[gradsusr] GFS total cloud cover

Thu Nov 3 14:08:03 EDT 2016

Sam,

   Which version of wgrib2?  (wgrib2 -config)

   Try increasing the stack size.  (bash: ulimit)

Wesley

On Thu, Nov 3, 2016 at 1:32 PM, Sam Wilson <sam at surfline.com> wrote:

> Moorthi and Wesley,
>
> Thanks very much for the feedback - I attempted using the ncep_norm option
> with wgrib2, but got a segmentation fault..argh!
>
> My software installation skills are sub-par, so I will try Moorthi’s
> option and get back to the group.
>
> Thanks again..
>
> Cheers,
> Sam
>
> From: <gradsusr-bounces at gradsusr.org> on behalf of Wesley Ebisuzaki -
> NOAA Federal <wesley.ebisuzaki at noaa.gov>
> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
> Date: Thursday, November 3, 2016 at 5:59 AM
> To: GrADS Users Forum <gradsusr at gradsusr.org>
> Subject: Re: [gradsusr] GFS total cloud cover
>
> Sam,
>
>   You can get the "0-1 hour ave fcst", "1-2 hour ave fcst", etc
> by using the -ncep_norm option of wgrib2.
>
>    http://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/ncep_norm.html
>
> Here is a simple script that takes a list of gfs forecast files in order
>
>
> #!/bin/sh
> #
> # usage $0 (list of gfs grib2 forecast files in order)
> #
> A=":TCDC:entire atmosphere:"
> B=":TCDC:low cloud layer:"
> C=":TCDC:middle cloud layer:"
> D=":TCDC:high cloud layer:"
>
> cat $* | wgrib2 - -match "($A|$B|$C|$D)" -set_grib_type c3 \
>    -if "$A" -ncep_norm $stmp/junk \
>    -if "$B" -ncep_norm $stmp/junk \
>    -if "$C" -ncep_norm $stmp/junk \
>    -if "$D" -ncep_norm $stmp/junk
>
>
> Wesley
>
>
> On Thu, Nov 3, 2016 at 6:59 AM, Shrinivas Moorthi <
> shrinivas.moorthi at noaa.gov> wrote:
>
>> The grib header is correct.
>> Let us denote the data from 6 hourly output as C1, C2, C3, C4, C5, C6.
>>
>> To get hourly mean, then
>> for hour 1, the mean is C1,
>> for hour 2, the mean is 2C2-C1
>> for hour 3, the mean is 3C3-2C2
>> for hour 4, the mean is 4C4-3C2
>> for hour 5, the mean is 5C5-4C4
>> and for hour 6, it is 6C6-5C5
>>
>> This pattern repeats every six ours.
>> I hope this helps.
>> Moorthi
>> On 11/02/2016 07:41 PM, Sam Wilson wrote:
>>
>> Hi Jeff,
>>
>> I plotted a quick and dirty cloud animation using the data - each step is
>> 1 hour from f001 through f015 in the attached.
>>
>> It appears that they are averages over time - you can see the bigger
>> jumps at steps 8 and 14 (the transition from 0-6hr avg to 6-7hr and from
>> 6-12hr avg to 12-13hr).
>>
>> Marian - thank you for the feedback.  Sounds like using the hourly data
>> for cloud cover may not be a good idea, unless someone else has a solution.
>>
>> Thanks,
>> Sam
>>
>> From: <gradsusr-bounces at gradsusr.org> on behalf of Jeff Duda <
>> jeffduda319 at gmail.com>
>> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
>> Date: Wednesday, November 2, 2016 at 3:21 PM
>> To: GrADS Users Forum <gradsusr at gradsusr.org>
>> Subject: Re: [gradsusr] GFS total cloud cover
>>
>> Sam,
>> That might just be a wgrib table thing. Have you actually plotted the
>> field over those times? If it's truly an averaged field, you should be able
>> to see some indication of that in the texture and smoothness of the fields
>> as you progress through increasing averaged times.
>>
>> My guess is that this is just some arbitrary setting in wgrib and does
>> not reflect the true nature of the field. But I could be wrong. If there
>> are any NCEP folks who work on the GFS on this forum, perhaps one of them
>> could set the record straight.
>>
>> Jeff
>>
>> On Wed, Nov 2, 2016 at 4:54 PM, Sam Wilson <sam at surfline.com> wrote:
>>
>>> Thanks for the response Jeff - it’s strange to me as well!
>>>
>>> Running wgrib2 on the data files for forecast hours 001 through 007
>>> gives the following for TCDCclm:
>>>
>>> *f001:*
>>> 17:7991683:d=2016110212:TCDC:entire atmosphere:*0-1* hour ave fcst:
>>> *f002:*
>>> 17:8082626:d=2016110212:TCDC:entire atmosphere:*0-2* hour ave fcst:
>>> *f003:*
>>> 17:8059826:d=2016110212:TCDC:entire atmosphere:*0-3 *hour ave fcst:
>>> *f004:*
>>> 17:8057865:d=2016110212:TCDC:entire atmosphere:*0-4* hour ave fcst:
>>> *f005:*
>>> 17:8119289:d=2016110212:TCDC:entire atmosphere:*0-5* hour ave fcst:
>>> *f006:*
>>> 17:8172510:d=2016110212:TCDC:entire atmosphere:*0-6* hour ave fcst:
>>> *f007:*
>>> 17:8013825:d=2016110212:TCDC:entire atmosphere:*6-7* hour ave fcst:
>>>
>>> And it continues on..once the files go to 3 hourly (after hour 120), we
>>> have:
>>>
>>> *f123:*
>>> 17:7687687:d=2016110212:TCDC:entire atmosphere:*120-123* hour ave fcst:
>>> *f126:*
>>> 17:7778871:d=2016110212:TCDC:entire atmosphere:*120-126* hour ave fcst:
>>> *f129:*
>>> 17:7728042:d=2016110212:TCDC:entire atmosphere:*126-129* hour ave fcst:
>>>
>>> And finally the 12 hourly files (past hour 240) are all just 12 hour
>>> average forecasts:
>>>
>>> *f252:*
>>> 17:6845416:d=2016110212:TCDC:entire atmosphere:*240-252* hour ave fcst:
>>>
>>> I did think about the method you suggested (tcdcclm - tcdcclm(t-1)) but
>>> stopped there for the reason you mentioned..
>>>
>>> Strange indeed - unless I’m missing something..
>>>
>>> Thanks,
>>> Sam
>>>
>>> From: <gradsusr-bounces at gradsusr.org> on behalf of Jeff Duda <
>>> jeffduda319 at gmail.com>
>>> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
>>> Date: Wednesday, November 2, 2016 at 2:08 PM
>>> To: GrADS Users Forum <gradsusr at gradsusr.org>
>>> Subject: Re: [gradsusr] GFS total cloud cover
>>>
>>> It seems a little strange to me that the total cloud cover product would
>>> be averaged over time. Is that really the case?
>>>
>>> Anyway, if you really do have an average over overlapping and increasing
>>> windows, with nothing else to go on and without applying the equations of
>>> motion in reverse, you'd have to assume a linear averaging, so subtraction
>>> of subsequent slices of the field (i.e., tcdcclm - tcdcclm(t-1)) would give
>>> you piecewise temporal averages. However, that method would give you
>>> negative cloud cover values which is clearly nonsensical, which again is
>>> why I question whether or not that array contains a temporal average. That
>>> just doesn't make a lot of sense.
>>>
>>> Jeff Duda
>>>
>>> On Wed, Nov 2, 2016 at 3:27 PM, Sam Wilson <sam at surfline.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I’m working with hourly GFS total cloud cover (TCDCclm) and I’m a bit
>>>> stumped on the following..
>>>>
>>>> Given TCDCclm for hours 0-1, 0-2, 0-3, 0-4, 0-5, and 0-6, what is the
>>>> proper way to determine TCDCclm for hours 1-2, 2-3, 3-4, 4-5, and 5-6?
>>>>
>>>> I may be making the problem more difficult than it is..but wanted to
>>>> ping this group to be sure.
>>>>
>>>> Is there an existing grads script that handles this already and if not,
>>>> does anyone here have any insight?
>>>>
>>>> Thanks so much for your time.
>>>>
>>>> Best,
>>>> Sam
>>>>
>>>> _______________________________________________
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>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>
>>>
>>> --
>>> Jeff Duda
>>> Post-doctoral research associate
>>> University of Oklahoma School of Meteorology
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> Jeff Duda
>> Post-doctoral research associate
>> University of Oklahoma School of Meteorology
>>
>>
>> _______________________________________________
>> gradsusr mailing listgradsusr at gradsusr.orghttp://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>>
>> --
>> Dr. Shrinivas Moorthi
>> Research Meteorologist
>> Global Climate and Weather Modeling Branch
>> Environmental Modeling Center / National Centers for Environmental Prediction
>> 5830 University Research Court - (W/NP23), College Park MD 20740 USA
>> Tel:(301)683-3718
>>
>>
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>>
>>
>
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