Re: Error when making composite of wind anomaly....

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Mon Dec 21 2009 - 09:18:03 MST

There is nothing wrong. You have removed the mean correctly.

If you create a "composite" by adding all the differences then the answer
should be zero [10^-7, 10^-8 are numeric zero].

Incidently, the following creates the anomalies directly

http://www.ncl.ucar.edu/Document/Functions/Contributed/dim_rmvmean_n_Wrap.shtml

Sabeerali(sebi) wrote:
> Hellooo,
>
> I have ncep/ncar uwnd of dimension(time=24,lat=73,lon=144)..I
> have to find the time average and remove that from my original data
> and find the anomaly..The maximaum and minimum value of my anomaly
> data are 25.43 and -36.15 respectively. After that I have to make
> composite of anomaly..But when I make composite of anomaly(anom_compo
> in my script) I am getting values of the order of 10^-7 or 10^-8...I
> am attaching my script here....Where I am wrong?...
>
> Any help would be appreciated...
> Thanking You
>
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> begin
> ;**************************************************************
> in1=addfile("uv850","r")
> uwnd=in1->uwnd
>
> ;*****************************************************
> uwndanom=new((/24,73,144/),float)
> meanu=new((/1,73,144/),float)
>
> meanu(0,:,:)=dim_avg_n_Wrap(uwnd,0)
>
> do t=0,23
> uwndanom(t,:,:)=uwnd(t,:,:)-meanu(0,:,:)
> end do
>
> copy_VarMeta(uwnd,uwndanom)
> anom_compo=dim_avg_n_Wrap(uwndanom,0)
> print(anom_compo)
> end
> --
> **********************************
> Sabeerali C T
> Climate and Global Modeling Division
> Indian Institute of Tropical Meteorology
> Pashan, Pune, 411 008
> ****************************************
> ------------------------------------------------------------------------
>
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>

-- 
======================================================
Dennis J. Shea                  tel: 303-497-1361    |
P.O. Box 3000                   fax: 303-497-1333    |
Climate Analysis Section                             |
Climate & Global Dynamics Div.                       |
National Center for Atmospheric Research             |
Boulder, CO  80307                                   |
USA                        email: shea 'at' ucar.edu |
======================================================
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk
Received on Mon Dec 21 09:19:14 2009

This archive was generated by hypermail 2.1.8 : Mon Dec 21 2009 - 09:22:56 MST