Firn Density Depth Profile

Evaluate an explicitly calibrated exponential firn density-depth profile; distinct from stage-specific temperature/accumulation densification kinetics.

Description

Firn densifies from surface snow toward compact ice.

Firn densifies from surface snow toward compact ice. An exponential density profile provides a calibrated depth approximation.

Evaluate an explicitly calibrated exponential firn density-depth profile; distinct from stage-specific temperature/accumulation densification kinetics.

When to use Firn Density Depth Profile

Use this for the following task: Evaluate an explicitly calibrated exponential firn density-depth profile; distinct from stage-specific temperature/accumulation densification kinetics.

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 Firn Density Depth Profile 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 depthsM, surfaceDensityKgPerM3, iceDensityKgPerM3, densificationLengthM using the field table, then run the tool.
Read densitiesKgPerM3. 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
depthsM	Depths m	list of number; each entry: number	Required
surfaceDensityKgPerM3	Surface density kg per m3	number	Required
iceDensityKgPerM3	Ice density kg per m3	number	Required
densificationLengthM	Densification length m	number	Required

Require nonempty nonnegative depths, positive density/length parameters and surface density no greater than ice density. Evaluate the profile without fitting parameters.^[1]

ρ(z) = ρice − (ρice−ρsurface)e^(−z/length)

This summarizes the declared operation. Units, indexing, inclusivity and exceptional cases are explained in the surrounding text.

Output field	Meaning	Value type
densitiesKgPerM3	Densities kg per m3	list of number

json

{
  "input": {
    "depthsM": [
      0,
      10,
      20
    ],
    "surfaceDensityKgPerM3": 300,
    "iceDensityKgPerM3": 900,
    "densificationLengthM": 10
  },
  "output": {
    "densitiesKgPerM3": [
      300,
      679.2723352971345,
      818.7988300580324
    ]
  }
}

Limitations and assumptions

This is a depth profile, not temperature/accumulation-dependent stage kinetics.

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 Densification Stage Herron Langway for this operation: Evaluate instantaneous Herron–Langway-form stage kinetics k(T)·accumulation^p·(rho_ice−rho), using supplied stage boundary and unit-compatible prefactors; not an integrated age-depth model. For a complementary task, use Firn Air Content Percentage for this operation: Integrate air volume fraction 1−rho/rho_ice through layered firn; assumes pore space is air and excludes liquid water and pressure-compressed gas.

The implementation reference documents the exact calculation, supported input shapes and returned fields.

References

Firn Density Depth Profile — tool.io

Similar or alternative tools

Densification Stage Herron Langway
Evaluate instantaneous Herron–Langway-form stage kinetics k(T)·accumulation^p·(rho_ice−rho), using supplied stage boundary and unit-compatible prefactors; not an integrated age-depth model.
Firn Air Content Percentage
Integrate air volume fraction 1−rho/rho_ice through layered firn; assumes pore space is air and excludes liquid water and pressure-compressed gas.