local multiplier. An estimate beyond bottom should remain visible as a modeled value.