course-idma2016/matlab/idma_area_mean.m

function [mn]=idma_area_mean(fld,msk);
% IDMA_AREA_MEAN computes area-weighted average of a
%    field (fld; 2D or 3D) over a region defined by 
%    a 0/1 mask (msk). Both fld and msk are of 
%    the gcmfaces class. If fld has a third dimension
%    (e.g., for depth or time) then mn is a vector
%
% Example: box_l=[-180 -140]; box_L=[-10 10]-30;
%          msk=(mygrid.XC>=box_l(1)&mygrid.XC<box_l(2)&...
%               mygrid.YC>=box_L(1)&mygrid.YC<box_L(2));
%
%          fileName='nctiles_climatology/THETA/THETA'; 
%          fldName='THETA';
%          fld=read_nctiles(fileName,fldName,1);
%          fld=fld.*mygrid.mskC;
%
%          [mn]=idma_area_mean(fld,msk);
%          figureL; plot(mn,mygrid.RC);

gcmfaces_global;

n=size(fld{1},3);
mn=NaN*zeros(1,n);

racmsk=msk.*mygrid.RAC;
racmsk=repmat(racmsk,[1 1 n]);
racmsk(isnan(fld))=0;

for k=1:n;
    mn(k)=nansum(racmsk(:,:,k).*fld(:,:,k))/nansum(racmsk(:,:,k));
end;


1	gforget	1.1	function [mn]=idma_area_mean(fld,msk);
2			% IDMA_AREA_MEAN computes area-weighted average of a
3			% field (fld; 2D or 3D) over a region defined by
4			% a 0/1 mask (msk). Both fld and msk are of
5			% the gcmfaces class. If fld has a third dimension
6			% (e.g., for depth or time) then mn is a vector
7			%
8			% Example: box_l=[-180 -140]; box_L=[-10 10]-30;
9			% msk=(mygrid.XC>=box_l(1)&mygrid.XC<box_l(2)&...
10			% mygrid.YC>=box_L(1)&mygrid.YC<box_L(2));
11			%
12			% fileName='nctiles_climatology/THETA/THETA';
13			% fldName='THETA';
14			% fld=read_nctiles(fileName,fldName,1);
15			% fld=fld.*mygrid.mskC;
16			%
17			% [mn]=idma_area_mean(fld,msk);
18			% figureL; plot(mn,mygrid.RC);
19
20			gcmfaces_global;
21
22			n=size(fld{1},3);
23			mn=NaN*zeros(1,n);
24
25			racmsk=msk.*mygrid.RAC;
26			racmsk=repmat(racmsk,[1 1 n]);
27			racmsk(isnan(fld))=0;
28
29			for k=1:n;
30			mn(k)=nansum(racmsk(:,:,k).*fld(:,:,k))/nansum(racmsk(:,:,k));
31			end;
32
33