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Frequently Asked Questions

Here you will find some frequently asked questions. If your question was not addressed here or anywhere else on our website, then please ask for help in our web forum (http://forum.hycom.org) or search our wiki (http://wiki.hycom.org).



What is the difference in the GLBy/GLBv/GLBu grids? Print

GLBy0.08 grid is 0.08 deg lon x 0.04 deg lat that covers 80 S to 90 N.

GLBv0.08 grid is 0.08 deg lon x 0.08 deg lat between 40S - 40 N. Poleward of 40 S / 40 N, the grid is 0.08 deg lon x 0.04 deg lat. It spans 80 S to 90 N.

GLBu0.08 grid is 0.08 deg lon x 0.08 deg lat that covers 80 S to 80 N.

NOTES:

  • (2018-Dec-08): GLBu grid outputs have been turned off.
  • (2018-Dec-13): GOFS 3.1 currently makes both GLBv and GLBy files, with the intent that GLBv will be turned off once FNMOC makes sure all downstream products can deal with GLBy grid files.

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    Did you know there are missing days in the GOFS 3.1 Global Reanalysis? Print

    Yes. We are aware that some days in the GOFS 3.1 Global Reanalysis (GLBv0.08/expt_53.X) are missing data. We will not be filling in these data gaps. There are times when the daily Global Ocean Forecast System does not run due to computer issues, problematic input data sources, or other unforeseen problems. The following times are known to be missing from the Global Reanalysis.

    Read more...
     
    What are the major differences between GOFS 3.1 and GOFS 3.0? Print

    Global Ocean Forecasting System (GOFS)

    GOFS 3.1 GOFS 3.0
    HYCOM source code 2.2.99DHMTi 2.2.19
    Equation of state 17-term 7-term
    Layers 41, nine additional layers near the surface, top 14 layers are always sigma-z so that water shallower than 84 m is always in fixed coordinates 32
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    Did you know there are days in GLBu0.08 Analysis missing data? Print
    Yes. We are aware that some days in the GLBu0.08/expt_9x.x experiments are missing NetCDF data. Without interpolation, there is no way for us to fill in these data gaps. There are times when the daily Global Ocean Forecast System does not run due to computer issues, problematic input data sources, or other unforeseen problems. The following times/days are known to be missing from GLBu0.08/expt_91.1 (see GLBu0.08 Documentation here):

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    Did you know there are missing days in the GOFS 3.0 Global Reanalysis? Print

    Yes. We are aware that some days in the Global Reanalysis (GLBu0.08/expt_19.x) are missing data. We will not be filling in these data gaps. There are times when the daily Global Ocean Forecast System does not run due to computer issues, problematic input data sources, or other unforeseen problems. The following times are known to be missing from the Global Reanalysis.

    Read more...
     
    Where can I find the pretty pictures and animations of HYCOM data? Print

    NRL creates GIF movies and snapshots for the following HYCOM model runs:

     
    What causes a change in experiment number? Print

    New experiment numbers correspond to improvements in either the code or data assimilation.

     
    Explain the hycom grid? Print

    The global hycom grid is rectilinear from j=1 to j=2172, and you can check this by confirming that the minval and maxval of plat(1:4500,j) are identical there. The grid is curvilinear (bi-polar patch) from j=2173 to j=3298. Note that the j=3298 row is a permuted copy of j=3297 (because of the way the tripole grid is implemented in HYCOM), so you can discard j=3298.

     
    Did you know there are days missing data? Print
    Yes. We are aware that some days (early on in the GLBa0.08 model runs) are missing data. Without interpolation there is no way for us to fill in these data gaps. There are times when the daily Global Ocean Forecast System does not run due to computer issues, problematic input data sources, or other unforeseen problems. The following days are known to be missing data from the GLBa0.08 model, spanning multiple experiments (see GLBa0.08 Documentation here):

    Read more...
     
    How much storage is required for the HYCOM data in netCDF format? Print

    Here is the breakdown of the GLBa0.08 data files for a 00Z snapshot (1 day):

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    How much CPU time is required to produce the HYCOM GLBa0.08 data? Print
    Currently running on a Cray XT5 (at the Navy DSRC), the HYCOM GLBa0.08 with data assimilation takes about 2 wall hours per model day using 624 cores (78 nodes, each holding two AMD Barcellona 4-core chips).

     
    Can I rely on data to be updated on a daily basis? Print
    No. This is a demonstration product from the HYCOM Consortium and is provided as is. HYCOM Consortium does not warrant or suggest that this data is fit for any particular purpose. Further, neither COAPS nor HYCOM consortium guarantee availability, service updates or timely data delivery.

     
    How can I access the latest Gulf of Mexico forecasts? Print
    Go to the GoM (GOMl0.04) model information page.

     
    How can I access the latest Global ocean forecasts? Print
    Go to the Global (GLBa0.08) model information page.

     
    How do I request a HYCOM account? Print

    Click Account Request in the left-hand menu, or click here.