Gate Velocity Balance Flux
Invert integrated upstream water-equivalent net balance to steady depth-mean gate velocity; negative balance demands inward flux under this ideal storage-free budget.
Description
A steady glacier budget requires gate discharge to balance integrated upstream net accumulation.
A steady glacier budget requires gate discharge to balance integrated upstream net accumulation. Water-equivalent balance must be converted into ice volume.1
Invert integrated upstream water-equivalent net balance to steady depth-mean gate velocity; negative balance demands inward flux under this ideal storage-free budget.
When to use Gate Velocity Balance Flux
Use this for the following task: Invert integrated upstream water-equivalent net balance to steady depth-mean gate velocity; negative balance demands inward flux under this ideal storage-free budget.
Prepare the measurements and calibration parameters in the declared units. Keep vector entries aligned and choose a consistent spatial frame and time basis.
How to use Gate Velocity Balance Flux and understand its results
- Prepare the measurements and calibration parameters in the declared units. Keep vector entries aligned and choose a consistent spatial frame and time basis.
- Enter upstreamAreasM2, upstreamBalancesMwePerYear, gateCrossSectionM2, waterDensityKgPerM3, iceDensityKgPerM3 using the field table, then run the tool.
- Read requiredIceFluxM3PerYear, balanceDepthMeanGateVelocityMPerYear. Interpret flags, units, ordering and placeholder values using the rules below.
- Review any reported issue or failed check, correct the supplied values when appropriate, and verify the result in its intended context.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| upstreamAreasM2 | Upstream areas m2 | list of number; each entry: number | Required |
| upstreamBalancesMwePerYear | Upstream balances mwe per year | list of number; each entry: number | Required |
| gateCrossSectionM2 | Gate cross section m2 | number | Required |
| waterDensityKgPerM3 | Water density kg per m3 | number | Required |
| iceDensityKgPerM3 | Ice density kg per m3 | number | Required |
Pair positive upstream areas with signed balances, and require positive gate area and densities. Integrate the balances and infer signed depth-mean gate velocity.2
Qice = Σ(area × balance) ρwater/ρice; umean = Qice/gateArea This summarizes the declared operation. Units, indexing, inclusivity and exceptional cases are explained in the surrounding text.
| Output field | Meaning | Value type |
|---|---|---|
| requiredIceFluxM3PerYear | Required ice flux m3 per year | number |
| balanceDepthMeanGateVelocityMPerYear | Balance depth mean gate velocity m per year | number |
{
"input": {
"upstreamAreasM2": [
100,
200
],
"upstreamBalancesMwePerYear": [
1,
0.5
],
"gateCrossSectionM2": 10,
"waterDensityKgPerM3": 1000,
"iceDensityKgPerM3": 900
},
"output": {
"requiredIceFluxM3PerYear": 222.22222222222223,
"balanceDepthMeanGateVelocityMPerYear": 22.22222222222222
}
}Limitations and assumptions
The budget has no storage change. Negative balance implies required inward flux in this model; measured surface velocity is not directly comparable without calibration.
Constants and empirical coefficients are supplied rather than calibrated. Check units and observational applicability before interpreting the model. Malformed requests produce input errors. A successfully evaluated request can still contain false flags, empty result lists or a result outside the supplied threshold; those outcomes have the meanings stated above.
Alternative or Complementary methods
Choose Flux Gate Discharge for this operation: Integrate signed normal ice flux over supplied gate strips with depth-mean/surface velocity calibration; widths are physical section measurements, not geodesy coordinates. For a complementary task, use Residual Flux Mass Balance Checker for this operation: Audit a bounded glacier mass-control-volume budget against independent observed storage change; residual sign is observed minus predicted and missing processes are not diagnosed.
Further background: Glacier accumulation, ablation and mass balance.
References
Similar or alternative tools
- Flux Gate Discharge
Integrate signed normal ice flux over supplied gate strips with depth-mean/surface velocity calibration; widths are physical section measurements, not geodesy coordinates.
- Residual Flux Mass Balance Checker
Audit a bounded glacier mass-control-volume budget against independent observed storage change; residual sign is observed minus predicted and missing processes are not diagnosed.