%** this script produces maps of sea level pressure 
% 
% uses data in globalclimatology.mat 
% slp       long-term monthly mean sea level pressure in millibars
%           gridded to 2.5 degrees, January to December [73 144 12]
%           derived from 1968 to 1996 data, NCEP/NCAR Reanalysis
% slplat    grid lattitudes
% slplon    grid longitudes

load globalclimatology.mat

load coast                          % Matlab native file

%* SET map month and figure numbers
mapS=6;     % select index number of month to plot
FN=50;      % starting figure number
 
%* ranges for color scales
Csmin=min(min(min(slp)));                 
Csmax=max(max(max(slp)));

%* map plot window
wind=[min(slplon) max(slplon) min(slplat) max(slplat)];  

 
 
%********
% sea level pressure flat map for specified month
%********

data=slp(:,:,mapS);

figure(FN)                      % open figure window
clf
caxis([Csmin Csmax])            % set color range for this plot
axis equal
axis(wind)                      % define axes for this plot
hold on
pcolor(slplon, slplat, data)      % simple Plate Carree projection
shading flat
xlabel('longitude')
ylabel('latitude')
title('mean monthly sea level pressure (mb)')
text(190, 90, int2str(mapS))    % add month number for reference
colorbar horiz
hold on
plot(long, lat, 'k-')



 
%********
% sea level pressure December-June difference
%********

data=slp(:,:,12)-slp(:,:,6);
Cdmin=floor(min(min(data)));
Cdmax=abs(Cdmin);

figure(FN+5)
clf
caxis([Cdmin Cdmax])            % set color range for this plot
axis equal
axis(wind)
hold on
pcolor(slplon, slplat, data)
shading flat
xlabel('longitude')
ylabel('latitude')
title('December - June sea level pressure (mb)')
colorbar horiz
hold on
plot(long, lat, 'k-')