Cup Anemometer Calibration Constant
Calibrate measured cup rotation rates to reference wind with explicit intercept/slope and extrapolation flag; not a universal instrument constant, gust response or certified sensor accuracy.
Description
A cup anemometer requires calibration between rotation rate and reference wind speed.
A cup anemometer requires calibration between rotation rate and reference wind speed. A fitted intercept allows the measurement relation to differ from a simple proportional constant.1
Calibrate measured cup rotation rates to reference wind with explicit intercept/slope and extrapolation flag; not a universal instrument constant, gust response or certified sensor accuracy.
When to use Cup Anemometer Calibration Constant
Use this tool to calibrate measured cup rotation rates to reference wind with explicit intercept/slope and extrapolation flag; not a universal instrument constant, gust response or certified sensor accuracy.
Prepare the observed sounding, cloud records or forecast verification data. Check pressure and height coordinates, wind conventions and the stated units.
How to use Cup Anemometer Calibration Constant and understand its results
- Prepare the observed sounding, cloud records or forecast verification data. Check pressure and height coordinates, wind conventions and the stated units.
- Enter observedCupRotationsPerSecond, referenceWindSpeedsMPerSecond, predictionRotationsPerSecond using the field table and calculation rules, then run the tool.
- Read calibratedSpeedPerRotation, calibratedWindOffsetMPerSecond, predictedWindSpeedMPerSecond, predictionOutsideCalibrationRange. 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 |
|---|---|---|---|
| observedCupRotationsPerSecond | Observed cup rotations per second | list of number | Required |
| referenceWindSpeedsMPerSecond | Reference wind speeds m per second | list of number | Required |
| predictionRotationsPerSecond | Prediction rotations per second | number | Required |
Pair nonnegative rotation rates and reference speeds with at least two observations and varying rates. Fit ordinary least squares, require positive slope, and evaluate a nonnegative prediction. Flag rates strictly outside the calibration range; endpoints are inside.
The least-squares fit needs at least two aligned observations and a varying independent variable; a constant dependent variable has reported R² of 1.
predicted wind = fitted offset + fitted slope × rotations per second Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| calibratedSpeedPerRotation | Calibrated speed per rotation | number |
| calibratedWindOffsetMPerSecond | Calibrated wind offset m per second | number |
| predictedWindSpeedMPerSecond | Predicted wind speed m per second | number |
| predictionOutsideCalibrationRange | Prediction outside calibration range | boolean |
{
"input": {
"observedCupRotationsPerSecond": [
1,
2,
3
],
"referenceWindSpeedsMPerSecond": [
3,
5,
7
],
"predictionRotationsPerSecond": 4
},
"output": {
"calibratedSpeedPerRotation": 2,
"calibratedWindOffsetMPerSecond": 1,
"predictedWindSpeedMPerSecond": 9,
"predictionOutsideCalibrationRange": true
}
}Limitations and assumptions
An out-of-range flag does not stop extrapolation. Dynamic gust response and certified sensor accuracy are not established.
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. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Ensemble Spread Error Consistency Checker: Compare case-wise ensemble-mean RMSE with unbiased member variance under finite-M exchangeability factor sqrt(1+1/M); descriptive comparison, no reliability test/independence claim and perfect zero-error ratio undefined. For a complementary task, use Ageostrophic Component Magnitude: Difference measured and independently supplied geostrophic wind vectors, not scalar speed subtraction or computed pressure-gradient wind.
References
-
Cup Anemometer Calibration Constant — tool.io
Similar or alternative tools
- Ensemble Spread Error Consistency Checker
Compare case-wise ensemble-mean RMSE with unbiased member variance under finite-M exchangeability factor sqrt(1+1/M); descriptive comparison, no reliability test/independence claim and perfect zero-error ratio undefined.
- Ageostrophic Component Magnitude
Difference measured and independently supplied geostrophic wind vectors, not scalar speed subtraction or computed pressure-gradient wind.