namelist.wps Era5 spin up

[Yiping]

Hello, I am planning to run WRF model to do sensitivity experiment. First step is that I need to simulate my rainfall cases with suitable parameterization.
I am confused with the issues listed below. Can anyone help me please?

I have a rainfall case (2016071101-2016071108). The red rectangle is my research area.

1. I have downloaded ERA5 data. Please see my down1.txt and down2.txt and namelist.wps. I download data from 2016071000-2016071123 and those data as my input era5 data:
./link_grib.csh /yyp/run_test/era5data/* (are my ERA5 data and namelist.wps reasonable to simulate my case?)

2. This is my start and end data. I set the same time for d01 and d02, but I have seen other tutorials which the d01 and d02 time are different. Why?
start_date = '2016-07-10_20:00:00', '2016-07-10_20:00:00',
end_date = '2016-07-11_12:00:00','2016-07-11_12:00:00',

3. After simulating my rainfall cases, I would like to do a sensitivity experiment. I will multiply 0.7 to my wind speed to identify the effect of low-level jet. How should I proceed? Which data should I modify?

4. If I want to keep my initial field unchanged but my lateral boundary field changed, which data should I modify?

Thank you so much for your help in advance!

 

[Ming Chen]

Please see my answers below:

1. I have downloaded ERA5 data. Please see my down1.txt and down2.txt and namelist.wps. I download data from 2016071000-2016071123 and those data as my input era5 data:
./link_grib.csh /yyp/run_test/era5data/* (are my ERA5 data and namelist.wps reasonable to simulate my case?)

This looks fine to me.

2. This is my start and end data. I set the same time for d01 and d02, but I have seen other tutorials which the d01 and d02 time are different. Why?
start_date = '2016-07-10_20:00:00', '2016-07-10_20:00:00',
end_date = '2016-07-11_12:00:00','2016-07-11_12:00:00',

They can be same or different. if you want the child domain run to start at a later time than that of the parent domain, you can set the start_data of D02 different to that for D01.

3. After simulating my rainfall cases, I would like to do a sensitivity experiment. I will multiply 0.7 to my wind speed to identify the effect of low-level jet. How should I proceed? Which data should I modify?

Please modify your met-em files, then rerun real.exe.

4. If I want to keep my initial field unchanged but my lateral boundary field changed, which data should I modify?

In this case you can save your initial data, then change met_em files and run real.exe again, which will produce wrfbdy as you expected.
When running wrf.exe, use the unchanged wrfinout you save previously and the newly generated wrfbdy.

 

[Yiping]

Thank you so much!

 

[Yiping]

Please see my answers below:

1. I have downloaded ERA5 data. Please see my down1.txt and down2.txt and namelist.wps. I download data from 2016071000-2016071123 and those data as my input era5 data:
./link_grib.csh /yyp/run_test/era5data/* (are my ERA5 data and namelist.wps reasonable to simulate my case?)

This looks fine to me.

2. This is my start and end data. I set the same time for d01 and d02, but I have seen other tutorials which the d01 and d02 time are different. Why?
start_date = '2016-07-10_20:00:00', '2016-07-10_20:00:00',
end_date = '2016-07-11_12:00:00','2016-07-11_12:00:00',

They can be same or different. if you want the child domain run to start at a later time than that of the parent domain, you can set the start_data of D02 different to that for D01.

3. After simulating my rainfall cases, I would like to do a sensitivity experiment. I will multiply 0.7 to my wind speed to identify the effect of low-level jet. How should I proceed? Which data should I modify?

Please modify your met-em files, then rerun real.exe.

4. If I want to keep my initial field unchanged but my lateral boundary field changed, which data should I modify?

In this case you can save your initial data, then change met_em files and run real.exe again, which will produce wrfbdy as you expected.
When running wrf.exe, use the unchanged wrfinout you save previously and the newly generated wrfbdy.

Dear Ming, sorry for bothering you again!
In terms of the answer 3: Please modify your met-em files, then rerun real.exe.
Should I modify met_em d01 or met_em d02 or both?
Thank you so much for your help in advance!

 

[aurorrmok]

Please see my answers below:

1. I have downloaded ERA5 data. Please see my down1.txt and down2.txt and namelist.wps. I download data from 2016071000-2016071123 and those data as my input era5 data:
./link_grib.csh /yyp/run_test/era5data/* (are my ERA5 data and namelist.wps reasonable to simulate my case?)

This looks fine to me.

2. This is my start and end data. I set the same time for d01 and d02, but I have seen other tutorials which the d01 and d02 time are different. Why?
start_date = '2016-07-10_20:00:00', '2016-07-10_20:00:00',
end_date = '2016-07-11_12:00:00','2016-07-11_12:00:00',

They can be same or different. if you want the child domain run to start at a later time than that of the parent domain, you can set the start_data of D02 different to that for D01.

3. After simulating my rainfall cases, I would like to do a sensitivity experiment. I will multiply 0.7 to my wind speed to identify the effect of low-level jet. How should I proceed? Which data should I modify?

Please modify your met-em files, then rerun real.exe.

4. If I want to keep my initial field unchanged but my lateral boundary field changed, which data should I modify?

In this case you can save your initial data, then change met_em files and run real.exe again, which will produce wrfbdy as you expected.
When running wrf.exe, use the unchanged wrfinout you save previously and the newly generated wrfbdy.

Dear Ming, Thank for you useful information!
In terms of the answer 3: Please modify your met-em files, then rerun real.exe.
I would like to do a sensitivity experiment too. I will multiply 2 to my wind speed to identify the effect on precipitation. I also use ERA5 data as meteorological data input. Can I multiply 2 to my ERA5 wind speed surface and presseure data instead of modifying my met-em files
? Thank you.

 

[Ming Chen]

Dear Ming, sorry for bothering you again!
In terms of the answer 3: Please modify your met-em files, then rerun real.exe.
Should I modify met_em d01 or met_em d02 or both?
Thank you so much for your help in advance!

You should modify all met_em.d01 files and the met_em.d02 file at the initial time. This is because you need to create wrfinput_d01 and wrfbdy_d01 for the parent domain, and you only need to create wrfinput_d02 for your child domain.

 

[Ming Chen]

Dear Ming, Thank for you useful information!
In terms of the answer 3: Please modify your met-em files, then rerun real.exe.
I would like to do a sensitivity experiment too. I will multiply 2 to my wind speed to identify the effect on precipitation. I also use ERA5 data as meteorological data input. Can I multiply 2 to my ERA5 wind speed surface and presseure data instead of modifying my met-em files
? Thank you.

Please clarify what you intend to do. I am not quite sure ....

 

[Yiping]

met_em.d02 file at the initial time

You should modify all met_em.d01 files and the met_em.d02 file at the initial time. This is because you need to create wrfinput_d01 and wrfbdy_d01 for the parent domain, and you only need to create wrfinput_d02 for your child domain.

Thank you for your answer! I am still a bit confused. I modified all the met_em files including d01 and d02. and rerun to get wrfinput_d01, wrfinput_d02, wrfbdy_d01. "You should modify all met_em.d01 files and the met_em.d02 file at the initial time". what does at the initial time mean?

 

[Yiping]

Thank you for your answer! I am still a bit confused. I modified all the met_em files including d01 and d02. and rerun to get wrfinput_d01, wrfinput_d02, wrfbdy_d01. "You should modify all met_em.d01 files and the met_em.d02 file at the initial time". what does at the initial time mean?

Why not modify all the met_em d02 files?

 

[aurorrmok]

Please clarify what you intend to do. I am not quite sure ....

I apologize for any confusion I may have caused. I am now using WRF3.9 to simulate the precipitation and I using ERA5 grib data as input. Then I want to double the wind speed in the initial meteorological field. Should I use the original ERA5 data as input and then modify all met_em.d01 files and the met_em.d02 file? Or should I directly multiply the ERA5 wind speed data by 2 without modifying the met files? Thank you.

 

[Ming Chen]

Why not modify all the met_em d02 files?

Because these met_em.d02 files are not used. We only use met_em.d01 to produce wrfbdy data.

 

[Ming Chen]

I apologize for any confusion I may have caused. I am now using WRF3.9 to simulate the precipitation and I using ERA5 grib data as input. Then I want to double the wind speed in the initial meteorological field. Should I use the original ERA5 data as input and then modify all met_em.d01 files and the met_em.d02 file? Or should I directly multiply the ERA5 wind speed data by 2 without modifying the met files? Thank you.

You can either double winds in ERA5 or double winds in met-em files. I suppose the effect is the same.

 

[Yiping]

Because these met_em.d02 files are not used. We only use met_em.d01 to produce wrfbdy data.

Thank you! So when it comes to modify met_em files, what I should do is to change all the met_em d01 files to generate new wrfinputd01 and wrfibdyd01 and modilfy the first date of met_em d02 to generate the wrfinputd02?

I suppose that the result would be the same if your change all the met_emd01 and met_emd02. Is this correct?

For example, I first generate the wrfinputd01 and wrfinputd02 and wrfbdyd01. I then conduct my sensitivity experiment (which is multiply 0.7 to my wind speed)
1. make my initial field unchanged and lateral boundary field changed.
I save my wrfinputd01 and wfinputd02 and use my new generated wrfbdyd01 (by changing all the files in met_emd01).
2. make my initial field changed and lateral boundary field unchanged.
I save the wrfbdy01 and use the generated wrfinputd01 and wrfinputd02 (by changing first file of met_emd01 and first file of met_emd02).
3. make my initial field and lateral boundary field changed (by changing all the met_emd01 files and first file of met_emd02)
Are these correct?

Thank you very much for your help!
Have a great day ahead!