Scap {SoilHyP}

Rescaled capillary saturation function

Description

Rescaled capillary saturation function by Iden and Durner (2014)

Usage

Scap(suc, par.shp, modality = c("uni"), suc.negativ = FALSE)

Arguments

suc

Suction/pressure heads. Negative if suc.negativ = TRUE

par.shp

named parameter in list or vector

modality

pore size distribution ('uni' or 'bi')

suc.negativ

set TRUE if suction/pressure heads are negative and FALSE if positive

Details

par.shp:

alfa [1/L]: van Genuchten shape parameter
n [-]: van Genuchten shape parameter
m [-]: shape parameter (m = 1-(1/n) if missing)
h0 [L]: suction at water content of 0 (i.e. oven dryness) (h0 = 10^6.8 if missing, corresponding to oven dryness at 105°C (Schneider and Goss, 2012))

par.shp (additional for bimodal (modality = 'bi') pore size distribution:)

w2 [-]: weigthing between pore space distribution
alfa2 [1/L]: van Genuchten parameter alfa for second pore space distribution
n2 [-]: van Genuchten parameter n for second pore space distribution
m2 [-]: shape parameter (m = 1-(1/n2) if missing)

Scap(h) = (Gamma(h)- Gamma(h0))/(1 - Gamma(h0))
Gamma descripes the capillary saturation function. Here the saturation function of van Genuchten is used:
gamma(h) = (1/(1 + -suc * alfa)^n)^m (see also Sat)

References

Iden, S., Durner, W. (2014). Comment to Simple consistent models for water retention and hydraulic conductivity in the complete moisture range by A. Peters. Water Resour. Res. 50, 7530–7534.

Schneider, M., & Goss, K. U. (2012). Prediction of the water sorption isotherm in air dry soils. Geoderma, 170, 64-69.