Re: [ferret_users] Averaging multi variables

[Saat Mubarrok <saatmubarrok@xxxxxxxxx>]

Thank you Mr. Saurabh,

After a long fight, your solution is what I need.

Best,

Saat M.

On Tue, Jul 23, 2019 at 9:47 AM saurabh rathore <rohitsrb2020@xxxxxxxxx> wrote:

Hi Saat,

G'day

There is a function in CDO called as "ensmean" which can solve your problem if you want to average (ensemble mean) the variable/s. 

let suppose you have files as sst1.nc sst2.nc sst3.nc ......... sstn.nc

you can do like this using the wild card in CDO.

cdo -r -f nc4 ensmean sst*.nc ensemble_mean_output.nc

here *.nc covers all the files that you want to average with the help of * wild card. You have to be careful while using wild card " * " because if you are using *.nc it will take all the netcdf files present in the folder. So better that you make a separate folder that contains only those files that you want to use for a particular operation. 

this is the direct way to do mean of variable/s across multiple files. 

let me know if this doesn't work. we will try something else also with the help of ferret.

cheers, saurabh

On Tue, Jul 23, 2019 at 10:21 AM Saat Mubarrok <saatmubarrok@xxxxxxxxx> wrote:

Dear Satyesh,

Thank you very much for your reply.

But if I have more variables like 30 or even 100, should I do manually also?

Best regards,

Saat M.

On Mon, Jul 22, 2019 at 8:00 PM Satyesh Ghetiya <satyeshghetiya@xxxxxxxxx> wrote:

Following types of expressions are not allowed in Ferret unlike other programming languages : "let ave=ave+2"

For the loop, you may do this:

repeat/name=me/range=1:6 (\

let tempid=temp[i=`me`];\
use "`tempid`.temp.regrid.nc";\

)

let sst_ave=(sst[d=1]+sst[d=2]+sst[d=3]+sst[d=4]+sst[d=5]+sst[d=6])/6

This is usual way for limited number of variables (e.g. here 6)

Regards,

G Satyesh

On Mon, Jul 22, 2019 at 2:24 PM Saat Mubarrok <saatmubarrok@xxxxxxxxx> wrote:

Dear community,

I am new to ferret and trying to do a summation using repeat. Let say I have 6 datasets with same variable on it (sst). I want to averaging those variables. What is the best method to do that in ferret?

set region/x=20e:120e/y=30s:30n/k=1

let temp= {"2002","2003","2004","2006","2007","2010"}

repeat/name=me/range=1:6 (\
let tempid=temp[i=`me`];\
use "`tempid`.temp.regrid.nc";\

let ave`me`=sst[d=`me`];\

let ave=ave+ave`me`;\

)

fill/nolab/lev=(-inf)(23,32,2)(inf) ave/6

the error I get is 

**ERROR: stack overflow

Any lead is much appreciate. Thank you

Saat M.

--

REGARDS

Saurabh Rathore

Research Scholar (PhD.)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434