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I'm using the WRF model, and I'm going to ask you questions

dakyoung

New member
Hi I'm just learning WRF. I have a few questions, can anyone tell me?

I put both data as input data 2022-05-05_00:00:00 and 2022-05_06:00:00 to generate initial, boundary values with WPS and used it to run ./real.exe, ./wrf.exe.
(Run in a bidirectional nested model containing one input file, Domain 1 has a resolution of 1.5 km, Domain 2 has a resolution of 300 m, and Namelist_input has a &time_control of 10 minutes.) I attached the namelist.wps and namelist.input that I used.

As a result, wrfout_d01_2022-05_00:00 and wrfout_d02_2022-05_00:00 were generated. I have five questions here.

1. wrfout_d01_2022-05_00:00:00, wrfout_d02_2022-05_00:00:00 What exactly does this output data mean?
2. I set &time_control of namelist_input to 10 minutes, what does this value mean based on the output file?
3. I set the &time_control of the namelist_input to 10 minutes, but the less this value, the less accurate it is?
4. What is the difference between setting maxdom=1 in Namelist.wps, setting maxdom=2 in Namelist.input, setting maxdom=2 in Namelist.wps, and setting maxdom=2 in Namelist.input?
5. In the beginning, is it considered that the accuracy of the output value increases as the number of input data (GFS, FNL, etc.) that generate the boundary value is put in more?

Thank you.
 

Attachments

  • namelist.input
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  • namelist.wps
    1.3 KB · Views: 6
Please see my answers below:

1. wrfout_d01_2022-05_00:00:00, wrfout_d02_2022-05_00:00:00 What exactly does this output data mean?

These are wrfout files at the initial time of model integration.

2. I set &time_control of namelist_input to 10 minutes, what does this value mean based on the output file?

"run_minutes = 10" indicates the model will run for 10-minute integration, in your case, it will stop at 2022-05_00:00:00

3. I set the &time_control of the namelist_input to 10 minutes, but the less this value, the less accurate it is?

No. Please see my answer to your question 2.

4. What is the difference between setting maxdom=1 in Namelist.wps, setting maxdom=2 in Namelist.input, setting maxdom=2 in Namelist.wps, and setting maxdom=2 in Namelist.input?

max_dom must be same in namelist.wps and namelist.input. It tells how many domains are specified in your case.

5. In the beginning, is it considered that the accuracy of the output value increases as the number of input data (GFS, FNL, etc.) that generate the boundary value is put in more?

It is recommended to update the boundary as frequently as possible. So the answer is yes.
 
Please see my answers below:

1. wrfout_d01_2022-05_00:00:00, wrfout_d02_2022-05_00:00:00 What exactly does this output data mean?

These are wrfout files at the initial time of model integration.

2. I set &time_control of namelist_input to 10 minutes, what does this value mean based on the output file?

"run_minutes = 10" indicates the model will run for 10-minute integration, in your case, it will stop at 2022-05_00:00:00

3. I set the &time_control of the namelist_input to 10 minutes, but the less this value, the less accurate it is?

No. Please see my answer to your question 2.

4. What is the difference between setting maxdom=1 in Namelist.wps, setting maxdom=2 in Namelist.input, setting maxdom=2 in Namelist.wps, and setting maxdom=2 in Namelist.input?

max_dom must be same in namelist.wps and namelist.input. It tells how many domains are specified in your case.

5. In the beginning, is it considered that the accuracy of the output value increases as the number of input data (GFS, FNL, etc.) that generate the boundary value is put in more?

It is recommended to update the boundary as frequently as possible. So the answer is yes.

Thank you for your answer!

Can you give me a more specific description of the 2 &time_control of namelist_input (run_days, run_hours, run_minutes, run_seconds)?
Is the run time determined by the input file (GFS, FNL..) or is it okay to set it regardless of the input file time?

For example, if I put two 2022-05-05_00:00, 2022-05-05_06:00 as input files, do I have to set it to run_hours=6 or is it okay to set it to run_hours=1 or run_minutes=10?

I'm confused with the phrase "run_minutes = 10 indications the model will run for 10-minute integration, in your case, it will stop at 2022-05_00:00:00", what does it mean to stop at 2022-05-05_00:00:00?
 
Hi,
run_time specifies how long your case will run. For example, if you set
run_days =1
WRF will integrate for 1- day.
run_time has nothing to do with your input data (GFS, FNL, etc.)
The correct phase is:
"run_minutes = 10 indications the model will run for 10-minute integration, in your case, it will stop at 2022-05__05_10: 00:00" (sorry for the typo)
 
Thank you for your answer!!

If I set it as below in namelist.input, can I get the output of 1 hour? (Some variables are omitted)

---------------------------------------------------------------------
&time_control

run_hours =1,

start_year = 2022, 2022,
start_month = 05, 05,
start_day = 05, 05,
start_hour = 00, 00,


end_year = 2022, 2022,
end_month = 05, 05,
end_day = 05, 05,
end_hour = 06, 06,

history_interval = 60, 60,
frames_per_outfile = 1, 1,
---------------------------------------------------------------------
 
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