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 FAQs > Using Data
- What is in the MSS files?
The content is described on the dataset home page and is often qualified in the MSS file list. The data is in one of these general forms: packed binary, packed ASCII, or flat ASCII. You can usually find the format by clicking the  tab on the dataset home page. For formats that are common to one or more datasets, such as GRIB1, BUFR or NMC Office Note 29, see the Software/Documentation section of our website. For assistance with the content of data files, please contact the dataset specialist (CONTACT: on the dataset home page), or email DataHelp.
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- What is COS-blocking and how do I deal with it?
COS-blocking is a legacy blocking scheme that was used on NCAR's Cray computers. While the Crays no longer exist, many of our datasets still have files which use COS-blocking. Software for handling COS-blocked files may be found here.
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- How do I read the contents of a data file?
For binary or packed-ASCII files, we usually provide access software which may be found by clicking the  tab on the dataset home page. A file with a flat ASCII format is human-readable and often can be imported into a spreadsheet, so there may not be software available to deal with it. For software to deal with common data formats, see the Software/Documentation section of our website. For assistance with reading data files, please contact the dataset specialist (CONTACT: on the dataset home page), or email DataHelp.
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- What are the GBYTES calls in your software?
GBYTES code is used by many DSS programs to handle binary packing. All the details are here. For further assistance with using GBYTES, please email DataHelp.
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- How do I get a subset of the data?
To see if this is possible, contact the dataset specialist (CONTACT: on the dataset home page), or email DataHelp.
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- Why can't I find certain days, times or fields of data I expected on a data file?
See these processing tips. It is also
possible that the data just isn't available. Check the inventory
to verify its presence. On the relevant dataset's main page, click on
the  tab. GRIB data users
may use the WGRIB software to check the file.
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- Why are some of observations missing from the NCEP ADP data files?
There are several possibilities. First, keep in mind that this data was
collected on an operational basis by NCEP from the Global Telecommunications
Sustem (GTS). This means that when a station doesn't send its data report
over to the GTS, it won't be available for the ADP data files. When a station
fails to send the report before the cutoff time for making the FNL analyses,
it won't be collected for the ADP data files. When this happens, the report
might be collected at a climate center, but it would not be put into the
format used in the ADP data files. Often a station simply did not make an
observation. This can happen due to any of a number of reasons, such as
economic, war, severe site conditions, equipment failure. We do not attempt
to recover missing reports because the task is simply too big for us. For
a complete description of NCEP's collection process, see
Observational Data Processing at NCEP.
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- Why won't the MM5 (or RAMS) read the data file?
Usually this is due to using a file which does not have a recognizable
structure. The atmospheric data content is probably OK, but some sort
of filter is often needed to add or remove a "system envelope." It may
also be that the dataset is not one of those that can be used. See
MM5 help and
RAMS help.
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- Where can I find information about using data on my computer?
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- Who can use the ECMWF datasets?
ECMWF allows us to redistribute their data to users at U.S. universities. Those to whom we can provide the data must sign a permission form wherein they agree to ECMWF's restrictions. Each of our affected ECMWF dataset home pages has a link to the appropriate form for that dataset.
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