To improve the precision of parameters? estimation in Philip infiltration
model, chaos gray-coded genetic algorithm was introduced. The optimization
algorithm made it possible to change from the discrete form of time
perturbation function to a more flexible continuous form. The software RETC
and Hydrus-1D were applied to estimate the soil physical parameters and
referenced cumulative infiltration for seven different soils in the USDA soil
texture triangle. The comparisons among Philip infiltration model with
different numerical calculation methods showed that using optimization
technique can increase the Nash and Sutcliffe efficiency from 0.82 to 0.97,
and decrease the percent bias from 14% to 2%. The results indicated that
using the discrete relationship of time perturbation function in Philip
infiltration model?s numerical calculation underestimated model?s parameters,
but this problem can be corrected a lot by using optimization algorithm. We
acknowledge that in this study the fitting of time perturbation function,
Chebyshev polynomial with order 20, did not perform perfectly near saturated
and residue water content. So exploring a more appropriate function for
representing time perturbation function is valuable in the future.
An application of chaos gray-encoded genetic algorithm for Philip infiltration model
