matlab_class/gcmfaces_calc/calc_MeridionalTransport.m

function [FLD]=calc_MeridionalTransport(fldU,fldV,varargin);
%object:    compute net meridional transports of e.g. heat or fresh water
%inputs:    fldU and fldV are the fields of grid point transport
%optional:  doScaleWithArea, if 1 then multiply fldU by
%               dyg.*drf and accordingly for fldV.
%               If 0 (default) then it is assumed that those factors
%               have already been included (e.g. by pkg/diagnostics).
%output:    FLD is the integrated transport vector (one point per latitude).
%
%notes:     mygrid.LATS_MASKS is the set of quasi longitudinal lines along which
%               transports will integrated, as computed in gcmfaces_lines_zonal

global mygrid;

if nargin==3; doScaleWithArea=varargin{1}; else; doScaleWithArea=0; end;

%initialize output:
n3=max(size(fldU.f1,3),1); n4=max(size(fldV.f1,4),1);
FLD=NaN*squeeze(zeros(length(mygrid.LATS_MASKS),n4));

%prepare fldU/fldV:
fldU(isnan(fldU))=0; fldV(isnan(fldV))=0;

if doScaleWithArea;
   dxg=mk3D(mygrid.DXG,fldU); dyg=mk3D(mygrid.DYG,fldU); drf=mk3D(mygrid.DRF,fldU);
   for k4=1:n4;
   fldU(:,:,:,k4)=fldU(:,:,:,k4).*dyg.*drf;
   fldV(:,:,:,k4)=fldV(:,:,:,k4).*dxg.*drf;
   end;
end;

%use array format to speed up computation below:
fldU=convert2array(fldU); fldV=convert2array(fldV);
n1=size(fldU,1); n2=size(fldU,2);
fldU=reshape(fldU,n1*n2,n3*n4); fldV=reshape(fldV,n1*n2,n3*n4); 

for iy=1:length(mygrid.LATS_MASKS); 

   %get list ofpoints that form a zonal band:
   mmu=convert2array(mygrid.LATS_MASKS(iy).mmu);
   nnu=find(~isnan(mmu)); mmu=mmu(nnu)*ones(1,n3*n4);
   mmv=convert2array(mygrid.LATS_MASKS(iy).mmv);
   nnv=find(~isnan(mmv)); mmv=mmv(nnv)*ones(1,n3*n4);

   %do the area weighed average along this band:
   tmpu=sum(fldU(nnu,:).*mmu,1);
   tmpv=sum(fldV(nnv,:).*mmv,1);

   %store:
   FLD(iy,:)=reshape(sum(tmpu+tmpv,2),[1 n4]);

end; 


1	gforget	1.3	function [FLD]=calc_MeridionalTransport(fldU,fldV,varargin);
2	gforget	1.2	%object: compute net meridional transports of e.g. heat or fresh water
3			%inputs: fldU and fldV are the fields of grid point transport
4			%optional: doScaleWithArea, if 1 then multiply fldU by
5	gforget	1.4	% dyg.*drf and accordingly for fldV.
6	gforget	1.2	% If 0 (default) then it is assumed that those factors
7			% have already been included (e.g. by pkg/diagnostics).
8			%output: FLD is the integrated transport vector (one point per latitude).
9	gforget	1.3	%
10			%notes: mygrid.LATS_MASKS is the set of quasi longitudinal lines along which
11			% transports will integrated, as computed in gcmfaces_lines_zonal
12	gforget	1.1
13			global mygrid;
14
15	gforget	1.3	if nargin==3; doScaleWithArea=varargin{1}; else; doScaleWithArea=0; end;
16	gforget	1.1
17			%initialize output:
18			n3=max(size(fldU.f1,3),1); n4=max(size(fldV.f1,4),1);
19	gforget	1.3	FLD=NaN*squeeze(zeros(length(mygrid.LATS_MASKS),n4));
20	gforget	1.1
21			%prepare fldU/fldV:
22			fldU(isnan(fldU))=0; fldV(isnan(fldV))=0;
23
24			if doScaleWithArea;
25			dxg=mk3D(mygrid.DXG,fldU); dyg=mk3D(mygrid.DYG,fldU); drf=mk3D(mygrid.DRF,fldU);
26			for k4=1:n4;
27	gforget	1.4	fldU(:,:,:,k4)=fldU(:,:,:,k4).dyg.drf;
28			fldV(:,:,:,k4)=fldV(:,:,:,k4).dxg.drf;
29	gforget	1.1	end;
30			end;
31
32			%use array format to speed up computation below:
33			fldU=convert2array(fldU); fldV=convert2array(fldV);
34			n1=size(fldU,1); n2=size(fldU,2);
35			fldU=reshape(fldU,n1n2,n3n4); fldV=reshape(fldV,n1n2,n3n4);
36
37	gforget	1.3	for iy=1:length(mygrid.LATS_MASKS);
38	gforget	1.1
39			%get list ofpoints that form a zonal band:
40	gforget	1.3	mmu=convert2array(mygrid.LATS_MASKS(iy).mmu);
41	gforget	1.1	nnu=find(~isnan(mmu)); mmu=mmu(nnu)ones(1,n3n4);
42	gforget	1.3	mmv=convert2array(mygrid.LATS_MASKS(iy).mmv);
43	gforget	1.1	nnv=find(~isnan(mmv)); mmv=mmv(nnv)ones(1,n3n4);
44
45			%do the area weighed average along this band:
46			tmpu=sum(fldU(nnu,:).*mmu,1);
47			tmpv=sum(fldV(nnv,:).*mmv,1);
48
49			%store:
50			FLD(iy,:)=reshape(sum(tmpu+tmpv,2),[1 n4]);
51
52			end;
53
54