Re: [ferret_users] difference in trend computation from CDO and from ferret

[Pratik Kad <pratikkad17@xxxxxxxxx>]

Hi Saurabh,

As we know ferret is sensitive to the time axis. by default, it takes the unit of a given parameter, So you need to the checkout time unit of netCDF file. Then multiply by that factor as per your interest.

Here your file has time unit in months ( which gives trend per month); Hence you need to multiply by 12 then you will get trend per year.  

Regards
Pratik

On Wed, Jun 19, 2019 at 12:09 PM saurabh rathore <rohitsrb2020@xxxxxxxxx> wrote:

Dear Ferreters,

G'day

I am having very strange problem in computation of trend (slope). I am replotting my data after 1 year or so and I want to compute trend from it. I am having my data from 2005-2015.

Here is the attached data.

from ferret I used this script

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

use ohc-ferret.nc

let p=t[gt=ohcg1]

let q=ohcg1

go regresst

fill/lev=(-inf)(-20,20,4)(inf)/pal=blue_orange slope*10^-7*12

frame/file=test-ferret.png

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!