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How to convert time axis into relative time axis?

Added by Jinyan Song over 1 year ago

+++++++my file time axis is fllowing

I want to convert time axis into relative time using the cdo option.

my operation:

How to convert the time axis into relative time axis?

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clipboard-202305281318-lro6s.png (42.5 KB) clipboard-202305281318-lro6s.png
clipboard-202305281319-5j95k.png (39.4 KB) clipboard-202305281319-5j95k.png
clipboard-202305281321-xukdg.png (20.1 KB) clipboard-202305281321-xukdg.png
Land_and_Ocean_select.nc (15.4 MB) Land_and_Ocean_select.nc

Replies (1)

RE: How to convert time axis into relative time axis? - Added by Karin Meier-Fleischer over 1 year ago

Hi Jinyan,

your file contains 4 years of monthly data. To convert the time dimension to relative time you have to set the time axis and reference time, for example:

cdo -r -settaxis,1850-01-01,12:00:00,1month -setreftime,1850-01-01,12:00:00,1month Land_and_Ocean_select.nc Land_and_Ocean_select_reftime.nc

The result:

cdo sinfon Land_and_Ocean_select_reftime.nc 

   File format : NetCDF4
    -1 : Institut Source   T Steptype Levels Num    Points Num Dtype : Parameter name
     1 : unknown  unknown  c instant       1   1     64800   1  F64  : land_mask     
     2 : unknown  unknown  v instant       1   1     64800   1  F32  : temperature   
     3 : unknown  unknown  c instant      12   2     64800   1  F32  : climatology   
   Grid coordinates :
     1 : lonlat                   : points=64800 (360x180)
                        longitude : -179.5 to 179.5 by 1 degrees_east  circular
                         latitude : -89.5 to 89.5 by 1 degrees_north
   Vertical coordinates :
     1 : surface                  : levels=1
     2 : generic                  : levels=12
   Time coordinate :
                             time : 48 steps
     RefTime =  1850-01-01 12:00:00  Units = months  Calendar = proleptic_gregorian
  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss  YYYY-MM-DD hh:mm:ss
  1850-01-01 12:00:00  1850-02-01 12:00:00  1850-03-01 12:00:00  1850-04-01 12:00:00
  1850-05-01 12:00:00  1850-06-01 12:00:00  1850-07-01 12:00:00  1850-08-01 12:00:00
  1850-09-01 12:00:00  1850-10-01 12:00:00  1850-11-01 12:00:00  1850-12-01 12:00:00
  1851-01-01 12:00:00  1851-02-01 12:00:00  1851-03-01 12:00:00  1851-04-01 12:00:00
  1851-05-01 12:00:00  1851-06-01 12:00:00  1851-07-01 12:00:00  1851-08-01 12:00:00
  1851-09-01 12:00:00  1851-10-01 12:00:00  1851-11-01 12:00:00  1851-12-01 12:00:00
  1852-01-01 12:00:00  1852-02-01 12:00:00  1852-03-01 12:00:00  1852-04-01 12:00:00
  1852-05-01 12:00:00  1852-06-01 12:00:00  1852-07-01 12:00:00  1852-08-01 12:00:00
  1852-09-01 12:00:00  1852-10-01 12:00:00  1852-11-01 12:00:00  1852-12-01 12:00:00
  1853-01-01 12:00:00  1853-02-01 12:00:00  1853-03-01 12:00:00  1853-04-01 12:00:00
  1853-05-01 12:00:00  1853-06-01 12:00:00  1853-07-01 12:00:00  1853-08-01 12:00:00
  1853-09-01 12:00:00  1853-10-01 12:00:00  1853-11-01 12:00:00  1853-12-01 12:00:00
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