GLOBAL OCEAN CLIMATOLOGICAL DATA SET
( part1: GDEMV )

INTRODUCTION
GDEM is the global climatolgical T, S, and sound speed data set (binary)
built up from MOODS. The support programs are written in the C language.
The executable file get_gdem is used to get the GDEM data with a
ASCII column by colmun output file. Most column data are on the standard
35 levels
(0, 10, 20, 30, 50, 75, 100, 125, 150, 200, 250, 300, 400,
500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400,
1500, 1750, 2000, 2500, 3000, 4000, 5000, 6000, 7000,
8000, 9000, 9999).
with the deepest data at the ocean bottom.

For the seasonal data the seasons are defined as follows:

Indian Ocean = lat < 0.0 , lon > 20.0 , lon < 145.0
Winter = mid-October through February
Spring = March through mid-May
Summer = mid-May through mid-July
Autumn = mid-July through mid-October

Arctic Ocean = lat > 65.0
Winter = November through March
Spring = April
Summer = May through September
Autumn = October

All other areas
Winter = January through March
Spring = April through June
Summer = July through September
Autumn = October through December


Rather than actual values of temperature and salinity, GDEM contains
coefficients for equations describing vertical distribution.

PROCEDURE
(1) The UNIX executable file for retrieving GDEMV data is 'get_gdem'.

% get_gdem
SOFTWARE VERSION - OAML GDEMV Reader 1.21 - 10/30/97
INDEX FILE VERSION - OAML GDEMV Version 2.3 - Mon Sep 27 16:44:45 1999
DATA FILE VERSION - OAML GDEMV Version 2.3 - Mon Sep 27 16:44:45 1999

input main output file name: NA

select output variables:
1 - temp only
2 - temp & salt
3 - temp, salt & sound speed 2

input the west and east longitude and resulotion(min): -85 -50 60

input the south and north latitude and resulotion(min): 20 45 60

input the start and end mouth (1-12) or season (13-16): 5 5


%

(2) View your results using UNIX command 'more':
(or other graphics edit)

% more NA.May

'enter key' for adding one line, 'space key' for adding one page,
and 'q key' for quitting.

(3) Use Matlab scripts to view the data:

open Matlab than make the path:
% matlab
% mappath;

(a) get temperature data from regional gdem data file: NA.May

>> [data,botdat,h,lon,lat,levs,sdlev]=getgdemdata('NA.May','temp');
where: data: standard level 3-D temp data without the bottom (34,my,mx)
botdat: 2-D bottom temp data (my,mx)
h: 2-D depth data (>0 under water)
lon,lat: 1-D longitude & latitude
levs: 2-D column data level (my,mx)
sdlev: 1-D standard level (36)
input: first: filename (must)
second: variable name (or number):
'temp' (1) 'salt' (2) 'soundspeed' (3)

(b) contour plot of tempearture field at 200m depth.

>> [lonn,latt,topo]=opmcmap(-85,-50,20,45,'depth',200);
>> if(lon(1)<lonn(1)-300), lon=lon+360; end
>> if(lon(1)>lonn(1)+300), lon=lon-360; end
>> t200=data(10,:,:); [my,mx]=size(h);
>> t2d=reshape(t200,my,mx);
>> [cs,hh]=contour(lon,lat,t2d);
>> clabel(cs,hh,'manual');
>> title('Temperature (^oc) at 200M level');


(c) pcolor plot of sea surface temperature.

>> [c,cf,cf2,xlm,ylm]=mcmapc(lonn,latt,topo);
>> opfg(-85,-50,20,45);
>> plot(c(1,:),c(2,:));
>> if(lon(1)<lonn(1)-300), lon=lon+360; end
>> if(lon(1)>lonn(1)+300), lon=lon-360; end
>> t0=data(1,:,:); [my,mx]=size(botdat);
>> tsf=reshape(t0,my,mx);
>> pcolor(lon,lat,tsf);
>> shading interp;
>> drawmap(c,cf,cf2);
>> spgrid(lonn(1),lonn(end),latt(1),latt(end));
>> wrtxylab(lonn(1),lonn(end),latt(1),latt(end));
>> colorbar('horizontal');
>> title('Sea Surface Temperature (^oc)');


ASSIGNMENT

1. get salinity data.
2. Make one plot:
top half: contour plot of salinity at 100 m depth.
bottom half: pcolor plot of sea surface silinity.

save the figures as jpeg files