matlab_class/gcmfaces_calc/calc_UEVNfromUXVY.m

function [fldUe,fldVn]=calc_UEVNfromUXVY(fldU,fldV);
%object:    compute Eastward/Northward vectors form X/Y vectors
%inputs:    fldU/fldV are the X/Y vector fields at velocity points
%outputs:   fldUe/fldVn are the Eastward/Northward vectors at tracer points

global mygrid;

%fldU(mygrid.hFacW==0)=NaN; fldV(mygrid.hFacS==0)=NaN;
nr=size(fldU.f1,3); fldU(mygrid.hFacW(:,:,1:nr)==0)=NaN; fldV(mygrid.hFacS(:,:,1:nr)==0)=NaN;

[FLDU,FLDV]=exch_UV(fldU,fldV);

fldUe=fldU; fldVn=fldV;
for iF=1:fldU.nFaces; 
tmp1=FLDU{iF}(1:end-1,:,:); tmp2=FLDU{iF}(2:end,:,:);
fldUe{iF}=reshape(nanmean([tmp1(:) tmp2(:)],2),size(tmp1));
tmp1=FLDV{iF}(:,1:end-1,:); tmp2=FLDV{iF}(:,2:end,:);
fldVn{iF}=reshape(nanmean([tmp1(:) tmp2(:)],2),size(tmp1));
end;

FLDU=fldUe; FLDV=fldVn;
cs=mk3D(mygrid.AngleCS,FLDU); sn=mk3D(mygrid.AngleSN,FLDU);

fldUe=+FLDU.*cs-FLDV.*sn;
fldVn=FLDU.*sn+FLDV.*cs;


1	function [fldUe,fldVn]=calc_UEVNfromUXVY(fldU,fldV);
2	%object: compute Eastward/Northward vectors form X/Y vectors
3	%inputs: fldU/fldV are the X/Y vector fields at velocity points
4	%outputs: fldUe/fldVn are the Eastward/Northward vectors at tracer points
5
6	global mygrid;
7
8	%fldU(mygrid.hFacW==0)=NaN; fldV(mygrid.hFacS==0)=NaN;
9	nr=size(fldU.f1,3); fldU(mygrid.hFacW(:,:,1:nr)==0)=NaN; fldV(mygrid.hFacS(:,:,1:nr)==0)=NaN;
10
11	[FLDU,FLDV]=exch_UV(fldU,fldV);
12
13	fldUe=fldU; fldVn=fldV;
14	for iF=1:fldU.nFaces;
15	tmp1=FLDU{iF}(1:end-1,:,:); tmp2=FLDU{iF}(2:end,:,:);
16	fldUe{iF}=reshape(nanmean([tmp1(:) tmp2(:)],2),size(tmp1));
17	tmp1=FLDV{iF}(:,1:end-1,:); tmp2=FLDV{iF}(:,2:end,:);
18	fldVn{iF}=reshape(nanmean([tmp1(:) tmp2(:)],2),size(tmp1));
19	end;
20
21	FLDU=fldUe; FLDV=fldVn;
22	cs=mk3D(mygrid.AngleCS,FLDU); sn=mk3D(mygrid.AngleSN,FLDU);
23
24	fldUe=+FLDU.cs-FLDV.sn;
25	fldVn=FLDU.sn+FLDV.cs;
26
27