Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

V4 REAL rejecting OBSGRID analyses

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.


I am using the OBSGRID metoa_em files as input to REAL. In v4, I get this error:

d01 2018-06-20_12:00:00 This input data is not V4: OUTPUT FROM OBSGRID

It appears that REAL is rejecting any METGRID netCDF files that don't have "V4" in the TITLE attribute.

As a workaround, I am setting force_use_old_data=T in the time_control record of the namelist.input file.

So, is this a bug or a feature?
This is an error that we have introduced in the WRF system. As a temporary fix, go into the share/input_wrf.F file. Towards the very bottom of that file, there is a new subroutine that tries to determine if a user is attempting to bring in old data. Look for this code segment:
1876 IF ( &
1877 ( INDEX(TRIM(input_title_char),'METGRID' ) .NE. 0 ) .OR. &
1878 ( INDEX(TRIM(input_title_char),'SFCFDDA' ) .NE. 0 ) .OR. &
1879 ( INDEX(TRIM(input_title_char),'EMISSIONS' ) .NE. 0 ) .OR. &
1880 ( INDEX(TRIM(input_title_char),'XYZZY' ) .NE. 0 ) &
1881 ) THEN
With your output from obsgrid, issue a command similar to this:
> ncdump -h | grep TITLE
Take a unique part of that string and include that as an exception in the input_wrf.F file. Then recompile. If this works, let us know and we will include this in the next bug fix release.
Adding this line solved the problem:

( INDEX(TRIM(input_title_char),'OBSGRID' ) .NE. 0 ) .OR. &

I'd also suggest changing the message from "Yes, this special data is acceptable to use: " to something like "Skipping rigorous check for: ".