[Met_help] Points of clarification for data conversion/usage in MODE

John Halley Gotway johnhg at ucar.edu
Fri Mar 12 11:01:46 MST 2010


Creating a GRIB file is a rather ambitious task I have never actually done myself.  If I were in your position, I'd actually reformat your binary data into a NetCDF file that looks like the output of
the PCP-Combine tool.  MODE can read either GRIB data or the NetCDF output of PCP-Combine.  There are a lot more utilities out there for writing NetCDF files than there are for writing GRIB files.

Use the "ncdump" utility to view the NetCDF output from PCP-Combine in the "METv2.0/out/pcp_combine" directory.  These files are created when you run the test script included with MET.  And just
mimick the file structure with your data.

If you choose to go that route, you'll probably need some help choosing the variable name and setting up the grid definition information in NetCDF header.  We're working on expanding our support for
NetCDF files for the next release of MET.  They're a lot easier to work with than GRIB files are.

Let me know how you plan to proceed and what other questions you have.


Matthew Souders wrote:
> Hello John,
> This is Matthew Souders (Stony Brook University) - I apologize for taking up
> a bit more of your time, but I am running into some trouble getting data
> read into MODE for which I thought you might have a solution on hand to
> help.  My basic data is a single variable on a 2.5 by 2.5 degree regular
> lat/lon grid in fortran direct access BINARY format.  I have been trying to
> get it intelligibly read into GRIB format (the form MODE needs) for a month
> now using Wesley Ebusizaki's gribw utility; however, you need a rather
> significant background in C scripting to rewrite his basic code and make
> proper use of the PDS file writer.  As I understand it...MODE needs this PDS
> file to operate properly.  I can create a GRIB using the default PDS file,
> but that doesn't accurately describe the data in the GRIB.
> I tried e-mail Wesley on this matter but he is understandably extremely busy
> and limits support to installation and debugging issues.  He basically just
> directed me to the GRIB standard release.  I was wondering if you had any
> experience getting binary data read into MODE or if you knew someone who
> might be able to help?
> I also would like to know how exactly the MODE tool uses the PDS file?  I
> ask because I am trying to figure out how picky it is w/r/t what is in the
> PDS file vs. what is in the actual GRIB file.
> Thanks in advance for your time.
> Matt Souders.

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