-
Notifications
You must be signed in to change notification settings - Fork 0
/
gsw_demo.asv
176 lines (172 loc) · 9.6 KB
/
gsw_demo.asv
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
gsw_data = 'gsw_data_v3_0.mat';
gsw_data_file = which(gsw_data);
load (gsw_data_file,'gsw_demo_data');
clear gsw_data gsw_data_file
%test if Java Virtual Machine is running
try
JavaVirtMach = system_dependent('useJava','jvm');
catch
% assume no Java Virtual Machine
JavaVirtMach = 0;
end
fprintf(1,'Welcome the Gibbs Seawater (GSW) Oceanographic Toolbox (version 3.05). \n');
pause(3)
fprintf(1,'This is a short demonstration of some of the features of the \n');
fprintf(1,'GSW Oceanographic toolbox. \n');
fprintf(1,' \n');
fprintf(1,'The most important functions are the first two functions. \n');
fprintf(1,' \n');
fprintf(1,'The following vertical profiles, from the North Pacific, are of \n');
fprintf(1,'Practical Salinity, SP, and in-situ temperature, t, as a function \n');
fprintf(1,'of pressure, p, \n');
pause(6)
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'SP = [',gsw_demo_data.SP([1,22,29:4:45],1)',']');
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'t = [',gsw_demo_data.t([1,22,29:4:45],1)',']');
fprintf(1,'%s %7.0f %7.0f %7.0f %7.0f %7.0f %7.0f %7.0f %s \n' ,'p = [',gsw_demo_data.p([1,22,29:4:45],1)',']');
fprintf(1,'Note that, we have shown only seven bottles from the full vertical profile. \n');
fprintf(1,' \n');
pause(6)
fprintf(1,'The first step under TEOS-10 is to convert Practical Salinity, SP, \n');
fprintf(1,'into Absolute Salinity, SA. This is done with the function "gsw_SA_from_SP" \n');
pause(6)
fprintf(1,'SA = gsw_SA_from_SP(SP,p,long,lat) \n');
gsw_demo_data.SA = gsw_SA_from_SP(gsw_demo_data.SP,gsw_demo_data.p,gsw_demo_data.long,gsw_demo_data.lat);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'SA = [',gsw_demo_data.SA([1,22,29:4:45],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'The second step is to convert in-situ temperature, t, into \n');
fprintf(1,'Conservative Temperature, CT, using the function \n');
fprintf(1,'"gsw_CT_from_t", \n');
pause(6)
fprintf(1,'CT = gsw_CT_from_t(SA,t,p) \n');
gsw_demo_data.CT = gsw_CT_from_t(gsw_demo_data.SA,gsw_demo_data.t,gsw_demo_data.p);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'CT = [',gsw_demo_data.CT([1,22,29:4:45],1)',']');
fprintf(1,' \n');
fprintf(1,'At this point the data has been converted into SA and CT, which are \n');
fprintf(1,'the TEOS-10 salinity and temperature variables. With these variables it \n');
fprintf(1,'is possible to compute the complete range of water column properties. \n');
fprintf(1,' \n');
pause(6)
fprintf(1,'The first property to be demonstrated is density (rho) as a function \n');
fprintf(1,'of SA and CT. This is computed by using the function "gsw_rho". \n');
fprintf(1,'The use of a single algorithm for seawater density (the 75-term computationally \n');
fprintf(1,'efficient expression) ensures consistency between ocean modelling, observational \n');
fprintf(1,'oceanography, and theoretical studies. Note that this is not been the case to \n');
fprintf(1,'date under EOS-80. \n');
fprintf(1,'rho = gsw_rho(SA,CT,p) \n');
gsw_demo_data.rho = gsw_rho(gsw_demo_data.SA,gsw_demo_data.CT,gsw_demo_data.p);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'rho = [',gsw_demo_data.rho([1,22,29:4:45],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'Using this same programme, gsw_rho, it is possible to compute potential \n');
fprintf(1,'density by replacing the in-situ pressure, p with the reference pressure, \n');
fprintf(1,'p_ref. \n');
fprintf(1,' \n');
pause(2)
fprintf(1,'An example. We have set p_ref to be 2000 dbar, thus we have the potential \n');
fprintf(1,'density referenced to 2000 dbars. \n');
fprintf(1,'pot_rho_2 = gsw_rho(SA,CT,p_ref) \n');
gsw_demo_data.pot_rho_2 = gsw_rho(gsw_demo_data.SA,gsw_demo_data.CT,gsw_demo_data.p_ref);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'pot_rho_2 = [',gsw_demo_data.pot_rho_2([1,22,29:4:45],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'The potential density anomaly can be obtained by using the function \n');
fprintf(1,'"gsw_rho" - 1000 kg/m^3. \n');
fprintf(1,'Two examples of this are sigma_0 and sigma_2 which can be calculated \n');
fprintf(1,'as follows \n');
fprintf(1,'sigma_0 = gsw_rho(SA,CT,0) - 1000 \n');
gsw_demo_data.sigma_0 = gsw_rho(gsw_demo_data.SA,gsw_demo_data.CT,0) -1000;
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'sigma_0 = [',gsw_demo_data.sigma_0([1,22,29:4:45],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'sigma_2 = gsw_rho(SA,CT,2000) - 1000 \n');
gsw_demo_data.sigma_2 = gsw_rho(gsw_demo_data.SA,gsw_demo_data.CT,2000) - 1000;
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'sigma_2 = [',gsw_demo_data.sigma_2([1,22,29:4:45],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'However, there are alternatives to the last two calls, we have provided \n');
fprintf(1,'some short-cuts for the standard oceaongraphic variables as functions of \n');
fprintf(1,'SA and CT, the alternative short-cuts to the above two calls are: \n');
fprintf(1,'sigma_0 = gsw_sigma0(SA,CT) \n');
fprintf(1,' and \n');
fprintf(1,'sigma_2 = gsw_sigma2(SA,CT) \n');
fprintf(1,' \n');
pause(6)
fprintf(1,'Calculating the Conservative Temperature at which seawater freezes is \n');
fprintf(1,'done with the function \n');
fprintf(1,'"gsw_CT_freezing_poly" \n');
fprintf(1,'This programme allows the user to choose the amount of air which the water \n');
fprintf(1,'contains. When saturation_fraction is 0 the seawater contains no air, and \n');
fprintf(1,'when saturation_fraction is 1 the seawater is completely saturated with air. \n');
fprintf(1,'The default setting is to have the seawater aior free. \n');
fprintf(1,'CT_freezing = gsw_CT_freezing_poly(SA,p) \n');
gsw_demo_data.CT_freezing = gsw_CT_freezing(gsw_demo_data.SA,gsw_demo_data.p);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'CT_freezing = [',gsw_demo_data.CT_freezing([1,22,29:4:45],1)',']');
fprintf(1,' \n');
fprintf(1,'Press enter to continue. \n');
pause
fprintf(1,'We now plot the profile on the Absolute Salinity - Conservative Temperature diagram \n');
fprintf(1,'This can be done by calling "gsw_SA_CT_plot". This function plots the \n');
fprintf(1,'Absolute Salinity and Conservative Temperature profile data on a SA-CT diagram \n');
fprintf(1,'with user definied potential density contours and the Conservative Temperature \n');
fprintf(1,'freezing line at p of 0 dbar. The potential density anomaly contours are \n');
fprintf(1,'referenced to user supplied depth are also included. In this example we have \n');
fprintf(1,'set the reference pressure to be 2000 dbar. \n');
fprintf(1,'note that this plotting function relies on the functions \n');
fprintf(1,'"gsw_rho" and "gsw_CT_freezing_poly" \n');
fprintf(1,' \n');
fprintf(1,'p_ref = 2000 \n');
fprintf(1,'gsw_SA_CT_plot(SA,CT,p_ref,''\\itS\\rm_A - \\Theta plot'') \n');
pause(6)
if JavaVirtMach == 1
try
fig1 = figure;
set(fig1,'pos','default','menubar','none','numbertitle','off', ...
'name','GSW demo')
hax1 = axes('pos',[0 0 1 1],'parent',fig1);
axis(hax1,'off');
str1(1) = {'An \it{S}\rm_A - {\Theta} diagram will soon appear.'};
str1(2) = {' '};
str1(3) = {'When you have finished studying the plot,'};
str1(4) = {'minimise or close the window '};
str1(5) = {'and press enter to continue.'};
text(.5,.6,str1,'parent',hax1,'horizontalalignment','center','fontsize',18)
pause(6)
clf(fig1)
set(fig1,'pos','default','menubar','none','numbertitle','off', ...
'name','GSW demo - An example SA_CT diagram')
gsw_SA_CT_plot(gsw_demo_data.SA(:,1),gsw_demo_data.CT(:,1),gsw_demo_data.p_ref,[32.5:0.5:38],'\itS\rm_A - \Theta diagram');
fprintf(1,'When you have finished studying the plot press enter to continue\n');
pause
catch
fprintf(1,' \n');
fprintf(1,'It appears that you are running MATLAB without the Java Virtual Machine, \n');
fprintf(1,'so we can not show the resulting figure. \n');
end
else
fprintf(1,' \n');
fprintf(1,'It appears that you are running MATLAB without the Java Virtual Machine, \n');
fprintf(1,'so we can not show the resulting figure. \n');
end
fprintf(1,' \n');
pause(2)
fprintf(1,'The bouyancy (Brunt Vasaila) frequency squared (N^2) at the mid point \n');
fprintf(1,'pressure (p_mid) between the "bottles" can be obtained by using the \n');
fprintf(1,'function "gsw_Nsquared" \n');
fprintf(1,'[N2, p_mid] = gsw_Nsquared(SA,CT,p) \n');
[gsw_demo_data.N2, gsw_demo_data.p_mid] = gsw_Nsquared(gsw_demo_data.SA,gsw_demo_data.CT,gsw_demo_data.p);
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'N2 = [',1e5*gsw_demo_data.N2([1,22,29:4:44],1)','] (*1e-5)');
fprintf(1,' \n');
fprintf(1,'%s %7.2f %7.2f %7.2f %7.2f %7.2f %7.2f %s \n' ,'p_mid = [',gsw_demo_data.p_mid([1,22,29:4:44],1)',']');
fprintf(1,' \n');
pause(6)
fprintf(1,'The dynamic height anomaly, commmonly shortened to "dynamic height", can be \n');
fprintf(1,'calculated with the function "gsw_geo_strf_dyn_height". In this function \n');
fprintf(1,'the user defines the the reference pressure that they want the dymanic height \n');
fprintf(1,'relative to. In this example we set p_ref to be 2000 dbar. \n');
gsw_demo_data.geo_strf_dyn_height = gsw_geo_strf_dyn_height(gsw_demo_data.SA,gsw_demo_data.CT,gsw_demo_data.p,gsw_demo_data.p_ref);
fprintf(1,'geo_strf_dyn_height = gsw_geo_strf_dyn_height(SA,CT,p,p_ref) \n');
fprintf(1,'%s %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %7.4f %s \n' ,'geo_strf_dyn_height = [',gsw_demo_data.geo_strf_dyn_height([1,22,29:4:45],1)',']');
pause(4)
fprintf(1,'The end. \n');
clear gsw_demo_data JavaVirtMach