Surge Residual Minus Astronomical
Subtract a bracketed interpolated astronomical-tide series from observed levels on the same datum; residual includes all non-tidal errors/processes, not purely meteorological surge.
Description
Observed water level minus astronomical tide leaves a residual.
Observed water level minus astronomical tide leaves a residual. That residual contains all non-tidal processes and measurement errors.
Subtract a bracketed interpolated astronomical-tide series from observed levels on the same datum; residual includes all non-tidal errors/processes, not purely meteorological surge.
When to use Surge Residual Minus Astronomical
Use this tool to subtract a bracketed interpolated astronomical-tide series from observed levels on the same datum; residual includes all non-tidal errors/processes, not purely meteorological surge.
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 Surge Residual Minus Astronomical 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 observationTimesHours, observedWaterLevelsM, tidePredictionTimesHours, predictedTideLevelsM using the field table and calculation rules, then run the tool.
- Read surgeResidualsM, maximumResidualM, minimumResidualM. 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 |
|---|---|---|---|
| observationTimesHours | Observation times hours | list of number | Required |
| observedWaterLevelsM | Observed water levels m | list of number | Required |
| tidePredictionTimesHours | Tide prediction times hours | list of number | Required |
| predictedTideLevelsM | Predicted tide levels m | list of number | Required |
Use increasing observation and prediction hours and aligned level series on one datum. Interpolate predictions only within their time span, subtract, and return all residuals and extrema.1
Paired lists must be nonempty and have equal lengths. Each sequence checked for increasing order must contain at least two strictly increasing values.
residual = observed level − interpolated predicted tide Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| surgeResidualsM | Surge residuals m | list of number |
| maximumResidualM | Maximum residual m | number |
| minimumResidualM | Minimum residual m | number |
{
"input": {
"observationTimesHours": [
0,
1,
2
],
"observedWaterLevelsM": [
1,
3,
2
],
"tidePredictionTimesHours": [
0,
2
],
"predictedTideLevelsM": [
1,
1
]
},
"output": {
"surgeResidualsM": [
0,
2,
1
],
"maximumResidualM": 2,
"minimumResidualM": 0
}
}Limitations and assumptions
No extrapolation; residual is not necessarily purely meteorological surge.
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 Tidal Constituent Amplitude Combiner: Synthesize supplied harmonic tidal constituents with explicit phase/time datum; not a fixed six-hour cosine interpolation or prediction of surge residuals. For a complementary task, use Runup Stockdon Total: Evaluate the empirical Stockdon 2006 general-beach R2 formulation and add supplied still water; not a dune overtopping probability, tsunami model or guaranteed maximum.
References
-
Surge Residual Minus Astronomical — tool.io
Similar or alternative tools
- Tidal Constituent Amplitude Combiner
Synthesize supplied harmonic tidal constituents with explicit phase/time datum; not a fixed six-hour cosine interpolation or prediction of surge residuals.
- Runup Stockdon Total
Evaluate the empirical Stockdon 2006 general-beach R2 formulation and add supplied still water; not a dune overtopping probability, tsunami model or guaranteed maximum.