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

itstart = input(' Please enter start iteration : ','s') 
itend = input(' Please enter end iteration : ','s') 


sizeit=size(iterations);
for i=1:sizeit(1)
iter(i)=eval(iterations(i,1:10));
end
nitstart=find(iter==eval(itstart))
nitend=find(iter==eval(itend))

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

sum=zeros(Nx,Ny);
counter=0;

for i=nitstart:nitend
psfilename=(['PS.' iterations((i),1:10) ]) ;
ps=rdmds(psfilename,'b');
sum=sum+ps;
counter=counter+1;
end
meanps=sum/counter;

cmax=max(max(meanps));
cmin=min(min(meanps));
V=[cmin cmax];
figure
caxis('manual')

        title='mean surface pressure';
        imagesc(lat,long,meanps');shading flat;axis image;caxis(V);colorbar('vertical');
        set(gca,'ydir','norm')
        text(50,130,descriptor);text(50,-30,num2str(nitend-nitstart+1));text(80,-30,'files');
        text(0,130,title);
        text(0,-10,'from timestep');text(30,-10,num2str(itstart));
	text(70,-10,'to'); text(80,-10,num2str(itend));