computeTSA {sarp.snowprofile}

Compute Threshold Sum Approach (TSA, lemons, yellow flags, 'Nieten')

Description

This routine computes the traditional lemons (German 'Nieten') based on absolute thresholds. Since the thresholds are defined in Monti (2014) with different thresholds for manual versus observed profiles, this routine switches between the appropriate thresholds based on the ⁠$type⁠ field of the input profile. While manual and whiteboard profiles get one set of thresholds, modeled, vstation, and aggregate type profiles get another set.

Usage

computeTSA(x, target = c("interface", "layer"))

## S3 method for class 'snowprofileSet'
computeTSA(x, target = c("interface", "layer"))

## S3 method for class 'snowprofile'
computeTSA(x, target = c("interface", "layer"))

Arguments

x

a snowprofile or snowprofileSet

target

Do you want to compute the index for the layers or for the layer interfaces? defaults to both.

Value

New layer properties tsa/tsa_interface describing the threshold sums are added to the profile layers. The TSA sums up to 6 indicators, whereas >= 5 indicators indicate structurally unstable layers/interfaces.

Methods (by class)

• computeTSA(snowprofileSet): for snowprofileSets

• computeTSA(snowprofile): for snowprofiles

Author(s)

fherla

References

Schweizer, J., & Jamieson, J. B. (2007). A threshold sum approach to stability evaluation of manual snow profiles. Cold Regions Science and Technology, 47(1–2), 50–59. https://doi.org/10.1016/j.coldregions.2006.08.011

Monti, F., Schweizer, J., & Fierz, C. (2014). Hardness estimation and weak layer detection in simulated snow stratigraphy. Cold Regions Science and Technology, 103, 82–90. https://doi.org/10.1016/j.coldregions.2014.03.009

See Also

computeRTA

Examples

## apply function to snowprofileSet
profileset <- computeTSA(SPgroup)

## apply function to snowprofile and plot output
sp <- computeTSA(SPpairs$B_modeled1)
plot(sp, TempProfile = FALSE, main = "TSA")
lines(sp$layers$tsa/6*5,
      sp$layers$height - 0.5*sp$layers$thickness, type = "b", xlim = c(0, 5))
lines(sp$layers$tsa_interface/6*5, sp$layers$height, type = "b", xlim = c(0, 5), col = "red")
abline(h = sp$layers$height, lty = "dotted", col = "grey")
abline(v = 5/6*5, lty = "dashed")