Merging ERA5 Atmospheric IC and NLDAS2 IC for WRF/MPAS

[yibssss]

Hi everyone!

I'm trying to do a regional WRF/MPAS simulation with all the Initial Condition from ERA5 and just the soil moisture and soil temperature IC from NLDAS2.
For example: having the U, V, TT, SPECHMD, SOILHGT, etc.... from ERA5, and having the SOILTxxx and SOILMxxx from NLDAS2 for the WRF/MPAS run
That is only for the IC, all the following LBC conditions can be/are from ERA5.

Is it possible at all? and if so, what is the best route to accomplish it?
I have attempted editing 1st met_em file and xxx_static.nc generated from only ERA5 with remapped NLDAS2 ST and SM to the respective grid. Also changed the netcdf attributes and the soil depth from the ERA5 layers to NLDAS-2 (noah)'s layer depth. But these runs all crashed with SEGMET error several timestep in .
NASA doesn't provide NLDAS2 Grib format anymore so creating a vtable for NLDAS2 and using ungrib.exe route can't be done neither . I thought about editing the WPS intermediate file directly but have not figure anything out yet.

Thanks Everyone!

 

[kwerner]

Hi, In what format is the NLDAS2 data provided? It is typically possible to use two different data sources. See this section in the WRF Users' Guide, which overviews the process, and this section goes over how to write data to the intermediate file format. Once you get the data files into the intermediate format, you will then run metgrid again to include both types of data in the met_em* files.

 

[yibssss]

NLDAS2 is provided in nc datasets! So, I should attempt to write the NLDAS2 nc dataset into intermediate file with the Fortran write example above, and then metgrid can handle the ERA5 and NLDAS2 intermediate file correctly. Is that right?

And what about MPAS! Can Init_atmosphere also process multiple intermediate files like metgrid? Thanks!

Hi, In what format is the NLDAS2 data provided? It is typically possible to use two different data sources. See this section in the WRF Users' Guide, which overviews the process, and this section goes over how to write data to the intermediate file format. Once you get the data files into the intermediate format, you will then run metgrid again to include both types of data in the met_em* files.

 

[kwerner]

So, I should attempt to write the NLDAS2 nc dataset into intermediate file with the Fortran write example above, and then metgrid can handle the ERA5 and NLDAS2 intermediate file correctly. Is that right?

Yes, that is correct.

And what about MPAS! Can Init_atmosphere also process multiple intermediate files like metgrid? Thanks!

Yes, MPAS can use the same intermediate files that WRF uses.