Southern Oscillation Index Normalized
Compute an explicitly ordered two-station standardized pressure-difference index with caller baseline normalization/scale; no mutable station climatology or official SOI method inferred.
Description
A standardized pressure-difference index depends on station order and baseline statistics.
A standardized pressure-difference index depends on station order and baseline statistics. Those choices determine its sign and scale.
Compute an explicitly ordered two-station standardized pressure-difference index with caller baseline normalization/scale; no mutable station climatology or official SOI method inferred.
When to use Southern Oscillation Index Normalized
Use this tool to compute an explicitly ordered two-station standardized pressure-difference index with caller baseline normalization/scale; no mutable station climatology or official SOI method inferred.
Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.
How to use Southern Oscillation Index Normalized and understand its results
- Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.
- Enter stationPressuresHpa, stationBaselineMeansHpa, stationBaselineStandardDeviationsHpa, baselineStandardizedDifferenceMean, baselineStandardizedDifferenceSd, indexScale using the field table and calculation rules, then run the tool.
- Read standardizedStationAnomalies, southernOscillationIndex. 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 |
|---|---|---|---|
| stationPressuresHpa | Station pressures hPa | list of number | Required |
| stationBaselineMeansHpa | Station baseline means hPa | list of number | Required |
| stationBaselineStandardDeviationsHpa | Station baseline standard deviations hPa | list of number | Required |
| baselineStandardizedDifferenceMean | Baseline standardized difference mean | number | Required |
| baselineStandardizedDifferenceSd | Baseline standardized difference sd | number | Required |
| indexScale | Index scale | number | Required |
Supply exactly two pressures, means and positive station SDs, plus positive difference SD and scale. Return standardized anomalies and the signed index.1
index = scale × (standardized station 0 − station 1 − baseline difference mean)/difference SD Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| standardizedStationAnomalies | Standardized station anomalies | list of number |
| southernOscillationIndex | Southern oscillation index | number |
{
"input": {
"stationPressuresHpa": [
1000,
1005
],
"stationBaselineMeansHpa": [
995,
1000
],
"stationBaselineStandardDeviationsHpa": [
5,
5
],
"baselineStandardizedDifferenceMean": 0,
"baselineStandardizedDifferenceSd": 2,
"indexScale": 10
},
"output": {
"standardizedStationAnomalies": [
1,
1
],
"southernOscillationIndex": 0
}
}Limitations and assumptions
No station climatology or official SOI methodology is inferred.
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.
Alternative or Complementary methods
Use Nino34 Anomaly Classifier: Screen supplied monthly Nino3.4 anomalies using a caller running-window/consecutive-phase policy; inputs must be contiguous months on one baseline and outputs are not an official ENSO designation. For a complementary task, use Ocean PH Drop Decade Rate: Fit observed pH trend and its multiplicative hydrogen-activity interpretation on one consistent pH scale; pH is logarithmic, and activity is not molar concentration without an activity convention.
References
-
Southern Oscillation Index Normalized — tool.io
Similar or alternative tools
- Nino34 Anomaly Classifier
Screen supplied monthly Nino3.4 anomalies using a caller running-window/consecutive-phase policy; inputs must be contiguous months on one baseline and outputs are not an official ENSO designation.
- Ocean PH Drop Decade Rate
Fit observed pH trend and its multiplicative hydrogen-activity interpretation on one consistent pH scale; pH is logarithmic, and activity is not molar concentration without an activity convention.