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3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
4  <head>
5    <title>div.pro (SAXO Documentation Assistant)</title>
6  </head>
7
8  <body text="#000000" bgcolor="#FFFFFF">
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[168]48<a href="curl.html"><img src="./../prev.gif" border="0" alt="Previous"></a></td>
[163]49    <td width="80%" align="center" valign="center">
[168]50<font size=-1><i>SAXO Documentation Assistant</i>: <a href="./../home.html">Overview</a></font></td>
[163]51    <td width="10%" align="right">
[168]52<a href="grad.html"><img src="./../next.gif" border="0" alt="Next"></a></td>
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54</table>
55
56
[168]57    <h1><font size="-2">Computation/</font></h1>
[163]58    <h2>div.pro</h2>
59
60    <dl>
61    </dl>
62
63   
[321]64 compute the horizontal divergence of a vectors field located on Arakawa C-grid.
[163]65
66
67   
68
69     
70      <a name="#_div"></a>
71
72      <h2>div  <font size="-1" color="#006633">
73 Calculation
74</font></h2>
75
[321]76      <p><font face="Courier"><i>result = </i>div(<i><a href="#_div_keyword_uu">uu</a>, <a href="#_div_keyword_vv">vv</a></i>, <a href="#_div_keyword_DIREC">DIREC</a>=<i>scalar string</i>, <a href="#_div_keyword_MILLION">MILLION</a>=<i>scalar: 0 or 1</i>, <a href="#_div_keyword__EXTRA">_EXTRA</a>=<i>_EXTRA</i>)</font></p>
[163]77
78   
79
80
[242]81    <h3>Return value</h3>
[321]82 the divergence of the input data (with the same size) located at T
83point (see restrictions).
[163]84
85
86   
87    <h3>Parameters</h3>
88   
89
90    <a name="#_div_keyword_uu"></a>
91    <h4>uu&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
92     
93     
94     
95     
96     
97     
98     
99     
100    </h4>
101
[234]102   
[321]103 Matrix representing the zonal coordinates (at U point) of a field of vectors
[290]104 A 2D (xy), 3D (xyz or yt) or a structure readable by <a href="..//ToBeReviewed/LECTURE/litchamp.html">litchamp</a> and containing
[242]105 a 2D (xy), 3D (xyz or yt) array (4D case is not coded yet).
[234]106 note that the dimension of the array must suit the domain dimension.
[163]107
108   
109
110    <a name="#_div_keyword_vv"></a>
111    <h4>vv&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
112     
113     
114     
115     
116     
117     
118     
119     
120    </h4>
121
[234]122   
[321]123 Matrix representing the meridional coordinates (at V point) of a field of vectors
[290]124 A 2D (xy), 3D (xyz or yt) or a structure readable by <a href="..//ToBeReviewed/LECTURE/litchamp.html">litchamp</a> and containing
[242]125 a 2D (xy), 3D (xyz or yt) array (4D case is not coded yet).
[234]126 note that the dimension of the array must suit the domain dimension.
[163]127
128   
129   
130
131   
[168]132    <h3>Keywords</h3>
[163]133
134   
[168]135    <a name="#_div_keyword_DIREC"></a>
136    <h4>DIREC&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
137     
138     
139     
140     
141     
142      <font size="-1" color="#006633">type:</font> <font size="-1" color="#006633"><i>scalar string</i></font>
143     
144     
145    </h4>
146
147   
[242]148 Use if you want to call <a href="..//ToBeReviewed/CALCULS/moyenne.html">moyenne</a> or
149 <a href="..//ToBeReviewed/CALCULS/grossemoyenne.html">grossemoyenne</a> after the div computation
[168]150 (stupid ?) with a mean done in the DIREC direction
151
152   
[321]153    <a name="#_div_keyword_MILLION"></a>
154    <h4>MILLION&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
155     
156     
157     
158     
159     
160      <font size="-1" color="#006633">type:</font> <font size="-1" color="#006633"><i>scalar: 0 or 1</i></font>
161      <font size="-1" color="#006633">default:</font> <font size="-1" color="#006633"><i>0</i></font>
162     
163    </h4>
164
[168]165   
[321]166 Activate to multiply returned array by 1.e6
167 
168   
169    <a name="#_div_keyword__EXTRA"></a>
170    <h4>_EXTRA&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
171     
172     
173     
174     
175     
176     
177     
178     
179    </h4>
[168]180
[321]181   
182 Used to declare that this routine accepts inherited keywords
183
184   
185   
186
[234]187    <h3>Examples</h3><pre>
[168]188
[402]189   IDL> @tst_initorca2
190   IDL> plt, div(dist(jpi,jpj), dist(jpi,jpj))
191
[234]192    </pre><h3>Version history</h3>
[163]193   
194    <h4>Version</h4>
[402]195 $Id: div.pro 378 2008-08-12 12:35:46Z pinsard $
[163]196
197    <h4>History</h4>
[168]198 Guillaume Roullet (grlod@ipsl.jussieu.fr): creation; spring 1998
199 Sebastien Masson (smasson@lodyc.jussieu.fr)
200 adaptation to work with a reduce domain; 12/1/2000
[163]201
202   
203
204    <h3>Known issues</h3>
205   
206   
[234]207    <h4>Todo items</h4>
[242]208 code the 4D case
209
[163]210    <h4>Restrictions</h4>
211
[234]212 - Works only for Arakawa C-grid.
[168]213 - UU must be on U grid, VV must be on V grid
[242]214 - 4D case is not coded yet
[168]215 - the common variable jpt is used to differ xyz (jpt=1) and xyt (jpt=1) cases.
[234]216 - U and V arrays are cut in the same geographic domain. Because of the shift between
217   T, U, V and F grids, it is possible that these two arrays do not have the same
218   size and refer to different indexes. In this case, arrays are re-cut on
[242]219   common indexes. To avoid these re-cuts, use the keyword /memeindice in
220 <a href="..//ToBeReviewed/GRILLE/domdef.html">domdef</a>
[168]221 - When computing the divergence, we update, vargrid, varname, varunits and the
222   grid position parameters (firstxt, lastxt, nxt, firstyt, lastyt, nyt).
[234]223 - points that cannot be computed (domain boundaries, coastline) are set to NaN
[163]224
225
226    <h3>Other attributes</h3>
227   
228   
229    <h4>Uses routines</h4>
[402]230 <a href="..//Commons/cm_4cal.html">cm_4cal</a>
231 <a href="..//Commons/cm_4data.html">cm_4data</a>
232 <a href="..//Commons/cm_4mesh.html">cm_4mesh</a>
[163]233
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237
238    <font size="-3"><p>&nbsp;</p></font>
239    <hr size="1" color="#CCCCCC"/>
240     
241
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243
[187]244    <p><font color="gray" size="-3">&nbsp;&nbsp;Produced by IDLdoc 2.0.</font></p>
[163]245
246  </body>
[249]247</html>
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