NAME

       ncra - netCDF Record Averager

SYNTAX

       ncra [-3] [-4] [-6] [-7] [-A] [--bfr sz][-C][-c][--cnk_byt sz][--cnk_dmn nm,sz] [--cnk_map
       map] [--cnk_plc plc] [--cnk_scl sz][-D  dbg_lvl]  [-d  dim,[  min][,[  max]][,  stride[[,[
       subcycle]]]]]  [--dbl|flt]  [-F]  [-G gpe_dsc] [-g grp[,...]]  [-h] [--hdf] [--hdr_pad sz]
       [-L dfl_lvl] [-l path] [--mro] [--msa] [-n loop]  [--no_cll_mth]  [--no_tmp_fl]  [-O]  [-p
       path] [-R] [-r] [--ram_all] [--rec_apn] [-t thr_nbr] [--unn] [-v var[,...]]  [-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 © 1995-2010 Charlie Zender
       This  is  free software; see the source for copying conditions.  There is NO warranty; not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR 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.

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

HOMEPAGE

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

                                                                                          NCRA(1)