How to read pentad precipitation data (by Xie-Arkin) from GrADS?

[Li Huang]

Dear all,

I am a new GrADS user. I got Xie-Arkin pentad precipitation data (not the
monthly mean) from http://www.cdc.noaa.gov/cdc/data.cmap.html, and opened it
by "sdfopen precip.pentad.mean.nc", which works. But the time coordinate
varies linearly. In a leap year, for example 2000, the subperiod of Feb 25 -
Mar 1 in the original file has 6 days rather than 5. It was not treated in
this way by sdfopen command in GrADS, and as far as I know the xdfopen
command only works with linearly increased dates. How can I open the file
correctly?

I would be grateful for any help from you.

Li Huang

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P.S. the output from "q config" as follows.

Config: v1.8SL11 32-bit little-endian readline sdf/xdf netcdf lats printim

Grid Analysis and Display System (GrADS) Version 1.8SL11
Copyright (c) 1988-2001 by Brian Doty
Center for Ocean-Land-Atmosphere Studies
Institute for Global Environment and Society

Built on 12/05/02 by dasilva (CYGWIN_NT-5.0 1.3.15(0.63/3/2))

This version of GrADS has been configured with the following options:

   o This is a 32-bit LITTLE ENDIAN machine version.
   o Command line editing (readline) ENABLED.
   o CIRES/CDC (http://www.cdc.noaa.gov) SDF/XDF interface ENABLED.
     Use sdfopen or xdfopen to read NetCDF files; this version is NOT
     configured to read HDF-SDS files.
   o URI DODS interface DISABLED.
   o PCMDI (http://www-pcmdi.llnl.gov) LATS interface ENABLED.
     This version is configured to write GRIB and NetCDF files.
   o DAO (http://dao.gsfc.nasa.gov) Athena Widget GUI DISABLED.
   o NRL/DAO/PCMDI XA or ImageMagick Image Output DISABLED.
   o printim command for direct png/gif output ENABLED.
     (via the GD Library -- http://www.boutell.com/gd)