Making time-independent ICON regrid file using CMAQv5.3.1

Hi all,
I’m using CMAQv5.3.1 to simulate value of my air quality project.

Recently, I got a problem from ICON file.

I had to use time-independent ICON file derived from CONC file. (regrid ICON file at CMAQv5.3.1)

But I couldn’t make time-independent ICON file using CONC file because the CONC file time step is not zero.

I’ve already read ‘README’ file, and that file said if CONC file time step was zero, you could make time-independent ICON file.

But I’m using CONC file that its time step is not zero for my project. So I want to make time-independent ICON file using CONC file with non-zero tstep value.

Is there any solution to release this problem???
Please let me know your opinion for make time-independent ICON file.

Thank you

HyeonYeong Park

You should be able to use the m3tools program m3edhdr to change a time dependent file to a time independent file.

The steps would be something like this:

setenv INFILE /path/to/your/
m3edhdr << EOF
(hit enter twice)

After doing that, TSTEP of your file should be 0 which indicates a time independent file.

That won’t do it, because of other internal integrity-checks in the file; in particular, the TFLAG won’t be correct.

Instead, you need to use M3Tools program m3tshift with an output time-step of 0. See

Thanks @cjcoats for correcting my advice.

Thanks all for your replying!

I tried to use M3Tools, but I couldn’t solve a fundamental problem of that. :joy:

So I modified ic_out.f file!

There was a algorithm that reflect CCTM CONC file’s TSTEP!

So, I modified that part by adding ‘TSTEP=0’

I’m really appreciate to get your advices :slight_smile:

And I hope that my solution help your studies!

Thank you :slight_smile: