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_min sz] [--cnk_plc plc] [--cnk_scl sz][-D dbg_lvl] [-d dim,[  min][,[  max]][,
       stride[[,[  subcycle]]]]]  [--dbl|flt]  [-F] [-G gpe_dsc] [-g grp[,...]]  [--glb att_name=
       att_val]] [-h] [--hdf] [--hdr_pad sz] [-L dfl_lvl] [-l  path]  [--mro]  [--msa]  [-N]  [-n
       loop]  [--no_cll_mth]  [--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 © 1995-2016 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), 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)