ncecat(1) [debian man page]
NCECAT(1) General Commands Manual NCECAT(1) NAME
ncecat - netCDF Ensemble Concatenator SYNTAX
ncecat [-3] [-4] [-6] [-A] [-C] [-c] [-D dbg] [-d dim,[ min][,[ max]]] [-F] [-h] [-L dfl_lvl] [-l path] [-M] [-n loop] [-O] [-p path] [-R] [-r] [-t thr_nbr] [-u ulm_nm] [-v var[,...]] [-X box] [-x] input-files output-file DESCRIPTION
ncecat concatenates an arbitrary number of input files into a single output file. Input files are glued together by creating a record dimension in the output file. Input files must be the same size. Each input file is stored consecutively as a single record in the output file. Each variable (except coordinate variables) in each input file becomes one record in the same variable in the output file. Coordi- nate variables are not concatenated, they are instead simply copied from the first input file to the output-file. Thus, the size of the output file is the sum of the sizes of the input files. Consider five realizations, 85a.nc, 85b.nc,... 85e.nc of 1985 predictions from the same climate model. Then ncecat 85?.nc 85_ens.nc glues the individual realizations together into the single file, 85_ens.nc. If an input variable was dimensioned [ lat, lon], it will have dimensions [ record, lat, lon] in the output file. A restriction of ncecat is that the hyperslabs of the processed variables must be the same from file to file. Normally this means all the input files are the same size, and contain data on different realizations of the same variables. EXAMPLES
Consider a model experiment which generated five realizations of one year of data, say 1985. You can imagine that the experimenter slightly perturbs the initial conditions of the problem before generating each new solution. Assume each file contains all twelve months (a seasonal cycle) of data and we want to produce a single file containing all the seasonal cycles. Here the numeric filename suffix denotes the experiment number (not the month): ncecat 85_01.nc 85_02.nc 85_03.nc 85_04.nc 85_05.nc 85.nc ncecat 85_0[1-5].nc 85.nc ncecat -n 5,2,1 85_01.nc 85.nc These three commands produce identical answers. The output file, 85.nc, is five times the size as a single input-file. It contains 60 months of data (which might or might not be stored in the record dimension, depending on the input files). AUTHOR
NCO manual pages written by Charlie Zender and Brian Mays. REPORTING BUGS
Report bugs to <http://sf.net/bugs/?group_id=3331>. COPYRIGHT
Copyright (C) 1995-2010 Charlie Zender This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU- LAR PURPOSE. SEE ALSO
The full documentation for NCO is maintained as a Texinfo manual called the NCO User's Guide. Because NCO is mathematical in nature, the documentation includes TeX-intensive portions not viewable on character-based displays. Hence the only complete and authoritative versions of the NCO User's Guide are the PDF (recommended), DVI, and Postscript versions at <http://nco.sf.net/nco.pdf>, <http://nco.sf.net/nco.dvi>, and <http://nco.sf.net/nco.ps>, respectively. HTML and XML versions are available at <http://nco.sf.net/nco.html> and <http://nco.sf.net/nco.xml>, respectively. If the info and NCO programs are properly installed at your site, the command info nco should give you access to the complete manual, except for the TeX-intensive portions. HOMEPAGE
The NCO homepage at <http://nco.sf.net> contains more information. NCECAT(1)
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NCEA(1) General Commands Manual NCEA(1) NAME
ncea - netCDF Ensemble Averager SYNTAX
ncea [-3] [-4] [-6] [-A] [-C] [-c] [-D dbg] [-d dim,[ min][,[ max]]] [-F] [-h] [-L dfl_lvl] [-l path] [-n loop] [-O] [-p path] [-R] [-r] [-t thr_nbr] [-v var[,...]] [-X box] [-x] [-y op_typ] input-files output-file DESCRIPTION
ncea performs gridpoint averages of variables across an arbitrary number (an ensemble) of input files, with each file receiving an equal weight in the average. Each variable in the output-file will be the same size as the same variable in any one of the in the input-files, and all input-files must be the same size. Whereas ncra only performs averages over the record dimension (e.g., time), and weights each record in the record dimension evenly, ncea averages entire files, and weights each file evenly. All dimensions, including the record dimension, are treated identically and preserved in the output-file. The file is the logical unit of organization for the results of many scientific studies. Often one wishes to generate a file which is the gridpoint average of many separate files. This may be to reduce statistical noise by combining the results of a large number of experi- ments, or it may simply be a step in a procedure whose goal is to compute anomalies from a mean state. In any case, when one desires to generate a file whose properties are the mean of all the input files, then ncea is the operator to use. ncea assumes coordinate variable are properties common to all of the experiments and so does not average them across files. Instead, ncea copies the values of the coordi- nate variables from the first input file to the output file. EXAMPLES
Consider a model experiment which generated five realizations of one year of data, say 1985. You can imagine that the experimenter slightly perturbs the initial conditions of the problem before generating each new solution. Assume each file contains all twelve months (a seasonal cycle) of data and we want to produce a single file containing the ensemble average (mean) seasonal cycle. Here the numeric filename suffix denotes the experiment number (not the month): ncea 85_01.nc 85_02.nc 85_03.nc 85_04.nc 85_05.nc 85.nc ncea 85_0[1-5].nc 85.nc ncea -n 5,2,1 85_01.nc 85.nc These three commands produce identical answers. The output file, 85.nc, is the same size as the inputs files. It contains 12 months of data (which might or might not be stored in the record dimension, depending on the input files), but each value in the output file is the average of the five values in the input files. In the previous example, the user could have obtained the ensemble average values in a particular spatio-temporal region by adding a hyper- slab argument to the command, e.g., ncea -d time,0,2 -d lat,-23.5,23.5 85_??.nc 85.nc In this case the output file would contain only three slices of data in the time dimension. These three slices are the average of the first three slices from the input files. Additionally, only data inside the tropics is included. AUTHOR
NCO manual pages written by Charlie Zender and Brian Mays. REPORTING BUGS
Report bugs to <http://sf.net/bugs/?group_id=3331>. COPYRIGHT
Copyright (C) 1995-2010 Charlie Zender This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU- LAR PURPOSE. SEE ALSO
The full documentation for NCO is maintained as a Texinfo manual called the NCO User's Guide. Because NCO is mathematical in nature, the documentation includes TeX-intensive portions not viewable on character-based displays. Hence the only complete and authoritative versions of the NCO User's Guide are the PDF (recommended), DVI, and Postscript versions at <http://nco.sf.net/nco.pdf>, <http://nco.sf.net/nco.dvi>, and <http://nco.sf.net/nco.ps>, respectively. HTML and XML versions are available at <http://nco.sf.net/nco.html> and <http://nco.sf.net/nco.xml>, respectively. If the info and NCO programs are properly installed at your site, the command info nco should give you access to the complete manual, except for the TeX-intensive portions. HOMEPAGE
The NCO homepage at <http://nco.sf.net> contains more information. NCEA(1)