V4 REAL rejecting OBSGRID analyses

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RCarpenter
Posts: 49
Joined: Tue Jun 12, 2018 11:18 pm

V4 REAL rejecting OBSGRID analyses

Post by RCarpenter » Wed Jun 20, 2018 2:59 pm

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?

davegill
Posts: 90
Joined: Mon Apr 23, 2018 9:03 pm

Re: V4 REAL rejecting OBSGRID analyses

Post by davegill » Fri Jun 22, 2018 2:58 pm

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 met_em.d01.2018-06-20_12:00:00.nc | grep TITLE
:TITLE = "OUTPUT FROM METGRID V3.5.1" ;
```
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.
Dave Gill
NCAR/MMM

RCarpenter
Posts: 49
Joined: Tue Jun 12, 2018 11:18 pm

Re: V4 REAL rejecting OBSGRID analyses

Post by RCarpenter » Wed Jun 27, 2018 8:49 pm

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: ".

Thanks.

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