[gradsusr] merra data

Tue Oct 4 12:47:00 EDT 2011

Hi Antoine,

There was a data ingest problem identified after the original files were
released.  The data were reprocessed and re-released with and increment to
the version number of the file name. The updates mailing list was informed
at the time the data was changed (which is why we recommend users to sign up
for it), but you've acquired the data well after the fact.

I think I've used separately symbolic links and the CHSUB ctl command to get
around that variation in the filename structures.

If you go back in time you'll also find that the different processing
streams have different version numbers. So far, those are the only times the
version characters of the file names change.

Mike

On Tue, Oct 4, 2011 at 12:25 PM, Molin Antoine <antoine.molin at poweo.com>wrote:

> **
> Hi,
>
> Thank you a lot; it is working with Template and xdfopen; for wind energy,
> we are working on ~ 10 years of data.
>
> just a small problem: for 3 months (june to august;, 2010), Merra data have
> another name; that must be another run, i think.
> Best regards.
> Antoine
>
>
>
> Le 04/10/2011 15:49, Arlindo da Silva a écrit :
>
> On Tue, Oct 4, 2011 at 6:50 AM, Molin Antoine <antoine.molin at poweo.com>wrote:
>
>>  Hi,
>>
>> Thanks for your answer.
>>
>> I tasted your cooking, and it is good; but we would like to get the MERRA
>> data at the resolution 2/3 ° x 0.5°.
>>
>>
>  For the record, this should not make a difference. Here is the lats4d
> syntax to bring about a week of data with these:
>
>  % lats4d.sh -i http://goldsmr2.sci.gsfc.nasa.gov:80/dods/MAT1NXSLV -vars
> slp u50m v50m t2m -time 0:30z01jan2001 23:30z07jan2001 -o merra_slv -v
>
>  (Notice that I used lower case "slp".) Go get a cup of coffee and when
> you come back this will create a netcdf file called "merra_slv.nc"; use
> the -format option to choose another format.
>
>
>>  So i downloaded the Merra data, hdf files, with the variables SLP, U50m,
>> V50m and T2m.
>>
>>   * the variable SLP is not recognized by Grads!
>>
>
>  The attached file does not have SLP. Please file a bug report with the
> M-DISC.
>
>
>> (the variable "SLP" is on the Merra site:
>> http://disc.sci.gsfc.nasa.gov/daac-bin/FTPSubset.pl?LOOKUPID_List=MAT1NXSLV
>> )
>>
>> * i tried first to read a hdf file with xdfopen, but the written ddf
>> (enclosed file) is not good; a "SDF_dimension_name" is lacking, i think, for
>> TDEF; but how do you name this dimension_name? and how do you scan a hdf
>> file?
>>
>>
>  Did you create this ctl file or it came with the data? The attached ctl
> is wrong as it mixes elements of DDF and CTL.  Here is a templates DDF (I
> did not try it):
>
>  dset ^MERRA.%y4%m2%d2.SUB.hdf
> options template
> tdef time 24 linear 00:30Z01jan2001 1hr
>
>  If you need a relatively short period of time, why mess with this? Just
> use lats4d as above and save yourself some work.
>
>      Arlindo
>
>
>
>
>
>>  Thanks, and best regards.
>> Antoine Molin
>>
>>
>>
>>
>>
>> Le 30/09/2011 22:17, Arlindo da Silva a écrit :
>>
>> On Fri, Sep 30, 2011 at 4:22 AM, Molin Antoine <antoine.molin at poweo.com>wrote:
>>
>>>
>>> Dear All,
>>>
>>> For wind energy in France, i would like to use Merra data; it is in fact
>>> rather easy to get daily files from the Nasa (enclosed file:hourly wind
>>> speeds at 50m for one day, NetCDF).
>>> But then?
>>> Could you tell me how you would:
>>> * aggregate the daily files: do you use "template"
>>>
>>
>>  Yes.
>>
>>
>>>  * read the aggregate files (i think we need a descriptor file and use
>>> xdfopen or open under grads, isn'it?; or is it better to work with HDF
>>> files?).
>>>
>>
>>  Using a template makes it easier to work with the HDF files.
>>
>>
>>>  * best way to eventually create the descriptor file
>>>
>>
>>  Yes, it should be sufficient to create a DDF file with 3 records: DSET,
>> OPTIONS template, and TDEF. Please read the User's Guide:
>>
>>             http://grads.iges.org/grads/gadoc/SDFdescriptorfile.html
>>
>>  Now, depending on the extent of data analysis you need to perform it may
>> be practical for use to access MERRA data directly through OPeNDAP. In fact,
>> we have made the whole MERRA collection on-line. There are a number of
>> recipes in the Cookbook explaining how to work with MERRA data, click on
>> this link: 2.6.1 NASA/GSFC MERRA<http://cookbooks.opengrads.org/index.php?title=Table_of_Contents#NASA.2FGSFC_MERRA>
>>
>>  The opengrads bundle also ships with a GUI interface for browsing the
>> MERRA datasets, see
>>
>>
>> http://cookbooks.opengrads.org/index.php?title=Recipe-016:_Accessing_MERRA_data_with_a_Graphical_User_Interface
>>
>>  Just type "merra" on the command line; under Windows you should have a
>> MERRA icon on your desktop.
>>
>>      Arlindo
>>
>>
>>
>>
>>
>>  --
>> Arlindo da Silva
>> dasilva at alum.mit.edu
>>
>>
>>
>>  --
>>
>> --
>>
>> *Antoine Molin*
>>
>> **
>>
>> [image: EED POWEO Logo]
>>
>> 16, Place Cormontaigne - 59000 Lille
>>
>> Tel. : *+ 33 3 20 74 04 00*
>>
>> Fax : + 33 3 20 74 04 07 <%2B%2033%203%2020%2074%2004%2007>
>>
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>>
>> **
>>
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>>
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>>
>
>
>  --
> Arlindo da Silva
> dasilva at alum.mit.edu
>
>
>
> --
>
> --
>
> *Antoine Molin*
>
> **
>
> ****
>
> [image: EED POWEO Logo]
>
> 16, Place Cormontaigne - 59000 Lille****
>
> ****
>
> Tel. : *+ 33 3 20 74 04 00*
>
> Fax : + 33 3 20 74 04 07****
>
> *poweo.com <http://www.poweo.com/>*
>
> **
>
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>
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