[gradsusr] Problem reading sub-hourly WRF grib files (NCEP code table for 15/30 min records)
Wesley Ebisuzaki - NOAA Federal
wesley.ebisuzaki at noaa.gov
Sun Nov 19 19:52:34 EST 2017
Ivan,
Back from a conference. 14 = 1/2 hour for grib1. However
there isn't a 1/2 hour time unit for grib2.
http://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_table4-4.shtml
The code needs to be changed to use minutes as the grib2 time units.
Note: grib1 only used 1 byte or 2 bytes to store the forecast length.
Therefore they invented a large number of time units. Grib2 uses
4 bytes to store the number of time units.
You can try to convince NCO to fix cnvgrib. I know the person
responsible for cnvgrib and good luck.
My suggestion #1 doesn't work
$ wgrib2 wrfprs_d01.00_30.g2 -if ":30 min fcst:" -set_ftime "30 min fcst"
-fi -grib wrfprs_d01.00_30.g2.con
add_time: undefined time unit 14
add_time: undefined time unit 14
add_time: undefined time unit 14
-if ":30 min fcst:" will always fail because wgrib2 doesn't understand the
time code 14.
The error message "add_time: undefined time unit 14" comes from the
calculation of
the verification time.
Wesley
On Fri, Nov 17, 2017 at 3:34 AM, Ivan Toman <ivtoman at inet.hr> wrote:
> Wesley,
>
> I think this comes from here:
>
> On grib1 output from UPP - this is for 10min record, all normal:
>
> $ wgrib WRFPRS_d01.00_10
> 1:0:d=17111700:RWMR:kpds5=170:kpds6=109:kpds7=1:TR=10:P1=0:P2=10:TimeU=0:hybrid
> lev 1:10min fcst:NAve=0
> 2:44496:d=17111700:SNMR:kpds5=171:kpds6=109:kpds7=1:TR=10:P1=0:P2=10:TimeU=0:hybrid
> lev 1:10min fcst:NAve=0
> 3:88992:d=17111700:REFC:kpds5=212:kpds6=200:kpds7=0:TR=10:P1=0:P2=10:TimeU=0:atmos
> col:10min fcst:NAve=0
> ...
>
> however, for 30min record:
>
> $ wgrib WRFPRS_d01.00_30
> 1:0:d=17111700:RWMR:kpds5=170:kpds6=109:kpds7=1:TR=10:P1=0:P2=1:TimeU=14:hybrid
> lev 1:30min fcst:NAve=0
> 2:44496:d=17111700:SNMR:kpds5=171:kpds6=109:kpds7=1:TR=10:P1=0:P2=1:TimeU=14:hybrid
> lev 1:30min fcst:NAve=0
> 3:88992:d=17111700:REFC:kpds5=212:kpds6=200:kpds7=0:TR=10:P1=0:P2=1:TimeU=14:atmos
> col:30min fcst:NAve=0
> ...
>
> TimeU=14
>
>
> Where this comes from?
>
> As far as I understand it, UPP follows this time designation for time
> units:
> http://www.nco.ncep.noaa.gov/pmb/docs/on388/table4.html
> 14 = "Half an hour"
>
> This is from UPP code that sets it:
>
> ! J. HALLEY GOTWAY, MODIFY HOW THE TIME INFORMATION IS STORED IN
> ID(17-20),
> ! (FCST TIME UNIT, P1, P2, TIME RANGE INDICATOR).
> ! CHECK IF THE NUMBER OF FORECAST MINUTES IS ZERO FOR HOURS OR NON-ZERO
> FOR
> ! OFF-HOUR FORECASTS. FOR OFF-HOUR FORECASTS, CHECK IF THE TOTAL NUMBER
> ! OF MINUTES IS DIVISIBLE BY 30, 15, OR NEITHER, AND USE THE APPROPRIATE
> ! FCST TIME UNIT VALUE. FOR ANY FIELD OTHER THAN AN INSTANTANEOUS
> FIELD,
> ! ASSUME ID(18-20), ARE PASSED IN CORRECTLY.
>
> IF(IFMIN .GE. 1)THEN
> ! ID(17) = 0
> ! COMPUTE THE TOTAL FORECAST MINUTES.
> TOTMIN=IFHR*60+IFMIN
>
> ! CHECK FOR 1/2 HOURLY INCREMENTS.
> IF (MOD(TOTMIN, 30) == 0) THEN
> ID(17) = 14
> DIV = 30
> ! CHECK FOR 1/4 HOURLY INCREMENTS.
> ELSEIF (MOD(TOTMIN, 15) == 0) THEN
> ID(17) = 13
> DIV = 15
> ! OTHERWISE, USE MINUTES.
> ELSE
> ID(17) = 0
> DIV = 1
> ENDIF
>
>
> Does this look OK to you?
>
> Thx
> Ivan
>
>
>
>
>
> On 11/15/2017 02:39 PM, Wesley Ebisuzaki - NOAA Federal wrote:
>
> Ivan,
>
> I am not aware of a time unit 14. It's not in NCEP's documentation.
>
> Wesley
>
> http://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_table4-4.shtml
>
> On Wed, Nov 15, 2017 at 4:27 AM, Ivan Toman <ivtoman at inet.hr> wrote:
>
>> Wesley,
>>
>> I finally found time to dig into this.
>>
>> I actually get "undefined time unit 14" from wgrib2 when trying to handle
>> 30 min records. That's probably why g2ctl, alt_g2ctl also does not do the
>> job (throwing this message) and so on.
>>
>> For example, your suggestion #2:
>>
>> $ wgrib2 wrfprs_d01.00_30.g2 -if ":30 min fcst:" -set_ftime "30 min fcst"
>> -fi -grib wrfprs_d01.00_30.g2.con
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> 1:0:d=2017111500 <%28201%29%20711-1500>:RWMR:1 hybrid level:1 ? fcst:
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> 2:2310:d=2017111500 <%28201%29%20711-1500>:SNMR:1 hybrid level:1 ? fcst:
>> add_time: undefined time unit 14
>> ...
>>
>>
>> Or...
>>
>> $ alt_gmp -i wrfprs_d01.grib2.ctl
>> wgrib2_flags=-npts -set_ext_name 1 -end_FT -ext_name -lev
>> wgrib2_inv=.invd01
>> dtype: dtype grib2
>> pdef: pdef 149 149 lccr -29.363000 45.203000 1 1 -21.633000 -21.633000
>> 54.288000 12000.000000 12000.000000tdef: nt=7 start=00Z15nov2017 by=10mn
>> zdef: nlevel=25
>> resolve_dsets dset=wrfprs_d01.grib2 inctime=10mn
>> resolve_dsets: no template
>> scanning wrfprs_d01.grib2 (process=0)
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>> add_time: undefined time unit 14
>>
>>
>>
>> grib1to2.pl did not work either, it failed:
>>
>> $ for i in WRFPRS_d01.0* ; do ./grb1to2.pl -o $i.g2 $i ; done
>> (((rec 1:0:date 2017111500 <%28201%29%20711-1500> RWMR kpds5=170
>> kpds6=109 kpds7=1 levels=(0,1) grid=255 hybrid lev 1 anl:
>> RWMR=Rain water mixing ratio [kg/kg]
>> timerange 0 P1 0 P2 0 TimeU 1 nx 149 ny 149 GDS grid 3 num_in_ave 0
>> missing 0
>> center 7 subcenter 0 process 125 Table 2 scan: WE:SN winds(grid)
>> Lambert Conf: Lat1 -29.363000 Lon1 45.203000 Lov 54.288000
>> Latin1 -21.633000 Latin2 -21.633000 LatSP -90.000000 LonSP 0.000000
>> South Pole (149 x 149) Dx 12.000000 Dy 12.000000 scan 64 mode 136
>> min/max data 0 0 num bits 0 BDS_Ref 0 DecScale 0 BinScale 0
>>
>> )))
>> >> grib2_metadata --- WRFPRS_d01.00_00 wgrib=./wgrib wgrib2=./wgrib2
>> Use of uninitialized value $1 in negation (-) at ./grib1to2_metadata.pl
>> line 74, <INV> line 1.
>> no scan mode at ./grib1to2_metadata.pl line 83, <INV> line 1.
>> missing GRIB record(s)
>> ((()))
>> Problem, winds not defined! old ./wgrib?
>> grib2 message ignored (use wgrib2)
>> missing GRIB record(s)
>> ((()))
>> Problem, winds not defined! old ./wgrib?
>> (((rec 1:0:date 2017111500 <%28201%29%20711-1500> RWMR kpds5=170
>> kpds6=109 kpds7=1 levels=(0,1) grid=255 hybrid lev 1 10min fcst:
>> RWMR=Rain water mixing ratio [kg/kg]
>> timerange 10 P1 0 P2 10 TimeU 0 nx 149 ny 149 GDS grid 3 num_in_ave 0
>> missing 0
>> center 7 subcenter 0 process 125 Table 2 scan: WE:SN winds(grid)
>> Lambert Conf: Lat1 -29.363000 Lon1 45.203000 Lov 54.288000
>> Latin1 -21.633000 Latin2 -21.633000 LatSP -90.000000 LonSP 0.000000
>> South Pole (149 x 149) Dx 12.000000 Dy 12.000000 scan 64 mode 136
>> min/max data 0 5.31824e-06 num bits 16 BDS_Ref 0 DecScale 11
>> BinScale 4
>>
>>
>>
>> I have no idea how to proceed further.
>> Tks,
>> Ivan
>>
>>
>>
>>
>> On 11/07/2017 08:12 PM, Wesley Ebisuzaki - NOAA Federal wrote:
>>
>> Ivan,
>>
>> "UPP follows NCEP code table for timing grib records - for 15 and 30
>> minute records use codes 13 and 14 respectively instead of simple
>> minutes. This seems to confuse GrADS (or g2ctl/gribmap, I'm not sure)."
>>
>> "Yes it is fixed. I'm currently need to output 10 min intervals. So, for
>> full hour, 10m, 20m, 40m and 50m I get OK data. But for 30m I do not."
>>
>> These quotes suggests that it is a problem with gribmap expecting
>> 30 minute_time_units and not being able to handle 1 30_minute_time_units.
>>
>> Suggestion #1
>>
>> use alt_g2ctl/alt_gmp
>>
>> Both are based on wgrib2 which uses english rather than code table
>> numbers.
>>
>> Suggestion #2
>>
>> convert forecast time from 1 (30 minutes) to 30 (minutes)
>>
>> wgrib2 IN.grb -if ":30 min fcst:" -set_ftime "30 min fcst" -fi -grib
>> OUT.grb
>>
>> Wesley
>>
>>
>>
>>
>>
>>
>> On Tue, Nov 7, 2017 at 1:21 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> What result do you get when you do
>>>
>>> wgrib2 -T (grib file)
>>>
>>> ?
>>>
>>> Look after the "D=", as the represents the time in the GRIB2 file.
>>>
>>> Jeff
>>>
>>> On Tue, Nov 7, 2017 at 12:10 PM, Ivan Toman <ivtoman at inet.hr> wrote:
>>>
>>>> Hello,
>>>>
>>>> Yes it is fixed. I'm currently need to output 10 min intervals. So, for
>>>> full hour, 10m, 20m, 40m and 50m I get OK data. But for 30m I do not.
>>>>
>>>> Thank you!
>>>> Ivan
>>>>
>>>>
>>>>
>>>>
>>>> On 11/07/2017 05:50 PM, Jeff Duda wrote:
>>>>
>>>> What is your time interval? If it's not fixed, that's one problem. If
>>>> it is fixed, then I don't see why regular templating wouldn't work unless
>>>> the time being written to the grib2 file is not right. But there are ways
>>>> to fix that.
>>>>
>>>> Jeff Duda
>>>>
>>>> On Tue, Nov 7, 2017 at 10:12 AM, Ivan Toman <ivtoman at inet.hr> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I'm having difficulties reading sub-hourly time records from WRF grib
>>>>> files in GrADS.
>>>>>
>>>>> UPP follows NCEP code table for timing grib records - for 15 and 30
>>>>> minute records use codes 13 and 14 respectively instead of simple
>>>>> minutes. This seems to confuse GrADS (or g2ctl/gribmap, I'm not sure).
>>>>>
>>>>> What I get as result is that I can read any sub-hourly record as long
>>>>> as
>>>>> it is not 15 or 30 minute record. For those, I get undefined grid
>>>>> instead of data.
>>>>>
>>>>> I use this workflow for postprocessing: wfrout >(UPP)> grib1
>>>>> >(cnvgrib)>
>>>>> grib2 >(g2ctl,gribmap)> GrADS
>>>>>
>>>>> Does anybody know what is going on there?
>>>>>
>>>>> Thank you in advance
>>>>>
>>>>> Ivan Toman
>>>>>
>>>>> _______________________________________________
>>>>> gradsusr mailing list
>>>>> gradsusr at gradsusr.org
>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Jeff Duda
>>>> Post-doctoral research fellow
>>>> University of Oklahoma School of Meteorology
>>>>
>>>>
>>>> _______________________________________________
>>>> gradsusr mailing listgradsusr at gradsusr.orghttp://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>>
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>>>>
>>>>
>>>
>>>
>>> --
>>> Jeff Duda
>>> Post-doctoral research fellow
>>> University of Oklahoma School of Meteorology
>>>
>>> _______________________________________________
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>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
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