clear 
clear path 

global Nx Ny Nz
global lat long dz dm mdep
global delt_su su_its t_su delt
global descriptor this_path
global f deltaf Q beta r_expt r_heat H
global time rots it
global g Cp rho_bar alpha
global u v t w
global iterations


param_file_name =   ...
   input(' Please enter the name of the m-file with the parameters for this run : ','s') ;
feval(param_file_name) ;

iterations

it = input(' Please enter iteration : ','s') 

path   = this_path 
cmdstr=['cd ' path ];
eval(cmdstr);
path=pwd

ufilename=(['uVel.' it ]);
vfilename=(['vVel.' it ]);
tfilename=(['theta.' it ]);
u=rdmeta(ufilename,'b');
v=rdmeta(vfilename,'b');
t=rdmeta(tfilename,'b');

w=zeros(Nx,Ny,Nz+1);
dx=dm;
dy=dm;

for k=Nz:-1:1,
 w(1:Nx-1,1:Ny-1,k)= w(1:Nx-1,1:Ny-1,k+1)...
                    -u(2:Nx,1:Ny-1,k)*dz(k)/dx +u(1:Nx-1,1:Ny-1,k)*dz(k)/dx ...
                    -v(1:Nx-1,2:Ny,k)*dz(k)/dy +v(1:Nx-1,1:Ny-1,k)*dz(k)/dy ;
end