On Tue, Oct 4, 2011 at 6:50 AM, Molin Antoine <span dir="ltr"><<a href="mailto:antoine.molin@poweo.com">antoine.molin@poweo.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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Hi,<br>
<br>
Thanks for your answer.<br>
<br>
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°. <br>
<br></div></blockquote><div><br></div><div>For the record, this should not make a difference. Here is the lats4d syntax to bring about a week of data with these:</div><div><br></div><div>% lats4d.sh -i <a href="http://goldsmr2.sci.gsfc.nasa.gov:80/dods/MAT1NXSLV">http://goldsmr2.sci.gsfc.nasa.gov:80/dods/MAT1NXSLV</a> -vars slp u50m v50m t2m -time 0:30z01jan2001 23:30z07jan2001 -o merra_slv -v</div>
<div><br></div><div>(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 "<a href="http://merra_slv.nc">merra_slv.nc</a>"; use the -format option to choose another format.</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div text="#000000" bgcolor="#ffffff">
So i downloaded the Merra data, hdf files, with the variables SLP,
U50m, V50m and T2m.<br><br></div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div text="#000000" bgcolor="#ffffff">
* the variable SLP is not recognized by Grads! </div></blockquote><div><br></div><div>The attached file does not have SLP. Please file a bug report with the M-DISC.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div text="#000000" bgcolor="#ffffff">(the variable "SLP"
is on the Merra site:
<a href="http://disc.sci.gsfc.nasa.gov/daac-bin/FTPSubset.pl?LOOKUPID_List=MAT1NXSLV" target="_blank">http://disc.sci.gsfc.nasa.gov/daac-bin/FTPSubset.pl?LOOKUPID_List=MAT1NXSLV</a>)<br>
<br>
* 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?<br>
<br></div></blockquote><div><br></div><div>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):</div><div>
<br></div><div><div>dset ^MERRA.%y4%m2%d2.SUB.hdf</div><div>options template </div><div>tdef <span class="Apple-style-span" style="background-color: rgb(255, 255, 0);">time</span> 24 linear <span class="Apple-style-span" style="background-color: rgb(255, 255, 0);">00:30</span>Z01jan2001 1hr</div>
</div><div><br></div><div>If you need a relatively short period of time, why mess with this? Just use lats4d as above and save yourself some work.</div><div><br></div><div> Arlindo</div><div><br></div><div><br></div><div>
<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div text="#000000" bgcolor="#ffffff">
Thanks, and best regards.<br>
Antoine Molin<br>
<br>
<br>
<br>
<br>
<br>
Le 30/09/2011 22:17, Arlindo da Silva a écrit :
<div><div></div><div class="h5"><blockquote type="cite">On Fri, Sep 30, 2011 at 4:22 AM, Molin Antoine <span dir="ltr"><<a href="mailto:antoine.molin@poweo.com" target="_blank">antoine.molin@poweo.com</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
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<div>Dear All,<br>
<br>
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 <a>file:hourly</a> wind
speeds at 50m for one day, NetCDF).<br>
But then?<br>
Could you tell me how you would:<br>
* aggregate the daily files: do you use "template"<br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>Yes.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
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<div> * 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?).<br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>Using a template makes it easier to work with the HDF
files.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
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<div> * best way to eventually create the descriptor file<br>
</div>
</div>
</blockquote>
<div><br>
</div>
<div>Yes, it should be sufficient to create a DDF file with 3
records: DSET, OPTIONS template, and TDEF. Please read the
User's Guide:</div>
<div><br>
</div>
<div> <a href="http://grads.iges.org/grads/gadoc/SDFdescriptorfile.html" target="_blank">http://grads.iges.org/grads/gadoc/SDFdescriptorfile.html</a></div>
<div><br>
</div>
<div>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: <a href="http://cookbooks.opengrads.org/index.php?title=Table_of_Contents#NASA.2FGSFC_MERRA" target="_blank">2.6.1
NASA/GSFC MERRA</a></div>
<div><br>
</div>
<div>The opengrads bundle also ships with a GUI interface for
browsing the MERRA datasets, see</div>
<div><br>
</div>
<div> <a href="http://cookbooks.opengrads.org/index.php?title=Recipe-016:_Accessing_MERRA_data_with_a_Graphical_User_Interface" target="_blank">http://cookbooks.opengrads.org/index.php?title=Recipe-016:_Accessing_MERRA_data_with_a_Graphical_User_Interface</a></div>
<div><br>
</div>
<div>Just type "merra" on the command line; under Windows you
should have a MERRA icon on your desktop.</div>
<div><br>
</div>
<div> Arlindo</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>
<br>
</div>
<div><br>
</div>
</div>
-- <br>
Arlindo da Silva<br>
<a href="mailto:dasilva@alum.mit.edu" target="_blank">dasilva@alum.mit.edu</a><br>
</blockquote>
<br>
<br>
</div></div><div>-- <br><div class="im">
<br>
<div>-- <br>
<div>
<p class="MsoNormal"><b><span style="font-size:10pt;color:rgb(88, 89, 91)">Antoine
Molin</span></b></p>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Arlindo da Silva<br><a href="mailto:dasilva@alum.mit.edu">dasilva@alum.mit.edu</a><br>