Re: [ferret_users] Time axis in monthly data using desc files

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi -
You will need to create a true monthly time axis and regrid your data to it.  The descriptor file framework will create a correct axis based on the files you list in the descriptor, but it doesn't have a way to define the "edges" between grid cells.

There is some discussion of defining monthly axes in the Users Guide, see "DEFINE AXIS/EDGES".  Do you want a Julian calendar, or Ferret's default Proleptic Gregorian one? 

Ansley

On Mon, Jun 11, 2012 at 8:15 AM, Ge Peng <ge.peng@xxxxxxxx> wrote:

Hello,

I have monthly nc files from Jan 1979 to Dec 2007 that I would like to
use desc files to load.

Using the following:

&BACKGROUND_RECORD
  D_TITLE            = ''
  D_T0TIME           = '15-JAN-1978 00:00:00'
  D_TIME_UNIT        = 2629800
  D_TIME_MODULO      = .FALSE.
  D_CALTYPE          = 'GREGORIAN'
/

I got the time axis as following:

for year 1988:
15-JAN-1988 12:00
14-FEB-1988 22:30
16-MAR-1988 09:00
15-APR-1988 19:30
16-MAY-1988 06:00
15-JUN-1988 16:30
16-JUL-1988 03:00
15-AUG-1988 13:30
15-SEP-1988 00:00
15-OCT-1988 10:30
14-NOV-1988 21:00
15-DEC-1988 07:30

for year 2007:
15-JAN-2007 06:00
14-FEB-2007 16:30
17-MAR-2007 03:00
16-APR-2007 13:30
17-MAY-2007 00:00
16-JUN-2007 10:30
16-JUL-2007 21:00
16-AUG-2007 07:30
15-SEP-2007 18:00
16-OCT-2007 04:30
15-NOV-2007 15:00
16-DEC-2007 01:30

Noting that the days and hours in the resultant time axis. (Same if
using Julian.)

I would like to have days on either 01 or 15 of each month and hours
on either 00 or 12 of each day. Is there a way to achieve that without
having to regrid after loading the files?

Thanks,

--- Peng

P.S.: As this is a high level question that is independent of data
files in my mind, I do not include any info on data or the scripts for
generating the desc files. However, let me know if you do need those
info to help me with my question.