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Re: [ferret_users] seasonal anomaly timeseries for 30yrs



Hi,
Yes. Regridding in time needs to take into account the calendar of the axis. There are a number of monthly climatological axes for different calendars, but not seasonal ones. You could define your own seasonal climatology axis based on the appropriate monthly one.

(By the way, starting with Ferret v6.9, you do not need to "use climatological_axes".  The climatological axes are pre-defined within Ferret.)

To get the calendar your dataset uses, 
yes? use precip_MAM_mean.nc
yes? say `precip_MAM,return=calendar`
Then for example if the calendar is  a NOLEAP one, get the upper and lower bounds of the grid boxes for the monthly calendar:

yes? list tboxlo[gt=month_noleap], tboxhi[gt=month_noleap]
             TIME: 01-JAN 00:00 to 01-JAN 00:00 NOLEAP
 Column  1: TBOXLO is TBOXLO (axis MONTH_NOLEAP)
 Column  2: TBOXHI is TBOXHI (axis MONTH_NOLEAP)
                    TBOXLO  TBOXHI
16-JAN 12      /  1:    0.0   31.0
15-FEB 00      /  2:   31.0   59.0
16-MAR 12      /  3:   59.0   90.0
16-APR 00      /  4:   90.0  120.0
16-MAY 12      /  5:  120.0  151.0
16-JUN 00      /  6:  151.0  181.0
16-JUL 12      /  7:  181.0  212.0
16-AUG 12      /  8:  212.0  243.0
16-SEP 00      /  9:  243.0  273.0
16-OCT 12      / 10:  273.0  304.0
16-NOV 00      / 11:  304.0  334.0
16-DEC 12      / 12:  334.0  365.0

And define your own seasonal NOLEAP calendar, using the /EDGES qualifier. See this for defining custom climatological axes: http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/commands-reference/DEFINE#_VPINDEXENTRY_1310
yes? define axis/EDGES/modulo/calendar=noleap/t/t0=1-jan-0000/units=days seasonal_noleap = {0,90,181,273,365}

Then use that for your regridding.  This method would let you define any seasons you want, not necessarily starting with January. 

-Ansley

On 12/1/2015 5:05 AM, Kaduk, Jorg D. (Dr.) wrote:

Hello Julliet,

this sounds more like your time axis is not a calendar ferret recognizes and hence not know how to regrid on the new axis. 

Cheers,

Joerg

 


From: owner-ferret_users@xxxxxxxx [owner-ferret_users@xxxxxxxx] on behalf of afwande juliet [afwandej965@xxxxxxxxx]
Sent: 01 December 2015 01:34
To: Ulrich Jacques Diasso
Cc: ferret_users
Subject: Re: [ferret_users] seasonal anomaly timeseries for 30yrs

hi thanks
I am wondering if space was the problem coz I get the regridding error. I am I supposed to use seasonal regrid or monthly. My data is already seasonal average
yes? use precip_MAM_mean.nc
yes? show data
     currently SET data sets:
    1> ./precip_MAM_mean.nc  (default)
 name     title                             I         J         K         L         M         N
 PRECIP_MAM
          MAM Seasonal Mean precip         1:144     1:72      ...       1:30      ...       ...
       (X=0E:0E(360), Y=90S:90N)
 
yes? use climatological_axes
 *** NOTE: regarding /opt/Ferret/V693/go/climatological_axes.cdf ...
 *** NOTE: Climatological axes SEASONAL_REG, MONTH_REG, MONTH_IRREG, MONTH_GREGORIAN, MONTH_NOLEAP, MONTH_360_DAY, MONTH_ALL_LEAP  defined
yes? cancel data climatological_axes
yes? define grid/like=precip_MAM mygrid
yes? let climatology = precip_MAM[gt=seasonal_reg@mod]
yes? let anomaly = precip_MAM - climatology[gt=mygrid]
yes? plot anomaly[x=22:55@ave,y=-12:22@ave]
 **ERROR: regridding: only @ASN regridding between calendar and
          non-calendar axes: CLIMATOLOGY


On Mon, Nov 30, 2015 at 9:21 AM, Ulrich Jacques Diasso <udiasso@xxxxxxxxx> wrote:
Hi Juliet,
Since anomaly is the variable you want to plot, There should be space between plot and anomaly
like this:
plot anomaly[x=...,y=...]

Cheers


On Mon, Nov 30, 2015 at 4:33 PM, afwande juliet <afwandej965@xxxxxxxxx> wrote:
Dear users,
I have GPCP.nc data for 44years. I have used seasonal mask to create data precip_MAM_mean.nc that has only 30yrs data for MAM season only.

Now I want to plot the timeseries anomaly for this data as below  but get the error. Can someone help point out difference . I have tried to follow this example http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_99/msg00291.html
but not able.
[anyuola@login01 validation]$ ferret
  NOAA/PMEL TMAP
  FERRET v6.93 
  Linux 2.6.32-504.el6.x86_64 64-bit - 11/13/14
   1-Dec-15 00:14    

yes? use precip_MAM_mean.nc
yes? show data grids
yes? show data
     currently SET data sets:
    1> ./precip_MAM_mean.nc  (default)
 name     title                             I         J         K         L         M         N
 PRECIP_MAM
          MAM Seasonal Mean precip         1:144     1:72      ...       1:30      ...       ...
       (X=0E:0E(360), Y=90S:90N)
 
yes? show grids precip_mam
    GRID GPN1
 name       axis              # pts   start                end
 LON       LONGITUDE          144mr   1.25E                1.25W
 LAT       LATITUDE            72 r   88.75S               88.75N
 normal    Z
 TYEAR     T (years)           30 r   1980                 2009
 normal    E
 normal    F
yes? use climatological_axes
 *** NOTE: regarding /opt/Ferret/V693/go/climatological_axes.cdf ...
 *** NOTE: Climatological axes SEASONAL_REG, MONTH_REG, MONTH_IRREG, MONTH_GREGORIAN, MONTH_NOLEAP, MONTH_360_DAY, MONTH_ALL_LEAP  defined
yes? cancel data climatological_axes
yes? define grid/like=precip_MAM mygrid
yes? let climatology = precip_MAM[gt=seasonal_reg@mod]
yes? let anomaly = precip_MAM - climatology[gt=mygrid]
yes? plot/anomaly [x=22:55@ave,y=-12:22@ave]
 **ERROR: unknown command qualifier: anomaly
yes? plot anomaly [x=22:55@ave,y=-12:22@ave]
 **ERROR: command syntax: anomaly [x=22:55@ave,y=-12:22@ave]
          omaly [x=




--
Ulrich Jacques DIASSO
Climate Change assessment Expert
Montoring for Environment and Security in Africa (MESA)
African Centre of Meteorological Applications for Development (ACMAD)
85, Avenue des Ministeres
Niamey -  NIGER
Cell Phone: +227 91 63 80 91
                       +226 76 17 76 00




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