Daily Light Integral MOL M2 Day

Integrate measured time-varying PPFD by trapezoids into observed daily photon dose; unobserved hours are not silently filled and a constant PPFD-to-DLI alias is excluded.

Description

Daily light integral accumulates photosynthetic photon flux density over time.

Daily light integral accumulates photosynthetic photon flux density over time. A partial observation window represents only its observed dose, not an automatically completed 24-hour day.^{[1, 2]}

Integrate measured time-varying PPFD by trapezoids into observed daily photon dose; unobserved hours are not silently filled and a constant PPFD-to-DLI alias is excluded.

When to use Daily Light Integral MOL M2 Day

Use this tool to integrate measured time-varying PPFD by trapezoids into observed daily photon dose; unobserved hours are not silently filled and a constant PPFD-to-DLI alias is excluded.

Prepare the plant, nutrient, light or scheduling measurements for the intended crop and period. Keep paired records aligned and confirm units and supplied target values.

How to use Daily Light Integral MOL M2 Day and understand its results

Prepare the plant, nutrient, light or scheduling measurements for the intended crop and period. Keep paired records aligned and confirm units and supplied target values.
Enter sampleTimesHours, ppfdMicromolesPerM2Second using the field table and calculation rules, then run the tool.
Read observedLightIntegralMolPerM2, observationDurationHours, meanPpfdMicromolesPerM2Second. 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
sampleTimesHours	Sample times hours	list of number	Required
ppfdMicromolesPerM2Second	Ppfd micromoles per m2 second	list of number	Required

Use at least two increasing sample hours and aligned nonnegative PPFD in μmol/m²/s, spanning no more than 24 hours. Return integrated moles/m², window duration and time-mean PPFD.

Paired lists must be nonempty and have equal lengths.

observed dose mol/m²=0.0036 × trapezoidal integral of PPFD over hours

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

Output field	Meaning	Value type
observedLightIntegralMolPerM2	Observed light integral mol per m2	number
observationDurationHours	Observation duration hours	number
meanPpfdMicromolesPerM2Second	Mean ppfd micromoles per m2 second	number

json

{
  "input": {
    "sampleTimesHours": [
      0,
      1,
      2
    ],
    "ppfdMicromolesPerM2Second": [
      0,
      100,
      0
    ]
  },
  "output": {
    "observedLightIntegralMolPerM2": 0.36,
    "observationDurationHours": 2,
    "meanPpfdMicromolesPerM2Second": 50
  }
}

Limitations and assumptions

No missing hours are filled and the tool does not supply a crop light target.

Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Supplemental Light Shortfall Hours: Invert measured natural-light deficit into supplementary hours with delivery loss and a caller available photoperiod; unmet photon budget is explicit, not a crop lighting recommendation. For a complementary task, use Light Uniformity Grid Checker: Audit measured light-grid population variability and minimum/mean plus low-light area using physical cell weights; no lamp-layout optimization or universal crop threshold.

Further background: Measuring daily light integral in a greenhouse.

References

Daily Light Integral MOL M2 Day — tool.io
Measuring daily light integral in a greenhouse — Purdue Extension

Similar or alternative tools

Supplemental Light Shortfall Hours
Invert measured natural-light deficit into supplementary hours with delivery loss and a caller available photoperiod; unmet photon budget is explicit, not a crop lighting recommendation.
Light Uniformity Grid Checker
Audit measured light-grid population variability and minimum/mean plus low-light area using physical cell weights; no lamp-layout optimization or universal crop threshold.