ecom_depaveuv

 ECOM_DEPAVEUV computes the depth-averaged value of velocity at
        a given time step of a ECOM model run.

  Usage:  [wmean,x,y]=ecom_depaveuv(cdf,[tstep],[bounds])

  where:  cdf = ecomsi.cdf run
          var = variable to depth-average
          tstep = time step (default = 1)
          bounds = [imin imax jmin jmax] limits
                   (default = [1 nx 1 ny])

          wmean = depth-averaged velocity
          x = x locations of the returned array wmean
          y = y locations of the returned array wmean

  Example 1:  [wmean,x,y]=ecom_depave('ecomsi.cdf');

       computes the depth-averaged velocity at the 1st time step
       over the entire domain.

  Example 2:  [wmean,x,y]=ecom_depave('ecomsi.cdf',10);

       computes the depth-averaged velocity at the 10th time step
       over the entire domain.

  Example 3:  [wmean,x,y]=ecom_depave('ecomsi.cdf',10,[10 30 30 50]);

       computes the depth-averaged velocity at the 10th time step
       in the subdomain defined by i=10:30 and j=30:50.

0001 function [wmean,x,y]=ecom_depaveuv(cdfin,tind,bounds)
0002 % ECOM_DEPAVEUV computes the depth-averaged value of velocity at
0003 %        a given time step of a ECOM model run.
0004 %
0005 %  Usage:  [wmean,x,y]=ecom_depaveuv(cdf,[tstep],[bounds])
0006 %
0007 %  where:  cdf = ecomsi.cdf run
0008 %          var = variable to depth-average
0009 %          tstep = time step (default = 1)
0010 %          bounds = [imin imax jmin jmax] limits
0011 %                   (default = [1 nx 1 ny])
0012 %
0013 %          wmean = depth-averaged velocity
0014 %          x = x locations of the returned array wmean
0015 %          y = y locations of the returned array wmean
0016 %
0017 %  Example 1:  [wmean,x,y]=ecom_depave('ecomsi.cdf');
0018 %
0019 %       computes the depth-averaged velocity at the 1st time step
0020 %       over the entire domain.
0021 %
0022 %  Example 2:  [wmean,x,y]=ecom_depave('ecomsi.cdf',10);
0023 %
0024 %       computes the depth-averaged velocity at the 10th time step
0025 %       over the entire domain.
0026 %
0027 %  Example 3:  [wmean,x,y]=ecom_depave('ecomsi.cdf',10,[10 30 30 50]);
0028 %
0029 %       computes the depth-averaged velocity at the 10th time step
0030 %       in the subdomain defined by i=10:30 and j=30:50.
0031 %
0032 %
0033 if(nargin==1),
0034   tind=1;
0035 end
0036 cdfid1=mexcdf('open',cdfin,'nowrite');
0037 if(cdfid1==-1),
0038   disp(['file ' cdf ' not found'])
0039   return
0040 end
0041 [nam,nxr]=mexcdf('diminq',cdfid1,'xpos');
0042 [nam,nyr]=mexcdf('diminq',cdfid1,'ypos');
0043 [nam,nz]=mexcdf('diminq',cdfid1,'zpos');
0044 if(nargin< 3),
0045   ix=0;
0046   iy=0;
0047   nx=nxr;
0048   ny=nyr;
0049 else
0050   if(bounds(2)>nxr|bounds(4)>nyr),disp('out of bounds'),return,end
0051   ix=bounds(1)-1;
0052   nx=bounds(2)-bounds(1)+1;
0053   iy=bounds(3)-1;
0054   ny=bounds(4)-bounds(3)+1;
0055 end
0056 depth=mexcdf('varget',cdfid1,'depth',[iy ix],[ny nx]);
0057 x=mexcdf('varget',cdfid1,'x',[iy ix],[ny nx]);
0058 y=mexcdf('varget',cdfid1,'y',[iy ix],[ny nx]);
0059 ang=mexcdf('varget',cdfid1,'ang',[iy ix],[ny nx]);
0060 sigma=mexcdf('varget',cdfid1,'sigma',[0],[nz]);
0061 dsigma=-diff(sigma);
0062 h1=mexcdf('varget',cdfid1,'h1',[iy ix],[ny nx]);
0063 h2=mexcdf('varget',cdfid1,'h2',[iy ix],[ny nx]);
0064 area=h1.*h2;
0065 wmean=zeros(nx,ny);
0066 for j=[1:nz-1],
0067   u=mexcdf('varget',cdfid1,'u',[tind-1 j-1 iy ix],[1 1 ny nx],1); %get a layer
0068   v=mexcdf('varget',cdfid1,'v',[tind-1 j-1 iy ix],[1 1 ny nx],1); %get a layer
0069   u=u(1:nx-1,:)+.5*diff(u);
0070   u(nx,:)=u(nx-1,:);
0071   v=v(:,1:ny-1)+.5*diff(v')';
0072   v(:,ny)=v(:,ny-1);
0073   w=u+sqrt(-1)*v;
0074   wmean=wmean+dsigma(j)*w;  %multiply layer values by normalized layer thickness
0075 end
0076 dind=find(depth==-99999 | depth==0);
0077 wmean(dind)=wmean(dind)*NaN;
0078 wmean=wmean.*exp(sqrt(-1)*ang);
0079 mexcdf('close',cdfid1);