Hi Paulo,I see I missed out a bit in my example. Note, my method does not require you to define a new time axis - I simply re-grid var_yr2 onto the time axis of var_yr1. This works fine so long as the time axis is of the same number of points in both.
Corrected example - using the @asn regridding:use "model_output_year_1.nc"let var_yr2_new_t = var_yr[gt=var_yr1@asn] !"blindy" associate yr1's time axis with y2 data
use "model_output_year_2.nc"
let var_yr1 = var[d=1]
let var_yr2 = var[d=2]
!Plot differences
fill/z=1000/l=1 var_yr1 - var_yr2_new_tOn Aug 11, 2009, at 2:50 PM, Paulo Santiago wrote:
Hi Paul,Thanks for your fast reply.I defined a new time axis and assigned to my variables.define axis/t="15-JAN":"15-DEC":1/units=months mytaxI was wondering if I could solve it without defining a new axis.Cheers,Paulo2009/8/11 Paul Young <Paul.J.Young@xxxxxxxx>
Hi Paulo,
You need to re-grid the data to a common time axis. The simplest way is to re-grid the data from year 2 onto the year 1 time axis. I'll illustrate with a hypothetical ferret session:
use "model_output_year_1.nc"
use "model_output_year_2.nc"
let var_yr1 = var[d=1]
let var_yr2 = var[d=2]
let var_yr2_new_t = var_yr[gt=var_yr1]
!Plot differences
fill/z=1000/l=1 var_yr1 - var_yr2_new_t
----
Take a look at the ferret documentation on re-gridding - ferret makes it quite straightforward for all kinds of re-gridding operations.
http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/Grids-Regions/GRIDS#_VPID_197
Cheers,
Paul
On Aug 11, 2009, at 1:11 PM, Paulo Santiago wrote:
Hi Ferreters,
I wou differences between data with different time axis.
The data are results from the same model (same xyz grid) for different years.
I believe there's a simple and elegant way to do this task with Ferret, but I can't imagine how.
Thanks in advance.
--
Paulo Santiago
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Paulo Santiago
-----Paul YoungChemistry and Climate ProcessesChemical Sciences DivisionNOAA Earth System Research Laboratory325 Broadway R/CSD8Boulder CO 80305-3328USAFax: +1 303-497-5686Email: paul.j.young@xxxxxxxx