Problem with grib output at sub hour period

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alainF
Posts: 37
Joined: Fri Apr 19, 2019 8:12 am

Problem with grib output at sub hour period

Post by alainF » Thu Oct 22, 2020 7:06 pm

Hello,
I run run_unipost_minutes, and it produces the grib outputs from the wrfout files.
But when I want to read the grib output files, I have an error. The program such as panoply or whatever else it is, cannot read the file. Such problem only happens with mid-hour 30 minutes outputs, not for round hour output. I have attached an example of such faulty file. Is there a problem with the time syntax inside the grib file ? WRFPRS_d03.16_30 can't be read, but it is ok with WRFPRS_d03.16_00.
I must also say that, using ncview <mywrfout_file@16h30> displays the meteorological fields. So I guess that the original wrfout file is not corrupted.
Thank you for your help,
Attachments
WRFPRS_d03.16_00.txt
(28.34 MiB) Downloaded 14 times
WRFPRS_d03.16_30.txt
(28.38 MiB) Downloaded 16 times
run_unipost_minutes.txt
(23.21 KiB) Downloaded 15 times

hertneky
Posts: 63
Joined: Tue May 12, 2020 4:18 pm

Re: Problem with grib output at sub hour period

Post by hertneky » Mon Oct 26, 2020 4:31 pm

We are aware of an issue in the code with the time-stamp for sub-hourly output, which causes issues reading files in some downstream applications. This has only been an issue for accumulated and time-averaged fields and has been observed for both grib1 and grib2 output. This was first discovered with V3.2 and does not have a fix at this time. I can take a look at your particular issue to see if I can find a solution for you. Looking at wgrib output for the data you shared I see (using APCP as an example; 'wgrib -V WRFPRS_d03.16_00.txt | grep APCP -A6'):

16:00 file

rec 308:25304096:date 2020102206 APCP kpds5=61 kpds6=1 kpds7=0 levels=(0,0) grid=255 sfc 0-16hr acc:
APCP=Total precipitation [kg/m^2]
timerange 4 P1 0 P2 16 TimeU 1 nx 265 ny 200 GDS grid 3 num_in_ave 0 missing 0
min/max data 0 6.1281 num bits 16 BDS_Ref 0 DecScale 4 BinScale 0

16:30 file

rec 308:25309802:date 2020102206 APCP kpds5=61 kpds6=1 kpds7=0 levels=(0,0) grid=255 sfc 960-990min acc:
APCP=Total precipitation [kg/m^2]
timerange 4 P1 32 P2 33 TimeU 14 nx 265 ny 200 GDS grid 3 num_in_ave 0 missing 0
min/max data 0 7.7444 num bits 16 BDS_Ref 0 DecScale 4 BinScale 1

The 16:00 time has a 16 hour total accumulation, while the 16:30 time has a 30 min accumulation output, which looks to be wrong. It looks like you requested the 'accumulated total precip' (ACM TOTAL PRECIP) in your wrf_cntrl.parm since the max at 16:30 is larger than at 16:00, indicating the time stamp should be 0-990 mins for the 16:30 file. Is that right? Similar fields will have the same issue. It looks like the P1 timerange is getting set incorrectly. If you can share a sample 30 min wrfout file - that would be helpful for testing since I do no have any recent sub-hourly data to test with. Please let me know if the file is too large and you need ftp transfer instructions.

alainF
Posts: 37
Joined: Fri Apr 19, 2019 8:12 am

Re: Problem with grib output at sub hour period

Post by alainF » Tue Oct 27, 2020 9:21 pm

Hello,
Thank you to consider this problem.
The wrfout file is too large. I will need to do a ftp upload.
In the meantime, I send the corresponding grib output with the same time stamp and the parameter cntrl file. The forecast starts at 06Z.
It is not the same run compared to my previous post, because the previous results were erased.
Best Regards
Attachments
wrf_cntrl.parm.txt
(30.56 KiB) Downloaded 18 times
WRFPRS_d03.14_30.txt
(28.25 MiB) Downloaded 14 times

hertneky
Posts: 63
Joined: Tue May 12, 2020 4:18 pm

Re: Problem with grib output at sub hour period

Post by hertneky » Wed Oct 28, 2020 3:44 pm

Here are the instruction to ftp. Let me know if you have any issues.

ftp.rap.ucar.edu
login: anonymous
password: email address
*Note that the password is your actual email address, do not type in "email address".

cd /incoming/irap/upphelp
(warning)must use whole path or will not be visible

Make a directory using your first and last name

Before transferring your data, ensure you are in 'binary mode' if it is not already your default ftp transfer type.
If you are in ascii mode, type 'binary' on the command line to switch modes.
If you try to transfer data via ascii mode, it will likely become corrupt during the transfer.

Move your files under this newly created directory
(warning)filename may not contain ':' - rename wrfout files

Notify upp-help that your files are ready

alainF
Posts: 37
Joined: Fri Apr 19, 2019 8:12 am

Re: Problem with grib output at sub hour period

Post by alainF » Wed Oct 28, 2020 9:26 pm

I did as you said.
The file should be inside the directory upphelp,

Thank you

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