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<p>Hello dear ncl-users,</p>
<p>I would like to know how to remove the ensemble mean from the
corresponding time of each ensemble member, the method i used is
not correct as it performs time average and i want to do ensemble
average. The idea is to calculate ensemble mean each year (this
also removes the seasonal cycle). </p>
<p>my original data is x= time | 240] x [ens | 100] x [lat | 45] x
[lon | 90]</p>
<p>;First method</p>
<p> dimx = dimsizes(x)<br>
ntim = dimx(0) ; 240<br>
nens = dimx(1) ; 100<br>
nlat = dimx(2) ; 45<br>
mlon = dimx(3) ; 90<br>
<br>
<br>
x@_FillValue = -9.96921e+36<br>
ens_mean1=dim_avg_n_Wrap(x,1)<br>
printVarSummary(ens_mean1) ;[time | 240] x [lat | 45] x
[lon | 90]<br>
<br>
x1 = x<br>
do n=0,nens-1<br>
hist_anom1(:,n,:,:) = hist_anom(:,n,:,:) - ens_mean1<br>
end do<br>
</p>
<p>;=second
method=================================================================<br>
; Compute monthly anomalies from the mean climatology to remove
seasonal cycle or to use<br>
; rmMonAnnCycTLL (x) Removes the annual cycle from monthly data
and subtracts the long term means from each month.<br>
;==================================================================<br>
<br>
xClm = clmMonTLLL(x) ;
climatologies for each ensemble member<br>
printVarSummary(xClm) ; [month |
12] x [ens | 100] x [lat | 45] x [lon | 90]<br>
printMinMax(xClm,0) ; :
min=-226.887 max=161.211cm<br>
print("============")<br>
<br>
xAnom = calcMonAnomTLLL(x,xClm) ; anomalies
from each ensemble member climatology<br>
printVarSummary(xAnom) ; [time |
240] x [ens | 100] x [lat | 45] x [lon | 90]<br>
printMinMax(xAnom,0) ;
min=-0.737722 max=0.83556<br>
print("============")<br>
</p>
<p>;3rd method<br>
;==================================================================<br>
xClmMonEns = new((/nmos,nlat,mlon/), typeof(x), x@_FillValue)<br>
do nmo=0,nmos-1<br>
work := reshape(x(nmo::nmos,:,:,:) ,(/nyrs*nens,nlat,mlon/))<br>
xStat = dim_stat4_n(work,0 ) ; (4,nlat,mlon)<br>
xClmMonEns(nmo,:,:) = xStat(0,:,:)<br>
end do<br>
; meta data<br>
xClmMonEns@long_name = "Monthly Climatology"<br>
xClmMonEns@LONG_NAME = "Monthly Climatology over all Ensemble
Members"<br>
xClmMonEns@units = x@units<br>
copy_VarCoords(x(0,0,:,:), xClmMonEns(0,:,:))<br>
xClmMonEns!0 = "month"<br>
printVarSummary(xClmMonEns)<br>
print("-----")<br>
printMinMax(xClmMonEns,0)<br>
<br>
;==================================================================<br>
; Remove the ensemble monthly climatology from each ensemble
member
;==================================================================<br>
printVarSummary(x)<br>
printMinMax(x,0)
print("===")<br>
<br>
xAnom = x<br>
do nt=0,ntim-1<br>
nmo = nt%12<br>
do ne=0,nens-1<br>
xAnom(nt,ne,:,:) = (/ x(nt,ne,:,:) - xClmMonEns(nmo,:,:)
/) ; anomaly array<br>
end do<br>
end do<br>
xAnom@long_name = "Anomalies from Climatology"<br>
<br>
printVarSummary(xAnom)<br>
printMinMax(xAnom,0)<br>
print("===")<br>
</p>
<div class="moz-cite-prefix">On 6/12/2020 2:06 PM, Rashed Mahmood
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOmfQPpEhqfDXJx7uPy+tpJ+GLeiqwY89EwQ+WOufS=b13YuSQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div>Please add ncl-talk in subsequent messages...</div>
<div><br>
</div>
<div>In that case, my suggestion in previous message should
work.</div>
<div><br>
</div>
<div>Rashe<br>
</div>
</div>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Jun 12, 2020 at 1:55
PM Sri nandini <<a href="mailto:bax8609@uni-hamburg.de"
moz-do-not-send="true">bax8609@uni-hamburg.de</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Thank you.</p>
<p>I wish to remove the ensemble mean from each
corresponding time of each ensemble.</p>
<p>Sri<br>
</p>
<div>On 12.06.20 13:48, Rashed Mahmood wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>If you just want to remove ensemble mean then you
could do the following:</div>
<div><br>
</div>
<div>x_new = x</div>
<div> ens_mean = dim_avg_n_Wrap(x,1) <br>
</div>
<div>do n=0,nens-1</div>
<div> x_new(:,n,:,:) = x(:,n,:,:) - ens_mean <br>
</div>
<div>end do</div>
<div><br>
</div>
<div>However, please make sure that this is what you
want!, it is up to you to decide and know what you are
trying to accomplish here. Your variable names suggest
that there could be some confusion...</div>
<div><br>
</div>
<div>Cheers,</div>
<div>Rashed<br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Jun 12, 2020
at 12:50 PM Sri nandini via ncl-talk <<a
href="mailto:ncl-talk@mailman.ucar.edu"
target="_blank" moz-do-not-send="true">ncl-talk@mailman.ucar.edu</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px
0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hello dear
ncl-users,<br>
<br>
I want to know the best way to remove the ensemble
mean from the <br>
corresponding time of each ensemble member. Can
someone tell me if the <br>
following code is correct? i do not get any error but
i wanted to be <br>
sure of the method.<br>
<br>
Thanx in advance<br>
<br>
Sri<br>
<br>
;==================================================================<br>
; Remove the ensemble mean from each ensemble member<br>
;==================================================================<br>
dimx = dimsizes(x)<br>
ntim = dimx(0) ; 240<br>
nens = dimx(1) ; 100<br>
nlat = dimx(2) ; 45<br>
mlon = dimx(3) ; 90<br>
<br>
nmos = 12<br>
nyrs = ntim/nmos ; 21<br>
<br>
printVarSummary(x) ;[time | 240] x [ens |
100] x [lat | 45] x [lon | 90]<br>
ens_mean=dim_avg_n_Wrap(x,1)<br>
printVarSummary(ens_mean);[time | 240] x [lat |
45] x [lon | 90]<br>
<br>
detrended_x = x<br>
do nt=0,ntim-1<br>
nmo = nt%12<br>
do ne=0,nens-1<br>
detrended_x(nt,ne,:,:) = (/ x(nt,ne,:,:) -
ens_mean(nmo,:,:) /) ; detrended array<br>
end do<br>
end do<br>
detrended_x@long_name = “Ensemble mean removed”<br>
<br>
printVarSummary(detrended_x)<br>
[time | 240] x [ens | 100] x [lat | 45] x [lon |
90]<br>
<br>
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