Numerical errors in HYDRUS

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litlux
Posts: 2
Joined: Thu Jul 04, 2019 4:24 am
Location: Korea

Numerical errors in HYDRUS

Post by litlux » Thu Jul 04, 2019 7:04 am

Hi.

I am sorry for taking your time. My question seems stupid but.
I am running an inverse model of unsaturated soil column with height of 45cm with the rainfall rate of 5.1cm/hr I input the values of moisture content at 3 observation points running time from 0.065h to 164 hour.

Every time I change the initial estimate, the results for fitted values were changed as well. Should it be the same?

Thank you so much for your help.

Jirka
Posts: 4712
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Numerical errors in HYDRUS

Post by Jirka » Wed Jul 10, 2019 1:33 pm

This would indicate that the parameters are not identifiable. See the following article on the issue:

Šimůnek, J., and J. W. Hopmans, Parameter Optimization and Nonlinear Fitting, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 1.7, Eds. J. H. Dane and G. C. Topp, Third edition, SSSA, Madison, WI, 139-157, 2002.

J.

litlux
Posts: 2
Joined: Thu Jul 04, 2019 4:24 am
Location: Korea

Re: Numerical errors in HYDRUS

Post by litlux » Mon Jul 15, 2019 12:48 am

Jirka wrote:
Wed Jul 10, 2019 1:33 pm
This would indicate that the parameters are not identifiable. See the following article on the issue:

Šimůnek, J., and J. W. Hopmans, Parameter Optimization and Nonlinear Fitting, In: Methods of Soil Analysis, Part 4, Physical Methods, Chapter 1.7, Eds. J. H. Dane and G. C. Topp, Third edition, SSSA, Madison, WI, 139-157, 2002.

J.
Dear J., Thank you so much for your help

Best regards

Tho Tran

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