SSGampt {HydroMe} | R Documentation |
This selfstarting function estimates ks and (A) during infiltration. It has an initial attribute that creates initial estimates of the parameters ks and A
SSGampt(input, ks, A)
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 |
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
It may be necessary to transform the instantaneous infiltration rates to avoid the function returning negative ks values
Omuto, Christian Thine
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
SShort, SSphilip
##---- 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