SShort {HydroMe}R Documentation

A selfstarting function for estimating the parameters of the Hortons infiltration model

Description

This selfstarting function estimates the infiltration parameters contained in the Hortons model. It has an initial attribute that creates initial estimates of the parameters fc, f0, and k

Usage

SShort(input, fc, f0, lrk)

Arguments

input A numeric vector of Time
fc A numeric parameter representing the final steady infiltration capacity
f0 A numeric parameter representing the initial infiltration capacity
lrk A numeric parameter representing the logarithm of the decay constant

Value

a numeric vector of the same length as input. It is the value of the expression fc+(f0-fc)*exp(-input*lrk) . It represents the fitted estimates of infiltration capacities using the Hortons model

Note

It may be necessary to transform the infiltration capacities to avoid negative values for the asymptotic final steady infiltration capacity

Author(s)

Omuto, Christian Thine

References

Horton , R.E., 1940 An approach towards a physical interpretation of infiltration capacity Soil Science Society of America Proceedings 5, 227-237

See Also

SSphilip, SSGampt

Examples

##-- Use infiltration data 
data(infiltration) 
hort.nls <-nls(Rate~SShort(Time, fc, f0, lrk), data=infiltration) 
plot(hort.nls) # to view the assumption of constant variance of the residuals

[Package HydroMe version 1.0 Index]