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Re: [Fwd: [Fwd: Forecast Model Run Collection Aggregation prototype available]]

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  • Subject: Re: [Fwd: [Fwd: Forecast Model Run Collection Aggregation prototype available]]
  • Date: Wed, 16 Aug 2006 11:10:16 -0400
This will be a challenge for sure.
The NARR, for example, will be an aggregation of ~75000 grib files.
Stored in a basic ./YYYYMM/YYYYMMDD tree.  The recursive datasetScan
tag added recently helps a ton with this.  Some of our datasets have
forecast hours, some don't.  Doing n forecast hour aggregation across
the 00hr will help termendously with all of them, however.
While it works wonderfully for NetCDF, I cannot see the NcML agg.
working with this set of data ~
mainly due to the changing reference times.

According to NCEP, our NAM & GFS will soon be foreced into GRIB2.
But NCDC-NOMADS NWP it currently entirely a GRIB-1 archive.
Only recently home-grown NCDC datasets are created in NetCDF.

For NAM & GFS, we have about 6 months online, which comes out to
about 700 file when stripped to a 1 forecast time
(say 00hr) aggregation.  But there are 61 forecast times for GFS, and 21
for NAM.

-Dan
>>
>>
>> Especially for GRIB files, you likely need this new "Forecast Model
>> Run Collection Aggregation" capability. We have been working with our
>> IDD NCEP GRIB files, and there are some complications, especially
>> non-homogenaity due to missing records and variable time and vertical
>> dimensions, that cant really be solved by the current (index based)
>> aggregation.
>> Ethan and I will work closely with you guys to get this working. I'd
>> like to understand what you have in more detail, number and types of
>> files, how they are stored, etc. Can you or someone summarize?
>>
>> John
> 
> 
> 

-- 
Dan Swank <address@hidden>
NOMADS Project:  Software & Data Management
Contractor - STG, Incorporated
Veach-Baley Federal Building
151 Patton Avenue
Asheville, NC 28801-5001
Phone: 828-271-4007