Re: [ferret_users] loading 360_day netcdf data

To: Malte Jansen <mjansen@xxxxxxxxxxxxx>
Subject: Re: [ferret_users] loading 360_day netcdf data
From: Ansley Manke <ansley.b.manke@xxxxxxxx>
Date: Tue, 18 Oct 2005 10:02:48 -0700
Cc: Cyndy Chandler <cchandler@xxxxxxxx>, Ferret Users mailing list <oar.pmel.ferret_users@xxxxxxxx>
In-reply-to: <575d28903eb0.43553c71@ifm-geomar.de>
References: <575d28903eb0.43553c71@ifm-geomar.de>
Sender: owner-ferret_users@xxxxxxxxxxxxx
User-agent: Mozilla Thunderbird 1.0.7 (Windows/20050923)

Hi Malte,
Look at the years listed with your data. Is it really the case that the data represents years 0000 to 0011? I am guessing that
there is a time-origin attribute missing from the file. You could fix this with ncatted or with the Ferret command SET AXIS/T0=

The Unix command ncdump -h lists the header of the netcdf file. You might check all the attributes, including the time origin and units.

The SHOW AXIS command you give indicate that Ferret is seeing irregularly-spaced coordinates on the time axis. You can see the coordinate values as they're read from the file with the Ferret LIST command

yes? LIST/L=350:370 t[gt=time], tbox[gt=time]

or with the ncdump -c command

> ncdump -c filename.nc | more

Ansley

Malte Jansen wrote:

Hi all,

using ncatted I managed to tell ferret to use calendar type 360_DAY. But still my data is interpreted in the funny way that ferret uses bigger time boxes for always two days in a year. So the overall Axis span is 3650 "days" instead of 3600. It now looks like this:

yes? show/l=350:365 axis time
name axis # pts start end
TIME TIME 3600 i 04-JAN 00:00 23-FEB-0011 00:00
T0 = 01-JAN-0001 00:00:00
CALENDAR = 360_DAY
Axis span (to cell edges) = 3650
L T TBOX TBOXLO TSTEP (days)
350> 23-DEC 00:00:00 1 22-DEC 12:00:00 352
351> 24-DEC 00:00:00 1 23-DEC 12:00:00 353
352> 25-DEC 00:00:00 1 24-DEC 12:00:00 354
353> 26-DEC 00:00:00 1 25-DEC 12:00:00 355
354> 27-DEC 00:00:00 1 26-DEC 12:00:00 356
355> 28-DEC 00:00:00 1 27-DEC 12:00:00 357
356> 29-DEC 00:00:00 1 28-DEC 12:00:00 358
357> 30-DEC 00:00:00 3.5 29-DEC 12:00:00 359
358> 06-JAN-0002 00:00:00 3.5 03-JAN-0002 00:00:00 365
359> 07-JAN-0002 00:00:00 1 06-JAN-0002 12:00:00 366
360> 08-JAN-0002 00:00:00 1 07-JAN-0002 12:00:00 367
361> 09-JAN-0002 00:00:00 1 08-JAN-0002 12:00:00 368
362> 10-JAN-0002 00:00:00 1 09-JAN-0002 12:00:00 369
363> 11-JAN-0002 00:00:00 1 10-JAN-0002 12:00:00 370
364> 12-JAN-0002 00:00:00 1 11-JAN-0002 12:00:00 371
365> 13-JAN-0002 00:00:00 1 12-JAN-0002 12:00:00 372

Is there anybody who has an Idea what happened and whow to solve that problem?

Thanks
Malte

----- Ursprüngliche Nachricht -----
Von: Cyndy Chandler <cchandler@whoi.edu>
Datum: Freitag, Oktober 14, 2005 4:03 pm
Betreff: Re: [ferret_users] loading 360_day netcdf data

Hello Malte,

I just ran into this yesterday!

You'll want to tell ferret to use a calendar type of 360_DAY I found the info in the User Guide (I think in the section that discusses the time axis).

here's the User Guide example:
Define a calendar axis and regrid an existing variable to this axis:
yes? DEFINE AXIS/CALENDAR=360_DAY/T="15-JAN-1982":"15-DEC-1985":30/UNITS=days tmodelyes? LET twind = uwnd[GT=tmodel@NRST]

I used NCO tools, ncatted, to add the calendar type to the NetCDF file itself:
ncatted -O -a calendar,TIME,o,c,"360_DAY" $nc_file

double TIME(TIME) ;
TIME:units = "days since 01-FEB-1829" ;
TIME:axis = "T" ;
TIME:time_origin = "01-FEB-1829" ;
TIME:calendar = "360_DAY" ;

Then ferret uses that information to define the Time axis.

sho axis/T TIME
name axis # pts start end
TIME TIME 62 r 01-JAN-1940 00:00 01-JAN-
2001 00:00
T0 = 01-FEB-1829 00:00:00
CALENDAR = 360_DAY

hope this helps,
Cyndy

Malte Jansen wrote:

Hello,

I use a (10 years - daily data) netcdf dataset with a 360_day

calendar. When I load it in ferret, ferret seems to interpret it as a gregorian calendar in the following funny way:

yes? use/order=xyzt burnout.nc
yes? show/l=355:370 grid temp
ls: /usr/local/ferret/ext_func/libs/: No such file or directory
GRID GTO1
name axis # pts start

end

LON LONGITUDE 65 r 0E

0E(360)

LAT Y (degrees_nor 32 i- -85.761

85.761

HEIGHT Z (hPa) 3 i- 200

1000

TIME TIME 3600 i 01-JAN 00:00

24-DEC-0010 00:00

L T TBOX TBOXLO

TSTEP (days)

355> 21-DEC 00:00:00 1 20-DEC

12:00:00 354

356> 22-DEC 00:00:00 1 21-DEC

12:00:00 355

357> 23-DEC 00:00:00 1 22-DEC

12:00:00 356

358> 24-DEC 00:00:00 1 23-DEC

12:00:00 357

359> 25-DEC 00:00:00 1 24-DEC

12:00:00 358

360> 26-DEC 00:00:00 3.5 25-DEC

12:00:00 359

361> 01-JAN-0002 00:00:00 3.5 29-DEC 00:00:00

365

362> 02-JAN-0002 00:00:00 1 01-JAN-0002 12:00:00

366> 363> 03-JAN-0002 00:00:00 1 02-JAN-0002 12:00:00 367

364> 04-JAN-0002 00:00:00 1 03-JAN-0002 12:00:00

368> 365> 05-JAN-0002 00:00:00 1 04-JAN-0002 12:00:00 369

366> 06-JAN-0002 00:00:00 1 05-JAN-0002 12:00:00

370> 367> 07-JAN-0002 00:00:00 1 06-JAN-0002 12:00:00 371

368> 08-JAN-0002 00:00:00 1 07-JAN-0002 12:00:00

372> 369> 09-JAN-0002 00:00:00 1 08-JAN-0002 12:00:00 373

370> 10-JAN-0002 00:00:00 1 09-JAN-0002 12:00:00

374>

how can I make Ferret accept my data as 360_day data ?

Thanks
Malte

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Cyndy Chandler | voice: (508) 289-2765
MS #43, WHOI | Office hrs: M-F ~ 9-4
Woods Hole, MA 02543 | FAX: (508) 457-2161
cchandler@whoi.edu | http://www.whoi.edu/people/cchandler
Ocean Carbon and Biogeochemistry Data Management Office
Department of Marine Chemistry and Geochemistry
Woods Hole Oceanographic Institution

References:
- Re: [ferret_users] loading 360_day netcdf data
  - From: Malte Jansen

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