Help with WRF OBS-Nudging Process

[Naser]

Dear all,

Hello,

I am trying to run WRF OBS-Nudging and have followed the steps below:

1. I downloaded OBSGRID.exe from the following website:
   WRF Download
2. After compiling the code, I added my little-r files (OBS:YYYY-MM-DD_HH) to the OBSGRID directory. I also linked my met_em files to this directory.
3. I ran OBSGRID.exe. After the run, I obtained the following output files:
   • metoa_em.d01*
   • wrfsfdda_d01
   • OBS_DOMAIN1*
   • qc_obs_raw.d01.YYYY-MM-DD_HH:mm:ss.tttt
   • qc_obs_used.d01.YYYY-MM-DD_HH:mm:ss.tttt
   • plotobs_out.d01.YYYY-MM-DD_HH:mm:ss.tttt
4. I renamed metoa_em.d01* to met_em.d01* and moved them to my WRF directory. I then ran the WRF model with the attached namelist.input.

The model ran without any errors. However, I do not see any significant differences in temperature between the simulation applying OBS-Nudging and a normal run without it.

I suspect there might be an issue with either my steps or the preparation of the little-r files.

• If my method is correct, I may not have properly formatted the little-r files.
• If my method is incorrect, I would appreciate guidance to address this issue.

Additionally, I have a question:

• Is running OBSGRID.exe mandatory for applying FDDA OBS-Nudging?
• Can I directly place the little-r files in the WRF directory and use them for OBS-Nudging without running OBSGRID.exe?

I would greatly appreciate any assistance to overcome this problem.

Looking forward to your guidance.

Thank you,
Naser