NAME

       ncra - netCDF Record Averager

SYNTAX

       ncra  [-3]  [-4] [-5] [-6] [-7] [-A] [--bfr sz_byt][-C][-c][--cnk_byt sz_byt][--cnk_csh sz_byt][--cnk_dmn
       nm,sz_lmn] [--cnk_map map] [--cnk_min sz_byt] [--cnk_plc plc] [--cnk_scl sz_lmn][-D  dbg_lvl]  [-d  dim,[
       min][,[  max]][,  stride[[,[  subcycle]]]]]  [--dbl|flt]  [-F] [--fl_fmt=fmt] [-G gpe_dsc] [-g grp[,...]]
       [--glb att_name= att_val]] [-h] [--hdf] [--hdr_pad sz_byt][--hpss_try] [-L  dfl_lvl]  [-l  path]  [--mro]
       [--msa]  [-N]  [-n loop] [--no_cll_msr] [--no_cll_mth] [--no_frm_trm] [--no_tmp_fl] [-O] [-p path] [--ppc
       var1[, var2[,...]]= prc]] [-R] [-r] [--ram_all] [--rec_apn] [-t thr_nbr] [--unn] [-v var[,...]]  [-w wgt]
       [-X box] [-x] [-y op_typ] input-files output-file

DESCRIPTION

       ncra  averages  record  variables  across  an  arbitrary  number of input files.  The record dimension is
       retained as a degenerate (size 1) dimension in the output variables.

       Input files may vary in size, but each must have a record dimension.   The  record  coordinate,  if  any,
       should  be  monotonic  for  (or  else  non-fatal  warnings  may  be generated).  Hyperslabs of the record
       dimension which include more than one file are handled correctly.  ncra supports the stride  argument  to
       the -d hyperslab option for the record dimension only, stride is not supported for non-record dimensions.

       ncra weights each record (e.g., time slice) in the input-files equally.  ncra does not attempt to see if,
       say, the time coordinate is irregularly spaced and thus would require a weighted average in order to be a
       true time average.

EXAMPLES

       Average files 85.nc, 86.nc,  ...  89.nc along the record dimension, and store the results in 8589.nc:
              ncra 85.nc 86.nc 87.nc 88.nc 89.nc 8589.nc
              ncra 8[56789].nc 8589.nc
              ncra -n 5,2,1 85.nc 8589.nc
       These three methods produce identical answers.

       Assume  the  files  85.nc,  86.nc,  ...  89.nc each contain a record coordinate time of length 12 defined
       such that the third record in 86.nc contains data from March 1986, etc.  NCO knows how to  hyperslab  the
       record dimension across files.  Thus, to average data from December, 1985 through February, 1986:
              ncra -d time,11,13 85.nc 86.nc 87.nc 8512_8602.nc
              ncra -F -d time,12,14 85.nc 86.nc 87.nc 8512_8602.nc
       The  file  87.nc  is  superfluous,  but  does  not cause an error.  The -F turns on the Fortran (1-based)
       indexing convention.  The following uses the stride option to average all the March temperature data from
       multiple input files into a single output file
              ncra -F -d time,3,,12 -v temperature 85.nc 86.nc 87.nc 858687_03.nc

       Assume the time coordinate is incrementally numbered such that January, 1985 = 1 and December, 1989 = 60.
       Assuming ??  only expands to the five desired files, the following averages June, 1985--June, 1989:
              ncra -d time,6.,54. ??.nc 8506_8906.nc

AUTHOR

       NCO manual pages written by Charlie Zender and originally formatted by Brian Mays.

REPORTING BUGS

       Report bugs to <http://sf.net/bugs/?group_id=3331>.

COPYRIGHT

       Copyright © 1995-2018 Charlie Zender
       This is free software; see the source for copying  conditions.   There  is  NO  warranty;  not  even  for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       The full documentation for NCO is maintained as a Texinfo manual called the NCO Users 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 Users 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.

       ncap(1), ncap2(1), ncatted(1), ncbo(1), ncclimo(1),  nces(1),  ncecat(1),  ncflint(1),  ncks(1),  nco(1),
       ncpdq(1), ncra(1), ncrcat(1), ncremap(1), ncrename(1), ncwa(1)

HOMEPAGE

       The NCO homepage at <http://nco.sf.net> contains more information.

                                                                                                         NCRA(1)