NAME

       ncra - netCDF Record Averager

SYNTAX

       ncra  [-3]  [-4]  [-5]  [-6]  [-7]  [-A]  [--bfr sz_byt] [-C] [-c] [--cb y1,y2,m1,m2,tpd] [--cmp cmp_sng]
       [--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[[,[  interleave]]]]]]
       [--dbl|flt] [-F] [--fl_fmt=fmt] [-G gpe_dsc] [-g grp[,...]]  [--glb att_name= att_val]] [-H] [-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]]  [--prm_int]
       [--prw  wgt_arr]  [-R] [-r] [--ram_all] [--rec_apn] [-t thr_nbr] [--uio] [--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-present 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.

       ncap2(1), ncatted(1), ncbo(1), ncclimo(1), nces(1), ncecat(1), ncflint(1), ncz2psx(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)