[gradsusr] use GRACE satallite data in GrADS

[Jennifer M Adams]

Hi, Bimal —
Well, I guess is it considerate of the GRACE data providers to tell you which months are missing, but it makes their data file unusable by GrADS in its current form. GrADS requires a linear time axis — the increment between each time step must be the same — and it looks like this file does not conform to that standard. It would have been better if they had simply padded their file with missing data for those months, but file size constraints can sometimes trump usability requirements.

Your options are to use another tool that explicitly reads the time metadata for each time step and doesn’t care if the increments are different, or to break up your file into pieces (say one file per month) that can be aggregated together in a virtual way using templating (http://cola.gmu.edu/grads/gadoc/templates.html). GrADS will handle the missing months if you do it this way (one file per month, and some files missing), but it may be a bit of a chore to slice up your original file. The NetCDF operators (http://nco.sourceforge.net/) are pretty good at that job.
—Jennifer


On Jul 8, 2016, at 9:37 AM, Bimal Gyawali <bml.gya at gmail.com<mailto:bml.gya at gmail.com>> wrote:

Hi All,
I would like analyze GRACE netcdf data using GrADS. when I do ncdump I found the following information. I am new to grads and I dont know how to handle with those kind of datasets. when I plotted time series the plot is only up to 2012. I dont know how to convert the time and skip those missing months.  Please can anyone help me with how to work with this data?
 time:units = "days since 2002-01-01 00:00:00"
  time_epoch = "2002-01-01 00:00:00" ;
  time_start = " 107.5 days since epoch or 2002-04-18" ;
  time_end = "5104.5 days since epoch or 2015-12-23" ;
  months_missing = "2002-06;2002-07;2003-06;2011-01;2011-06;2012-05;2012-10;2013-03;2013-08;2013-09;2014-02;2014-12,2015-06" ;
Thank you.

Bimal Gyawali
Graduate Research Assistant
Department of Physical and Environment Science
Natural Resources Center
Texas A&M University-Corpus Christi
Corpus Christi, TX 78412
Tel: 435-881-3603

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--
Jennifer Miletta Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
George Mason University



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