Calibrating Only First Stress Period in PyEMU—How to Set Up add_observations()

[Omowumieru]

Hi,
I'm new to PyEMU and trying to set up a calibration for a MODFLOW model with two stress periods. I want to calibrate the model against observed heads from the first stress period.

In the pf.add_observations() function:

1. Does the filename argument refer to the simulated heads file from flopy run, or should it point to the observed heads file?
2. If it's the simulated heads file, how does PyEMU compare the simulated values to the observed heads to calculate the objective function (phi)?
3. Is there a standard way to make sure only the first stress period is considered during calibration?

I feel like I should probably know this, but I would really appreciate any help or pointers. Thanks in advance!

[jtwhite79]

You can still add all the simulated outputs from the mf6 observation csv file for all stress periods and then only set non-zero weights in the pest control file for the first stress period - only observations with non-zero weight have an influence during parameter adjustment. But its up to you to set the actual observation value in the pest control file for those non-zero weighted quantities.

[Omowumieru]

Thank you! I was able to do this.