Permafrost Active Layer Stefan Solution Calculator
Ideal soil Stefan sharp-front thaw depth using independently verified volumetric latent heat and SURFACE thaw index; no snow/groundn-factor inferred, not lake ice growth or real active-layer forecast. Caller independently establishes homogeneous observation coverage and model/reference applicability; not observed future climate, crop suitability or validated drought severity.
Description
The ideal Stefan thaw-depth model balances conductive heat with latent heat.
The ideal Stefan thaw-depth model balances conductive heat with latent heat.1
Its square-root estimate depends on independently applicable soil and surface-thawing inputs. Use Permafrost Active Layer Stefan Solution Calculator to evaluate the supplied inputs under the model explained below.
When to use Permafrost Active Layer Stefan Solution Calculator
Use Permafrost Active Layer Stefan Solution Calculator to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.
How to use Permafrost Active Layer Stefan Solution Calculator and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter Soil conductivity w per meter k, Caller surface thawing degree days, Caller volumetric latent heat j per m3 using the field table and validation rules below, then run the tool.
- Read Stefan ideal thaw depth meters; interpret the units, signs, ordering and unknown-value placeholders described below.
- Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| soilConductivityWPerMeterK | Soil conductivity w per meter k | number | Required; constraints below |
| callerSurfaceThawingDegreeDays | Caller surface thawing degree days | number | Required; constraints below |
| callerVolumetricLatentHeatJPerM3 | Caller volumetric latent heat j per m3 | number | Required; constraints below |
Enter positive soil conductivity in W/(m·K), nonnegative surface thawing degree-days and positive volumetric latent heat in J/m³. Convert degree-days to degree-seconds using 86400 and return sqrt(2×conductivity×degreeDays×86400/latentHeat) in m. Zero degree-days return zero depth. Soil layering, sensible heat and surface-to-ground transfer must be addressed independently.
thawDepthM=sqrt(2×conductivity×surfaceDegreeDays×86400/volumetricLatentHeat) Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| stefanIdealThawDepthMeters | Stefan ideal thaw depth meters | number |
{
"input": {
"soilConductivityWPerMeterK": 1,
"callerSurfaceThawingDegreeDays": 1,
"callerVolumetricLatentHeatJPerM3": 172800
},
"output": {
"stefanIdealThawDepthMeters": 1
}
}Limitations and assumptions
Its square-root estimate depends on independently applicable soil and surface-thawing inputs. Apply the exact scope and assumptions explained above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.
Alternative or Complementary methods
Use Concrete Freeze Thaw Cycles Calculator for a related task: Freeze-thaw counting requires distinct freezing and thawing thresholds and a chosen cycle convention.
Use Design Freezing Index Selection Lookup for a related task: A design freezing index depends on a documented site, method and reference period.
References
Similar or alternative tools
- Concrete Freeze Thaw Cycles Calculator
Freeze-thaw counting requires distinct freezing and thawing thresholds and a chosen cycle convention.
- Design Freezing Index Selection Lookup
A design freezing index depends on a documented site, method and reference period.