Frost Risk Budbreak Date Estimate

Locate caller heat-sum budbreak proxy then audit observed subsequent frost, not a repeat GDD accumulator or validated phenology/damage forecast; start/reset and heat calibration must be independently established.

Description

A heat-sum model can mark a budbreak proxy within observed weather.

A heat-sum model can mark a budbreak proxy within observed weather. Frost after that point is a separate observed exposure.

When to use Frost Risk Budbreak Date Estimate

Use this tool to locate caller heat-sum budbreak proxy then audit observed subsequent frost, not a repeat GDD accumulator or validated phenology/damage forecast; start/reset and heat calibration must be independently established.

Prepare vineyard measurements, dates or block records for the intended growing period. Keep weights, counts and weather observations in the stated units.

How to use Frost Risk Budbreak Date Estimate and understand its results

Prepare vineyard measurements, dates or block records for the intended growing period. Keep weights, counts and weather observations in the stated units.
Enter dailyMeanTemperaturesC, dailyMinimumTemperaturesC, callerBudbreakHeatBaseC, callerBudbreakHeatSumCelsiusDays, callerPostBudbreakFrostThresholdC using the field table and calculation rules, then run the tool.
Read callerModelBudbreakFound, callerModelBudbreakDayIndex, observedPostModelBudbreakFrostIndices. 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
dailyMeanTemperaturesC	Daily mean temperatures c	list of number	Required
dailyMinimumTemperaturesC	Daily minimum temperatures c	list of number	Required
callerBudbreakHeatBaseC	Caller budbreak heat base c	number	Required
callerBudbreakHeatSumCelsiusDays	Caller budbreak heat sum celsius days	number	Required
callerPostBudbreakFrostThresholdC	Caller post budbreak frost threshold c	number	Required

Align daily means and minima, requiring minima no greater than means. Use a positive heat target; locate its first crossing and include that day's minimum in the frost audit. Return −1 and an empty frost list if no crossing occurs.^[1]

Paired lists must be nonempty and have equal lengths.

heat sum = Σ max(0,daily mean − base); first crossing ≥ target

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

Output field	Meaning	Value type
callerModelBudbreakFound	Caller model budbreak found	boolean
callerModelBudbreakDayIndex	Caller model budbreak day index	number
observedPostModelBudbreakFrostIndices	Observed post model budbreak frost indices	list of number

json

{
  "input": {
    "dailyMeanTemperaturesC": [
      0,
      10,
      10,
      10
    ],
    "dailyMinimumTemperaturesC": [
      0,
      0,
      -1,
      1
    ],
    "callerBudbreakHeatBaseC": 5,
    "callerBudbreakHeatSumCelsiusDays": 10,
    "callerPostBudbreakFrostThresholdC": 0
  },
  "output": {
    "callerModelBudbreakFound": true,
    "callerModelBudbreakDayIndex": 2,
    "observedPostModelBudbreakFrostIndices": [
      2
    ]
  }
}

Limitations and assumptions

Start/reset and phenology calibration are supplied; this is not a damage forecast.

Numbers and computed results must be finite; overflow 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. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Heat Wave Shriveling Risk Days: Count caller heat-wave duration policy on observed maximum temperatures; not baseline-percentile WSDI, measured berry water loss or shriveling/damage diagnosis. For a complementary task, use Veraison To Harvest Day Span: Audit observed veraison/harvest event timeline on caller continuous day ordinals, preserving no harvest as right-censored duration; no maturity-optimum date or fixed variety calendar.

References

Frost Risk Budbreak Date Estimate — tool.io

Similar or alternative tools

Heat Wave Shriveling Risk Days
Count caller heat-wave duration policy on observed maximum temperatures; not baseline-percentile WSDI, measured berry water loss or shriveling/damage diagnosis.
Veraison To Harvest Day Span
Audit observed veraison/harvest event timeline on caller continuous day ordinals, preserving no harvest as right-censored duration; no maturity-optimum date or fixed variety calendar.