Initial Condition With Scaling Factors

A discussion forum for Hydrus-1D users.
Post Reply
RonRainmaple
Posts: 3
Joined: Thu Aug 13, 2015 6:11 pm
Location: USA

Initial Condition With Scaling Factors

Post by RonRainmaple » Thu Aug 13, 2015 10:45 pm

Dear Jirka,

I was trying to set up a hydrus simulation on a specific event. I have the measured water content data from a lysimeter, which will be the initial condition inputs in Soil Profile Summary. Different layers are scaled using the "Axz, Bxz, Dxz" factors. However, from the results I found that for T0, the initial water content is not the same with the ones that I put in. It is scaled. As I understand, the initial condition (water content )should not change. Because if it is the real time zero, it should not be taken into calculation, which means it keeps the input initial condition data as the printed T0. So, in one word, does hydrus scale the initial condition when simulating?
Thanks.

Best,
Ron

Jirka
Posts: 4980
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Initial Condition With Scaling Factors

Post by Jirka » Fri Aug 14, 2015 5:05 am

Although I have not tested it since I’m on vacations, I do not think it does. The specified initial water content should remain the same (even when you specify different scaling factors in different nodes). Obviously, the other variables, such as the initial pressure head and the initial hydraulic conductivity have to change, since the hydraulic properties in each node need to reflect the specified scaling factors.

Similarly, if you specify the initial pressure head, then this variable should remain the same, while the others have to change.

J.

RonRainmaple
Posts: 3
Joined: Thu Aug 13, 2015 6:11 pm
Location: USA

Re: Initial Condition With Scaling Factors

Post by RonRainmaple » Thu Aug 27, 2015 5:40 pm

Hi Jirka,

I tried several times but the initial water content in hydrus still not matching the initial water content that I put in. Here I attached a pic showing that the hydrus initial condition curve always have a strange spike. For the pic, the upper one is the initial water content that I put in. The lower one is the simulated result with the black curve as initial water content. Do you ever find the same happened?

Thanks.

Ron
Attachments
initial comparison.png
initial comparison.png (13.84 KiB) Viewed 3950 times

July
Posts: 6
Joined: Wed Sep 02, 2015 9:59 am
Location: Germany

Number of Print Times

Post by July » Wed Sep 02, 2015 10:19 am

Dear Jirka,

I want to simulate the water flux in a groundwater distant soil with Hydrus 1D. I set the simulation time to exactly one year and so the number of fields in time variable boundary conditions and meteorological conditions. But I cannot increase the number of print times to 365 days. The program requires a number up to 250 and afterwards Hydrus 1D closes. Is 250 days the upper boundary of detailed information? And is there a major difference if I start the initial day with 0 compared to 1? Thank you in advance.

Have a nice day. Best regards,

Julian

Jirka
Posts: 4980
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Initial Condition With Scaling Factors

Post by Jirka » Wed Sep 02, 2015 1:36 pm

It is always mystery to me why people would want more than about 15 print times. Note that print times are in no way related to boundary conditions.

You can start from any time value, including from negative times.

J.

Post Reply