shypFun.03110

<p>vector of the 6 van Genuchten-Mualem model parameters, order is sensitve and has to be given as:</p><table><tr><td>
      <code>thr</code></td>
<td>residual water water content [cm cm-3]</td>
<td>
      <code>ths</code></td>
</tr><tr><td>saturated water water content [cm cm-3]</td>
<td>
      <code>alf1</code></td>
<td>inverse of the air entry pressure head [cm]</td>
</tr><tr><td>
      <code>n1</code></td>
<td>width of pore size distribution [ - ]</td>
<td>
      <code>Ks</code></td>
</tr><tr><td>saturated conductivity [cm d-1]</td>
<td>
      <code>tau</code></td>
<td>exponent of <code>Se</code> in the capillary conductivity model, sometimes denoted in the literature as <code>l</code> [ - ]</td>
</tr></table>

<p>pressure heads [cm] for which the corresponding retention and conductivity values are calculated.</p>

<p>Calculates the soil hydraulic property function values based on given pressure heads. The function calculates the base function of Fredlund and Xing Fredlund.1994spsh.</p>

Estimates model parameters of soil hydraulic property functions by inverting measured data. A wide range of hydraulic models, weighting schemes,
global optimization algorithms, Markov chain Monte Carlo samplers, and extended statistical analyses of results are provided.
Prediction of soil hydraulic property model parameters and common soil properties using pedotransfer functions is facilitated.
Parameter estimation is based on identically and independentally distributed (weighted) model residuals, and simple model selection criteria (Hoege, M., Woehling, T., and Nowak, W. (2018) <doi:10.1002/2017WR021902>) can be calculated.
The included models are the van Genuchten-Mualem in its unimodal, bimodal and trimodal form, the the Kosugi 2 parametric-Mualem model, and the Fredlund-Xing model.
All models can be extended to account for non-capillary water storage and conductivity (Weber, T.K.D., Durner, W., Streck, T. and Diamantopoulos, E. (2019) <doi:10.1029/2018WR024584>.
The isothermal vapour conductivity (Saito, H., Simunek, J. and Mohanty, B.P. (2006) <doi:10.2136/vzj2006.0007>) is calculated based on
volumetric air space and a selection of different tortuosity models:
(Grable, A.R., Siemer, E.G. (1968) <doi:10.2136/sssaj1968.03615995003200020011x>, Lai, S.H., Tiedje J.M., Erickson, E. (1976) <doi:10.2136/sssaj1976.03615995004000010006x>,
Moldrup, P., Olesen, T., Rolston, D.E., and Yamaguchi, T. (1997) <doi:10.1097/00010694-199709000-00004>, Moldrup, P., Olesen, T., Yoshikawa, S., Komatsu, T., and Rolston, D.E. (2004) <doi:10.2136/sssaj2004.7500>,
Moldrup, P., Olesen, T., Yoshikawa, S., Komatsu, T., and Rolston, D.E. (2005) <doi:10.1097/01.ss.0000196768.44165.1f>, Millington, R.J., Quirk, J.P. (1961) <doi:10.1039/TF9615701200>,
Penman, H.L. (1940) <doi:10.1017/S0021859600048164>, and Xu, X, Nieber, J.L. Gupta, S.C. (1992) <doi:10.2136/sssaj1992.03615995005600060014x>).

Tobias Weber

`thr`	residual water water content [cm cm-3]	`ths`
saturated water water content [cm cm-3]	`alf1`	inverse of the air entry pressure head [cm]
`n1`	width of pore size distribution [ - ]	`Ks`
saturated conductivity [cm d-1]	`tau`	exponent of `Se` in the capillary conductivity model, sometimes denoted in the literature as `l` [ - ]

shypFun.03110: Unimodal Fredlund-Xing - Mualem Model

Description

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Examples