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Ungrib file lost isobaric levels

Tam Nguyen

New member
Dear all,

I'm currently running WRF with ERA5 for a few specific years. I've done a few test runs, which did fine. However, when I run with data from 1964, ungrib.exe produces FILE that lost levels in RH, TT, PRES,... The problem is that metgrid.exe and ungrib.exe stills run successfully without warning. I only found out when running real.exe and got "Trapping at x location."
When I ncdump the met_em files, I got a few variables without num_metgrid_level, and the MemoryOrder doesn't have verticle coordinates like this:
float RH(Time, south_north, west_east) ;
RH:FieldType = 104 ;
RH:MemoryOrder = "XY " ;
RH:units = "%" ;
RH:description = "Relative Humidity" ;
RH:stagger = "M" ;
RH:sr_x = 1 ;
RH:sr_y = 1 ;

I'm using the Vtable.ECMWF, therefore should not be different between the files I run for this time period and others.

I have checked my input grib file, which has the full 33 levels like I've requested, and tried to run ungrib.exe again a few times but this issue remains.

I've attached below my namelist.wps in WPS, namelist.input in WRF/test, ncdump_test file which detailed one of met_em files, list input files of 1964.


  • ncdump_test.txt
    21.6 KB · Views: 1
  • namelist.input
    4.5 KB · Views: 0
  • namelist.wps
    960 bytes · Views: 0
  • list of variables.txt
    1.3 KB · Views: 3
  • read_test.txt
    43.4 KB · Views: 2
Where did you download the ERA5 data of 1964? Can you upload a single ERA file that has the level issue?
Dear Ming Chen,
I download the ERA5 data from the main website. I have attached the ERA file for temperature in pressure levels. Since a single file is quite big, I have separated it into 2 parts since it's convenient to download through API.

Temperature (first half): temperature_1964_a.grib
Temperature (second half): temperature_1964_b.grib

Best regards,
It seems that for the datafile you have, a single file contains multiple times of data. WPS will have trouble to process such datafile. Usually WPS can only process files that contain data at single time.
Dear Minh Chen,
I also understand that situation. However, when I run the same type of files for other time period, there's no such error occurring so I'm quite curious why it happens to only this year.