CLM4 Irrigation Bug

[xujunhan@gmail_com]

Dear all,

I want to use the real irrigation data in the CLM4.

I think there is a bug in the irrigation procedure of CLM4.

In Hydrology1Mod, the following lines:

if (n_irrig_steps_left(c) > 0) then
qflx_irrig(c) = irrig_rate(c)
n_irrig_steps_left(c) = n_irrig_steps_left(c) - 1
else
qflx_irrig(c) = 0._r8
end if

For example, if I have two pfts in one column, the n_irrig_steps_left of the same column will be decreased twice. So there are only 2 steps irrigation, not 4 steps irrigation in the document.

I used "print*,n_irrig_steps_left(c),irrig_rate(c)" before these lines. You can see the decrease of n_irrig_steps_left:

4 4.54567896667867899E-004
3 4.54567896667867899E-004
4 4.54567896667867899E-004
3 4.54567896667867899E-004
4 4.54567896667867899E-004
3 4.54567896667867899E-004
4 4.54567896667867899E-004
3 4.54567896667867899E-004
2 4.54567896667867899E-004
1 4.54567896667867899E-004
2 4.54567896667867899E-004
1 4.54567896667867899E-004
2 4.54567896667867899E-004
1 4.54567896667867899E-004
2 4.54567896667867899E-004
1 4.54567896667867899E-004

There should be lines such as:

3 4.54567896667867899E-004
2 4.54567896667867899E-004
3 4.54567896667867899E-004
2 4.54567896667867899E-004

Best Regards!

Xujun

 

[slevis]

Xujun,

Thank you for pointing this out. We will post an update after looking into this.

Sam

 

[slevis]

Xujun,

I agree that your model output suggests an error somewhere.

We have not seen this behavior in the CLM4 because we set create_crop_landunit=.true. when we run with irrigation. This way we have only one crop per column. However, if you were not setting create_crop_landunit=.true. you should be getting an error message about it. So something else may be going on...

Have you possibly changed the list of pfts in the pft-physiology file? Coincidentally, I did that a few days ago in the process of merging the crop model to the irrigation model. Then I forgot to change a relevant constant in clm_varpar.F90 (numcft), so I encountered the same problem that you describe!

If you think that your problem has a different cause, please provide more detail about what you're doing.

Sam

 

[xujunhan@gmail_com]

Dear Sam,

I want to study the irrigation scheduling with CLM4.

I assign 70% of pft type 5 and 30% bare ground for each grid cell.

Then the irrigation rate and the irrigation steps in the initial file were changed during some steps to tell CLM4 to do irrigation.

I agree with you, if we only use the irrigated crop type, there will not be this problem.

But if we use this irrigated crop type, CLM4 will calculate the irrigation requirement automatically. But I want to calculate the irrigation requirement by myself.

Best Regards!

Xujun