Issue with the inverse model run in Hydrus 1D

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Hydraus_1d_RD
Posts: 16
Joined: Thu Dec 17, 2020 10:11 pm
Location: USA

Issue with the inverse model run in Hydrus 1D

Post by Hydraus_1d_RD » Tue Jan 19, 2021 9:21 pm

Dear all,
I’m presently trying to run an inverse model that is stopping even on the very first few iterations. Some details about my models are:
It has three material types and three layers/subregions and it runs for 6 years on daily time steps. I’m interested in the last three years of the model run outputs.
For the 1st subregions, I have observed soil moisture content time series data. Now I’m trying to estimate soil hydraulic properties for the top two layers by calibrating the averaged (model computed) soil moisture contents with their observed values. In the “Data for inverse solution” table, my entries are like this:
X theta Type Position Weight
1138 0.112562 2 1 1
… in total 999 entries.
I updated the sector.in file to have 999 print time values.
This is what my DOS screen shows:
3 0.1059D+02 0.1544E+00 0.3853E+00 0.2016E-01 0.1145E+01 0.4339E+02 0.1229E+00 0.1409E+00 0.6108E-02 0.1061E+01 0.9676E+00
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
The numerical solution has not converged !
Numerical solution has been stopped since it has not converged in 10 consecutiv
e time steps !


Press Enter to continue




Would you please let me know if you have any suggestions regarding either my inverse model set up or convergence issue?
Thank you!
Sincerely,
A Hydrus-1D user

Jirka
Posts: 5216
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Issue with the inverse model run in Hydrus 1D

Post by Jirka » Tue Jan 19, 2021 9:48 pm

It seems that you are posting almost half of all questions in the HYDRUS-1D discussion forum. You should perhaps try to do some of our tutorials and become more familiar with the software before proceeding with your own projects. J.

Hydraus_1d_RD
Posts: 16
Joined: Thu Dec 17, 2020 10:11 pm
Location: USA

Re: Issue with the inverse model run in Hydrus 1D

Post by Hydraus_1d_RD » Fri Jan 22, 2021 6:26 am

Thank you for your suggestion, Jirka. After reviewing some of the pre-installed inverse solution examples for 1D case and the Chapter 9 in Hydrus 1D v 4.17 (especially pages 137 and 138), I'm still not sure how to specify sublayer-based averaged moisture content (defined as: volume of water in a layer / layer length, e.g., volume in layer 2/length of layer 2) as a calibration target. The Table 9.1 in the latest version of the manual is a bit confusing (to me), as it uses iObs, -Obs, and -iLay. Furthermore, in one of the solved examples I noted that while the Table 1 with Type 2 and location 0 says volume of water in the soil profile, the calibration is made to the averaged moisture content of the whole profile and not to the volume of water in the profile. Therefore, I'd really appreciate your guidance and some clarification. I also would like to acknowledge that I sometimes have posted a number of questions, but I also believe that my questions can be helpful to the other users, as they might face similar issues as I do (at present).
Sincerely,
A Hydrus-1D user

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