SSGampt {HydroMe}R Documentation

A selfstarting function for estimating infiltration parameters in the Green-Ampt model

Description

This selfstarting function estimates ks and (A) during infiltration. It has an initial attribute that creates initial estimates of the parameters ks and A

Usage

SSGampt(input, ks, A)

Arguments

input a numeric vector of values at which to evaluate the model. It should contain the cummulative infiltration capacities
ks a numeric parameter representing the asymptote to the cummulative-infiltration axis (when input values are very large)
A a numeric parameter representing the integral measure of the potential of wetting front in increasing soil moisture during infiltration

Value

a numeric vector of the same length as input. It is the value of the expression ks+(A/input) . It represents the fitted estimates of infiltration rates

Note

It may be necessary to transform the instantaneous infiltration rates to avoid the function returning negative ks values

Author(s)

Omuto, Christian Thine

References

Green, W.A., Ampt, G.A., 1911 Studies on soil physics: 1. the flow of air and water through soils Journal of Agricultural Science 4, 1-24

See Also

SShort, SSphilip

Examples

##---- Use infiltration data---- 
data(infiltration) 
Gampt.nls <-nls(log(Rate)~SSGampt(Cumrate, ks, A), data=infiltration) 
summary(Gampt.nls)# Call summary to desplay the results 


[Package HydroMe version 1.0 Index]