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problem with moving nest(vortex_following)

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ray96yelei

Member
Hello, I use wrf model with vortex following option to slmulate a tropical cyclone case, and follow the webpage, eg. https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=45&t=8731&p=15417&hilit=moving+nest#p15417
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=45&t=8696&p=15244&hilit=moving+nest#p15244
https://forum.mmm.ucar.edu/phpBB3/viewtopic.php?f=45&t=8731&p=15417&hilit=moving+nest#p15417
To simulate it better, I use wrf with vortex following, sst_update, nudging fdda, and I also add high-res terrain and landuse data, and change it to USGS in wps namelist, but I didnot get the successful simulation, there is an error in rsl.error.0000, and the simulation stops at early stage.
can you give me some help?
 

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Hi,
You are trying a lot of options at one time with this simulation. We typically recommend taking things slowly (baby-steps). Unfortunately the sst-update option does not work correctly with vortex-following. Although the case will likely run without errors, the update is only modified by the wrflowinp file, and since you are unable to create that file for a vortex-following case, then there is no method to do this for the nest. I suspect that nudging may be the same, but I'm not certain. I would suggest taking these steps to trouble-shoot this.
1) turn off sst-update
2) turn off nudging
Then re-run to see if anything changes. If not, then please attach the namelist.input file, as well as the rsl* files. You can combine the rsl files in a single *.TAR file.

Thanks!
 
Thank you for your reply.
I also see a ppt file about moving nest set on wrf user page, is these set correct and required in moving nest set? maybe it is somehow different from wrf user guide.
 

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No, all those options are not mandatory. Can you send me the link to the web page where it links to the ppt file? I'd like to see where this is coming from. Thanks!
 
link to https://www2.mmm.ucar.edu/wrf/users/hurricanes/moving_nest.html
https://www2.mmm.ucar.edu/wrf/users/tutorial/tutorial_presentation_for_hurricanes.html
and I have some questions about simulation.
First, I use fixed nest (basic option) to simulate a tropical cyclone case, based on the default namelist, I add the sst_update and fdda nudging step by step, and finally get the wrfout file.
Then I want to use moving nest (vortex following option) to simulate it, I want to know what exactly should I add in the namelist?
Following with the wrf user guide, I add namelist variables :vortex_interval, max_vortex_speed, corral_dist, track_level, time_to_move, in the &domains section, but the tc track is so different and wrong. SO I AM CONFUSED.
AND THERE ARE SOME QUESTION:
1. simulation time is about 10 days, and it maybe too long, how does the simulation ability change with simulation time duration?
2.is it enough to add above 5 namelist variables in the &domain section?
3.should I add sst_update or fdda nudging in the moving nest or not?
4.could you please provide me with some namelist.input file which simulate tc successufully? I can follow them to add or edit namelist. THANK YOU.
 
Hi,
I'll try to answer your questions below:
1) The longer the model is run, the more error that can occur, which could make the results worse. Is there a known tropical cyclone (or area of low pressure) for the full 10 days? You typically only need about 24 hours of spin-up time prior to the time of the event, so keep that in mind.
2) The above 5 namelist options are not mandatory. In fact, take a look at a practice vortex-following case we provide to students at the WRF tutorial (https://www2.mmm.ucar.edu/wrf/OnLineTutorial/Class_Jan2020/cases/vortex.php). None of those options are mentioned and the simulation is still successful as a vortex-following simulation. You can use the file WRF/test/em_real/examples.namelist to see the options you are adding and the recommended values, and you can also use the file WRF/test/em_real/README.namelist to look at the descriptions of those variables to see if you think you need them.
3) No, you should not add sst_update or fdda to the namelist.
4) See the namelist in the tutorial practice example mentioned in #2 above. It may also help if you attach your namelist so that we can take a look at what you're set-up looks like.
 
Thank you so much. Following your advice, I successfully get the wrfout result. But I still need to adjust the namelist because I mostly use default set in namelist.
And I have some question about WPS which I cannot find in the WRF user guide, could you please help me? Thank you.
1.what should I edit "geog_data_res=" in the geogrid section of the namelist.wps?
should I use geog_data_res = 'default','default','default','default', or geog_data_res = '10m','5m', '2m', '30s', ?
2.which vtable file should match the era5 pressure levels and single levels data?
should era5 pressure levels and single levels data both use same Vtable.ERA-interim.pl or they respectively use different other vtable file?
Thank you.
 
Hi,
1. This depends on the version of WPS you are using. If you are using a version 3.8 or newer, then 'default' is what you should use. If it's an earlier version, the expected value is 10m, 5m, 2m, 30s.
It's best to always start with the default namelist and make changes from that - then you know what the default expected values are.
Perhaps this web page will also be helpful: https://www2.mmm.ucar.edu/wrf/users/namelist_best_prac_wps.html

2. I believe the correct Vtable for ERA-5 data is the Vtable.ERA-interim.pl file (if your data are on pressure levels).
 
Thank you for your reply.
For the 2nd answer, which vtable should era5 data on single level use?
Does single level data use Vtable.ERA-interim.pl too?

And I also found that after using same era5 data running ungrib.exe and metgrid.exe, met_em.d0* file in v4.0 is much smaller size than v3.9.1 and v3.8, is that right? And met_em.d0* file in v3.9.1 or v3.8 is the basically same size.

Thank you
 
Hi,
Regarding the Vtable, what do you mean by single level? Do you only have 1 level of data?
I'm not really sure which Vtables to specifically use for different types of data. I would recommend reaching out to the RDA group at NCAR. They manage all of the data, where our department just focuses on the model.

I believe starting with V4, there were some compression components added to the code that may contribute to the size difference. I would suggest taking a look at the met_em* files to see if they look okay. Make sure they have all the data at all levels. You could even run them through real.exe to make sure they run there.
 
Thank you for your reply.
recently i want to use tc bogus, could you please provide some case practice with me to learn and use it? web page or pdf both ok
Thank you.
 
We don't have any example practice cases for TC Bogus, as it's not something we test or use often. You can find some information from our Users' Guide in Chapter 10: https://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/v4.2/users_guide_chap10.html#TCBogus
There is also a bit of information in the file WRF/test/em_real/examples.namelist
 
Thank you for your reply. Here are steps of running tc.exe from WRF User Guide:
1) Run all of the WPS programs as normal (geogrid, ungrib, and metgrid).
2) As usual, link-in the metgrid output files into either the test/em_real or the run directory.
3) Edit the namelist.input file for usage with the tc.exe program. Add-in the required fields from the &tc record, and only process a single time period.
4) Run tc.exe
5) Rename the output file, auxinput1_d01_<date> to the name that the real.exe program expects, met_em.d01.<date>, note that this will overwrite your original metgrid.exe output file for the initial time period.
6) Edit the namelist.input file to process all of the time periods for the real.exe program.

And I have some questions about them. Could you please help me to answer it? Thank you.
1.for step1), does it need to build WPS in serial option? or is it both ok in dmpar?
2.for step1),how many domain does it should be in WPS. eg, I want to use 3domain with vortex_following option, how many domain should i set in WPS?
3.for step3),must the input to the tc.exe program be a single time-period and single domain of metgrid data?
4.for step3),eg, with 3 domains, how to horizontally-interpolate the generated meteorological fields to the fine-grid domains?
5.for step5), I donot know exactly about this step. does it mean that the output file is auxinput1_d01_<date>?
6.for step6), what option does it should build with the real.exe program, serial or dmpar? eg. I build WRF in dmpar,vortex and WPS in dmpar. Then, to use tc.exe, I build a new WRF in serial,vortex and WPS in serial. which WRF and WPS should I use in different step?

Or I want to use 3 domains(2 nest domain) with vortex_following option, and tc bogus option, what should i do in every step? Thank you.
 
1) It doesn't matter whether WPS is built in serial or dmpar.
2) For the purpose of vortex-following, you only need to run a single domain in WPS (see: https://www2.mmm.ucar.edu/wrf/OnLineTutorial/Class_Jan2020/cases/vortex.php)
3) It does not matter how many domains or time periods of met_em* files you have. The program will only process the 1 time period for a single domain.
4) If you're using vortex-following, this will be done when running real.exe
5) When you run tc.exe, you will get an output file called something like "auxinput1_d01_<date>." You'll need to rename that file to "met_em.d01_<date>" where the "date" is the same date as the start of your run, and of the auxinput1* file.
6) I don't *think* it will matter which one you use, but you can test this out. If you get an error, use the other one!
 
Thank you for your reply. Here are Helpful hints for tc bogus from example.namelist under WRF/test/em_real:
1) The TC bogus *MUST* only be run with a single processor: serial (with or without a nest build option), or as a DM build with np=1.
2) Run the TC program for only the initial model time. Remember to copy your metgrid file to a safe location and then let the TC scheme generate the auxiliary files.
3) The TC program does not handle soil moisture or soil temperature correctly. After running the TC program, use an NCL script to put the modified fields back into the original metgrid file (remember that you are keeping a pristine copy elsewhere). The modified fields to copy are: "RH", "TT", "UU", "VV", "GHT", "PRES", "PMSL", "PSFC".
4) The TC program runs quickly, only a few seconds. It is a good idea to process multiple runs, and vary the TC initialization. It would be reasonable to select the maximum wind speed (vmax_meters_per_second) from 30 to 60 by 5, select the radius of maximum winds ((m), rmax) = 50000 to 200000 by 50000, and select a tuning parameter for the vortex (vmax_ratio) = 0.5 to 0.9 by 0.1. Look at the resulting bogus storms (sea level pressure, surface wind speeds, and overall storm size), and choose the best.
5) Remember to also consider starting the TC program at a later or earlier time during your parameter space exploration.
6) The bogus storm will organize better if the initialization of the tropical storm is entirely over water, and if the storm is able to develop over water for several days.
7) After the metgrid file is finalized, and the real program is run, use DFI in WRF. Removing and then introducing an entire bogus typhoon is the definition of unbalanced. Running DFI for 2-3 hours back and forth will be a benefit. For a successful implementation of a TC bogus storm in WRF, the storm should not oscillate in size, should not be radiating massive amounts of gravity waves, and should not rapidly weaken.

And I have some questions about them, could you please help me to answer? Thank you.
1.For hint 3), how to use an NCL script to put the modified fields back into the original metgrid file？ could you please provide the ncl script?
2.For hint 5), I donot understand starting the TC program at a later or earlier time during your parameter space exploration? can you explain it?
does it mean the start time in namelist.wps and namelist.input?
3.For hint 7), what is DFI? I donot know about it.
Besides, eg, can I run tc.exe to remove a tropical cyclone at first, then run tc.exe again to insert a tropical cyclone, and then run real.exe and wrf.exe?
 
Hi,
1) You will need to post a question to the NCL section of this forum for specifics about the NCL program. Another member of our team is the specialist for that post-processor.
2) I suppose you could run the tc.exe program for some time later than (or earlier than) the start date/time of your wrf simulation. I'm not aware of the benefits of this, though, as I've never done much testing with the tc.exe program.
3) You can read about DFI here: https://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/v4.2/users_guide_chap5.html#DFI

Are you actually planning to use the tc bogus option for your research, or are you simply playing around with it to learn about it?
 
Hello professor, thank you for yourreply.
I really want to use the tc bogus option to simulate the topical storm better.
And I use tc bogus following the WRF User Guide description:
5) Rename the output file, auxinput1_d01_<date> to the name that the real.exe program expects, met_em.d01.<date>, note that this will overwrite
your original metgrid.exe output file for the initial time period.
6) Edit the namelist.input file to process all of the time periods for the real.exe program.

When I run real.exe, there are some errors in rsl.error.0000 file.
But I really use WRF V4.0 both in WPS step, tc.exe step and real.exe step.
And tc.exe is no_nesting optiong, real.exe is vortex_following option in configure step.
And following step 5) in WRF USER GUIDE, i directly rename the auxinput1 file to met_em. file for initial time.
what is the reason, could you please give some help? thank you.

Besides, I have another question about vortex_following option. I respectively generate metgrid file with 1 domain and 3 domains at WPS step, and both max_dom=3 in namelist.input, and then run real.exe and wrf.exe. I find that grep ATCF rsl.out after WRF step with met_em file with 1 domain and 3 domains(both max_dom=3 in wrf namelist.input), the ATCF result are a little different, not entirely same.
 

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It may be that the code in the tc bogus program was not updated with the V4.0 release, nor since then. That seems hard to believe, but so few people use this option that it's possible it was overlooked. As the message indicates, for now, you can try to just use the option force_use_old_data = .true. in the &time_control section to see if that will enable you to get past that error.

As for your second question, I'm confused about your method. Are you saying that you sometimes run vortex following with metgrid input files from all 3 domains? If so, you should not be doing that. You should only need to use d01.
 
Thank you for your reply, I appreciate.
After some simulation tests with 3 domains moving nest(max_dom =3), I find that the result by dom=3 in WPS(3 domain met_em file, after running real.exe gets 3domain wrfinput) is more close to best track data than the result by dom=1 in WPS(1 domain met_em file, after running real.exe gets 1domain wrfinput). but once you told me I should set dom=1 in WPS. But the result is not good.
And now I using specified moving nest with preset move option, but have some problem about namelist.input option. following the WRF USER GUIDE, after running real.exe always gets some errors, can you provide some learning site about preset or example namelist? Thank you.
 
Hi,
I guess you should use whichever way gives you the best results.

As for present moves, I don't have a sample namelist, but there is some information in the test/em_real/README.namelist file. Look for "Namelist variables for controlling the specified moving nest" and there are a few options there.
 
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