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[cenlinhe]

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[MoreblessingMuzava]

create_forcing.exe "No previous data" error for T2D with WRF Output (WRF-Hydro/HRLDAS)

Hello everyone,
I am attempting to generate HRLDAS forcing files from WRF (ARW) model output, but I am consistently encountering a "No previous data" error for the T2D variable when running create_forcing.exe.
The program does not crash, but it stops processing further variables, indicating it's not generating complete forcing files. I have performed extensive troubleshooting, and I'm hoping someone with specific knowledge of create_forcing.exe's internal workings or common incompatibilities might be able to offer guidance.

My Goal:
To successfully convert wrfout_d01_YYYY-MM-DD_HH:MM:SS files (containing 2m temperature as T2D) into HRLDAS forcing files using create_forcing.exe.

My System & Software Setup:

• Operating System: Ubuntu (presumably the version of your VM)
• WRF Version: WRF-ARW 4.5.2
• HRLDAS/WRF-Hydro Code: Cloned from the official Git repository
• Compiler: mpif90
• NetCDF Libraries: Installed at /opt/wrf_libs/netcdf/ (including libnetcdf and libnetcdff). These were explicitly linked during create_forcing.exe compilation.

The Problem:

When I run ./create_forcing.exe, it initializes, reads geo_em.d01.nc, identifies the start date, but then prints "No previous data" for the T2D variable and does not proceed to process other variables.
Exact create_forcing.exe Output:

 Forcing type: 1                                                                                                                              
 2|100|1000|0|T2|K|"2m Temperature"|0|0|0|100
 ... (other variable listings)
 geo_em_flnm     = "/opt/wrf_libs/WPS/geo_em.d01.nc"
  flnm = /opt/wrf_libs/WPS/geo_em.d01.nc
 Done with subroutine read_geo_em_file
 Date = 2019-03-15_00  ihour =            0
 Field label= T2D
 No previous data.

Troubleshooting Steps Taken (and their Results):
I have thoroughly checked the following:

1. WRF Output File Variable Naming:
   • Initially, the 2m temperature variable in wrfout files was T2.
   • I successfully renamed T2 to T2D in all wrfout files using ncrename -v T2,T2D. ncrename reported success.
2. Verification of T2D Existence in wrfout Files:
   • ncdump -h wrfout_d01_2019-03-15_00:00:00 | grep "T2" (and for other files) now clearly shows float T2D(...).
   • The :history attribute in the wrfout files confirms the ncrename operation was successful.
3. Verification of T2D Data Content:
   • ncdump -v T2D -f c wrfout_d01_2019-03-15_00:00:00 confirms that the T2D variable contains valid numerical data (e.g., T2D = 292.4706, 292.2442, ...). The data is not missing or malformed according to ncdump.
4. namelist.input Configuration for create_forcing.exe:
   • The namelist.input (located in HRLDAS_forcing/) correctly specifies the DataDir as /opt/wrf_libs/WRF-4.5.2/run/ where the wrfout files reside.
   • startdate (2019-03-15_00:00) and enddate (2019-03-17_12:00) are set.
   • The Tfile_template matches the wrfout filename format: 'wrfout_d01_%Y-%M-%D_%H:00:00'.
5. create_forcing.exe Compilation:
   • I performed a make clean followed by make within the HRLDAS_forcing/ directory.
   • Compilation was successful, explicitly linking against /opt/wrf_libs/netcdf/lib and using /opt/wrf_libs/netcdf/include.
   • A minor tmpnam warning from Jasper was observed but is non-fatal.
6. File Permissions:
   • ls -l /opt/wrf_libs/WRF-4.5.2/run/wrfout_d01_2019-03-15_00:00:00 shows rw-rw-r-- permissions for the ubuntu user, confirming read access.

My Question:

Given that all checks on the input files and compilation seem correct, what could be causing create_forcing.exe to report "No previous data" for T2D? Are there any known subtle incompatibilities with specific NetCDF versions from WRF output, or internal assumptions within create_forcing.exe that I might be missing?

Any insights or suggestions would be greatly appreciated. Thank you for your time.

[cenlinhe]

create_forcing does not work for wrfout files. You have to modify the source code in create_forcing.F file to make it work. However, since you already have wrfout files, you could simply write a python/matlab/ncl script to extract the forcing variables from your wrfout file and interpolate them into your HRLDAS grids (if your HRLDAS grid is different from WRF), and then generate the HRLDAS forcing files. You do not need to use create_forcing in this case.