Ice Core Layer Thinning Depth

Propagate layer thickness through supplied vertical-strain residence intervals; negative strain thins and positive strain thickens, without inferring strain from depth.

Description

Vertical strain changes the thickness of an annual ice layer as it travels through the ice column.

Vertical strain changes the thickness of an annual ice layer as it travels through the ice column. Negative strain thins a layer; positive strain thickens it.^[1]

Propagate layer thickness through supplied vertical-strain residence intervals; negative strain thins and positive strain thickens, without inferring strain from depth.

When to use Ice Core Layer Thinning Depth

Use this for the following task: Propagate layer thickness through supplied vertical-strain residence intervals; negative strain thins and positive strain thickens, without inferring strain from depth.

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 Ice Core Layer Thinning Depth 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 initialAnnualLayerThicknessM, residenceDurationsYears, verticalStrainRatesPerYear using the field table, then run the tool.
Read cumulativeLogThinning, thinnedAnnualLayerThicknessM. 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
initialAnnualLayerThicknessM	Initial annual layer thickness m	number	Required
residenceDurationsYears	Residence durations years	list of number; each entry: number	Required
verticalStrainRatesPerYear	Vertical strain rates per year	list of number; each entry: number	Required

Pair nonnegative residence durations with signed strain rates and multiply the positive initial layer thickness by the exponential cumulative factor.^[2]

log factor = Σ ε̇vertical Δyears; thickness = initialThickness exp(log factor)

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

Output field	Meaning	Value type
cumulativeLogThinning	Cumulative log thinning	number
thinnedAnnualLayerThicknessM	Thinned annual layer thickness m	number

json

{
  "input": {
    "initialAnnualLayerThicknessM": 1,
    "residenceDurationsYears": [
      10,
      20
    ],
    "verticalStrainRatesPerYear": [
      -0.01,
      -0.02
    ]
  },
  "output": {
    "cumulativeLogThinning": -0.5,
    "thinnedAnnualLayerThicknessM": 0.6065306597126334
  }
}

Limitations and assumptions

Depth does not determine strain in this tool. The strain history must be supplied independently.

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 Annual Layer Count Age At Depth for this operation: Accumulate interpreted annual-layer counts and separately supplied hiatus years at depth boundaries; ambiguous/missing annuality must be resolved externally. For a complementary task, use Core Bottom Age Extrapolation for this operation: Integrate reciprocal exponentially thinning annual-layer thickness below a reference depth; explicitly a model extrapolation, not observed core chronology or an uncertainty bound.

Further background: Ice rheology.

References

Ice rheology — PISM
Ice Core Layer Thinning Depth — tool.io

Similar or alternative tools

Annual Layer Count Age At Depth
Accumulate interpreted annual-layer counts and separately supplied hiatus years at depth boundaries; ambiguous/missing annuality must be resolved externally.
Core Bottom Age Extrapolation
Integrate reciprocal exponentially thinning annual-layer thickness below a reference depth; explicitly a model extrapolation, not observed core chronology or an uncertainty bound.