Re: [ferret_users] replace data by inserting climatology

Thanks Russ, my apologies for getting back late.
But i suddenly i got something very weired in ferret while making climatology and regriding it to original variable time axis. while regriding the climatology to the original variable time axis lets say test_cli=temp_cli[gt=sst], then the values are not exactly the same values of climatology. i dont know what to do about this.

is it a bug that ferret is having so something i am doing wrong. please help me out.

i am attaching my jnl file and here i am giving the description for my data.

name     title                                                I         J         K           L         M         N
SST      sea surface temperature (degc)   1:360     1:180     ...       1:1368    ...      ...

GRID GPP1
name       axis                # pts              start                 end
LON       LONGITUDE       360mr 179.5W(-179.5)       179.5E
LAT       LATITUDE           180 r              89.5S                89.5N
normal    Z
TIME      TIME                1368 i     01-JAN-1901 00:00    01-DEC-2014 00:00
normal    E
normal    F

list/x=85/y=16/l=1:24    test_cli
             VARIABLE : TEMP_CLI[GT=SST]
             FILENAME : sstnew.nc
             SUBSET   : 24 points (TIME)
             LONGITUDE: 84.5E
             LATITUDE : 15.5N
                        84.5E
                       265
01-JAN-1901 00 / 1: 26.37
01-FEB-1901 00 / 2: 26.74
01-MAR-1901 00 / 3: 27.74
01-APR-1901 00 / 4: 28.98
01-MAY-1901 00 / 5: 29.62
01-JUN-1901 00 / 6: 29.40
01-JUL-1901 00 / 7: 28.82
01-AUG-1901 00 / 8: 28.53
01-SEP-1901 00 / 9: 28.64
01-OCT-1901 00 / 10: 28.60
01-NOV-1901 00 / 11: 27.89
01-DEC-1901 00 / 12: 26.91
01-JAN-1902 00 / 13: 26.37
01-FEB-1902 00 / 14: 26.73
01-MAR-1902 00 / 15: 27.73
01-APR-1902 00 / 16: 28.98
01-MAY-1902 00 / 17: 29.62
01-JUN-1902 00 / 18: 29.41
01-JUL-1902 00 / 19: 28.82
01-AUG-1902 00 / 20: 28.53
01-SEP-1902 00 / 21: 28.64
01-OCT-1902 00 / 22: 28.60
01-NOV-1902 00 / 23: 27.90
01-DEC-1902 00 / 24: 26.91

list/x=85/y=16/l=1:24     temp_cli
             VARIABLE : SST[GT=MONTH_GREGORIAN@MOD]
             FILENAME : sstnew.nc
             SUBSET   : 24 points (TIME)
             LONGITUDE: 84.5E
             LATITUDE : 15.5N
                        84.5E
                       265
16-JAN 12      / 1: 26.32
15-FEB 02      / 2: 27.11
15-MAR 17      / 3: 28.45
15-APR 05      / 4: 29.52
15-MAY 17      / 5: 29.73
15-JUN 05      / 6: 29.08
15-JUL 17      / 7: 28.54
15-AUG 17      / 8: 28.52
15-SEP 05      / 9: 28.77
15-OCT 17      / 10: 28.42
15-NOV 05      / 11: 27.37
15-DEC 17      / 12: 26.42

test_cli is the regridded variable and temp_cli is the climatology.

i hope this is some permanent solution to get rid of this problem. as far i can understand as my data is starting from 01-jan-1901 so the day is 01 but my climatology stat from 16-jan so the day is 16 so while regriding the ferret is doing something that i am not able to understand.

i hope i will get the solution as soon as possible. thanks in advance.

regards

On Mon, Jul 4, 2016 at 6:24 AM, Russ Fiedler <russell.fiedler@xxxxxxxx> wrote:

Hi,

You can mask according to time as follows:

! Expand climatology out to full axis.

let sst_clim=temp_cli_nino[gt=sst]

! Mask according to time

let sst_comb = if t ge `t[t=01-sep-1997,gt=sst]` and t le `t[t=31-dec-1997,gt=sst]` then sst_clim else sst

plot/x=180/y=0 sst,sst_clim,sst_comb

Cheers,
Russ

On 01/07/16 14:38, saurabh rathore wrote:

Dear Ansley,

my purpose of masking is to mask SST values of SEPT, OCT, NOV, DEC of year 1997 only. i don't want to mask any other months of other years except these 4 months of 1997 and after masking i want to place climatological values of SEPT, OCT, NOV, DEC for the above months of 1997.

i tried but unable to do so.

regards, saurabh

On Fri, Jul 1, 2016 at 12:05 AM, Ansley C. Manke <ansley.b.manke@xxxxxxxx> wrote:

Hi Saurabh

This can be done with the "masking" capability.
http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/variables-xpressions/XPRESSIONS#_VPID_181

Take the example in the FAQ on climatologies.
http://ferret.pmel.noaa.gov/Ferret/faq/how-do-i-calculate-climatologies-and-climatological-anomalies

Simplifying some of the syntax in that example - define a climatology. Then go on to define a variable which replaces some values of the file variable with that climatology.

! open a dataset and define the climatology
yes? SET DATA monthly_navy_winds
yes? LET uwnd_climatology = uwnd[GT=month_reg@MOD]

! Plot the data and the climatology together.
! Using /VLIM will make it easier to compare this plot with the next one.

yes? set view upper
yes? PLOT/X=180/Y=40/T=15-jan-1983:15-jan-1991/vlim=-6:16 uwnd
yes? PLOT/OVER/X=180/Y=40/T=15-jan-1983:15-jan-1991 uwnd_climatology

! Now define the new variable with some values of unwd replaced by the climatology. ! Plot the original variable, then overlay the new one.
yes? let uwnd_replace = if uwnd gt 8 then uwnd_climatology else uwnd
yes? set view lower
yes? PLOT/X=180/Y=40/T=15-jan-1983:15-jan-1991/vlim=-6:16 uwnd
yes? PLOT/OVER/X=180/Y=40/T=15-jan-1983:15-jan-1991 uwnd_replace

(you'll see some NOTEs about ambiguous coordinates when the 'replace' variable is computed. This is fine.)

So the only thing left is for you to find a way to define a "mask" variable which is on the time axis of SST, and has the value of say, 1 at the times when you want to keep the SST time series data, and 0 when you want to make the replacement.

   yes? let replace_var = if mask eq 1 then SST[d=1] else TEMP_CLI[d=2]

-Ansley

On 6/30/2016 7:31 AM, saurabh rathore wrote:

Dear Ferreters,

i am facing a problem in replacing some particular time steps data with the Climatological data of the same months.

for example i am having SST data from 1901-2014 in which i want to replace September, October, November and December of 1997 and January, February of 1998 from the climatological values of the same months i.e. Sep-1997 by Sept-Climatological value, Oct-1997 by Oct-Climatological value and so on.

this is my data description

SST data 1901-2014
name     title                                                I         J         K         L         M         N
SST      sea surface temperature (degc)    1:360     1:180     ...      1:1368    ...     ...

Climatology
name                                          title                             I           J         K         L         M         N
TEMP_CLI NINO1[GT=MONTH_GREGORIAN@MOD]    1:360     1:180     ...       1:12      ...       ...

i hope i made my problem clear and i believe i will get the solution.

regards, saurabh

--

REGARDS

Saurabh Rathore

Research Scholar (PhD.)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434

--

REGARDS

Saurabh Rathore

Research Scholar (PhD.)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434

REGARDS

Saurabh Rathore

Research Scholar (PhD.)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434