time unit conversion

[atul]

Hi

I downloaded data NCEP2 data for creating forcing files manually because opendap server is not working

so now I have file like air.2m.gauss.2011.nc and the time have referencing from year1800 as shown below

have unit in hours ( time:units = "hours since 1800-1-1 00:00:0.0"

double time(time) ;
time:units = "hours since 1800-1-1 00:00:0.0" ;
time:long_name = "Time" ;
time:actual_range = 1849584., 1858338. ;
time:delta_t = "0000-00-00 06:00:00" ;
time:standard_name = "time" ;
time:axis = "T" ;
time:coordinate_defines = "point" ;

I split the data for each month and then created forcing files

then I downloaded ECCO2 data using Yorig=1800 for climatology file and
data is saved in file like ECCO_Y2011M1.nc and so on. the time unit in these file is days

double time(time) ;
time:units = "days since 1-Jan-1800 00:00:0.0" ;


Now I want to convert the unit of variable time from hours to days in downloaded NCEP2 data

( time:units = "hours since 1800-1-1 00:00:0.0" to time:units = "days since 1-Jan-1800 00:00:0.0" ;


how I can do this? is there any command in CDO or in NCO for this kind of conversion.

Thanks in advance

[wilkin]

Since you are not changing the base date (1800-01-01 in both files) only the units from hours to days, you can make the conversion with the NCO tool ncap

Code: Select all

ncap -s 'time=time/24' orig_file new_file

then update the units attributes to keep the metadata accurate

Code: Select all

ncatted -a units,time,c,c,"days since 1800-01-01 00:00:0.0" new_file