Geology Dendrochronology Ring Width Index Calculator
Measured/independently detrended expected ring-width indices, not invented detrending model or raw crossdating correlations. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.
Description
A ring-width index compares an observed growth measurement with an independently established expected value.
A ring-width index compares an observed growth measurement with an independently established expected value.1
Dividing by the expected value normalizes the observation but does not choose or validate a detrending model. Use this tool to calculate dendrochronology ring width index from the supplied measurements and assumptions.
When to use Geology Dendrochronology Ring Width Index Calculator
Use this tool to calculate dendrochronology ring width index from the supplied measurements and assumptions. Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
How to use Geology Dendrochronology Ring Width Index Calculator and understand its results
- Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
- Enter observedRingWidths, independentlyFittedExpectedWidths, using the field meanings and rules below, then run the tool.
- Read ringWidthIndices. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| observedRingWidths | Observed ring widths | list of number | Required |
| independentlyFittedExpectedWidths | Independently fitted expected widths; caller assertion or measurement requiring independent evidence | list of number | Required |
Enter nonempty aligned nonnegative observed ring widths and positive independently fitted expected widths. Divide each observed width by its expected value and retain order. No chronology matching or detrending fit is performed.
ringWidthIndex_i=observedWidth_i/expectedWidth_i Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| ringWidthIndices | Ring Width Indices; follow the units, sign, ordering and evidence convention stated above | list of number |
{
"input": {
"observedRingWidths": [
1,
4
],
"independentlyFittedExpectedWidths": [
2,
2
]
},
"output": {
"ringWidthIndices": [
0.5,
2
]
}
}Limitations and assumptions
Dividing by the expected value normalizes the observation but does not choose or validate a detrending model. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Geology Dendrochronology Cross Dating Calculator for this related task: Crossdating compares a sample series with candidate windows in a reference chronology.
Use Geology Varve Thickness Calculator when its separate inputs and assumptions fit the question: A varve is an independently identified annual sedimentary layer or layer pair under the adopted counting convention.
References
Similar or alternative tools
- Geology Dendrochronology Cross Dating Calculator
Crossdating compares a sample series with candidate windows in a reference chronology.
- Geology Varve Thickness Calculator
A varve is an independently identified annual sedimentary layer or layer pair under the adopted counting convention.