Re: [idvusers] Time in GRIB2 files from CFSR

On Tue, 9 Mar 2010, Robb Kambic wrote:

> On Tue, 9 Mar 2010, Guilherme Chagas wrote:
>
> > Hello folks!
> >
> > I have some GRIB2 files from the Climate Forecast System Reanalysis,
> > downloaded from the NCAR database (monthly means of analysis for U and
> > V @ 1000mb), which open up just fine, but strangely enough there's a
> > shift of several months in the time displayed in IDV. Instead of
> > starting at 1979-01-01 the first time listed is 1977-11-10,
> > consequently ending earlier than expected. A quick look using wgrib2
> > shows valid records starting from 1979-01-01 until 2009-09-01!

Guilherme,

I fixed the Time problem but I was comparing the results with wgrib2. It 
seems that wgrib2 calculates the forecast time differently then our grib 
library. Our library figures out the valid time that is the end of the 
accumulation interval verses the wgrib2 that uses the start of the 
interval.

hours since 1979-01-01T00:00:00Z
time = 124, 856, 1540, 2280, 3004, 3744, ....
 1979-01-06 04:00:00Z
 1979-02-05 16:00:00Z
 1979-03-06 04:00:00Z
 1979-04-06 00:00:00Z
 ...


wgrib2:

1.1:0:d=1979010100
2.1:149612:d=1979020100

Does this make sense?

Robb...

> Hi Guilherme,
>
> A sample file was downloaded from NCAR for a test. The Time problem is in the 
> underlining Grib library that the IDV uses. A fix will be made and passed 
> onto the IDV developers. I don't know the time frame when you will get the 
> fix, but the fix will be implemented in the next days.
>
> Robb...
>
>
>
>
> > The IDV version used was 2.8u1 (Windows 7 32bits) and 2.7u2 (Linux
> > i686), both displayed the same issue.
> >
> > Has someone else experienced similar issues with other GRIB2 files, or
> > properly loaded CFSR monthly means?
> >
> > Thanks!
> > ___________________________
> >                Guilherme O. Chagas
> >                               address@hidden
> >
> > _______________________________________________
> > idvusers mailing list
> > address@hidden
> > For list information, to unsubscribe, visit: 
> > http://www.unidata.ucar.edu/mailing_lists/
>
> ===============================================================================
> Robb Kambic                                Unidata Program Center
> Software Engineer III			   Univ. Corp for Atmospheric 
> Research
> address@hidden             WWW: http://www.unidata.ucar.edu/
> ===============================================================================

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================