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source: palm/trunk/DOC/app/chapter_3.8.html @ 108

Last change on this file since 108 was 108, checked in by letzel, 17 years ago
  • Improved coupler: evaporation - salinity-flux coupling for humidity = .T.,

avoid MPI hangs when coupled runs terminate, add DOC/app/chapter_3.8;

  • Optional calculation of km and kh from initial TKE e_init;
  • Default initialization of km,kh = 0.00001 for ocean = .T.;
  • Allow data_output_pr= q, wq, w"q", w*q* for humidity = .T.;
  • Bugfix: Rayleigh damping for ocean fixed.
File size: 12.2 KB
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13  <title>PALM chapter 3.8</title>
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43
44
45<h3 style="line-height: 100%;">3.8 Coupled model runs</h3>
46
47
48<p style="line-height: 100%;">Starting from version 3.4
49PALM allows coupled atmosphere-ocean model runs. By analogy with the
50modular structure of PALM, <span style="font-weight: bold;">mrun</span>
51starts the coupled model as two concurrent executables, the atmosphere
52version and&nbsp;the ocean version of PALM.</p>
53
54
55<p style="line-height: 100%;">Currently, the coupler
56is at an experimental stage using a simple MPI2 intercommunicator that
57matches the atmosphere and ocean processors one-to-one. This approach
58has&nbsp;limited flexibility and performance, because it requires
59identical horizontal numerical grids and it uses the same number of
60atmosphere and ocean processors, which does not necessarily guarrantee
61a good load balancing.</p>
62
63
64<p style="line-height: 100%;">The coupler establishes a
65one-way interaction between the
66atmosphere and the ocean. The atmosphere sends its bottom surface
67fluxes
68(temperature, humidity, momentum) to the ocean. The ocean sends its top
69surface temperature to the atmosphere. The atmosphere assumes
70saturation of humidity and zero wind speed at its bottom surface. For
71calculations with <a href="chapter_4.1.html#humidity">humidity</a>
72= .T. the atmospheric evaporation leads to a salinity flux in the ocean
73(see e.g. Steinhorn 1991, JPO 21, p. 1681).</p>
74
75
76<p style="line-height: 100%;">To start a
77coupled&nbsp;model run,
78this must be requested with the <b>mrun</b> option <tt><font style="font-size: 10pt;" size="2">-Y</font>.</tt>
79This tells <span style="font-weight: bold;">mrun</span>
80to start two PALM executables. Coupled runs are only possible in
81parallel mode, which means that the <b>mrun</b> option <tt><font style="font-size: 10pt;" size="2">-K parallel</font></tt>
82must also be set.&nbsp;The <b>mrun</b> call
83for coupled runs has to include the following coupling-related options:
84</p>
85
86
87<ul>
88
89
90 
91  <p style="line-height: 100%;"><tt><font style="font-size: 10pt;" size="2">mrun </font></tt><font style="font-size: 10pt;" size="2">...</font><tt><font style="font-size: 10pt;" size="2"> -K parallel -r
92&ldquo;d3# d3o# </font></tt><font style="font-size: 10pt;" size="2">...</font><tt><font style="font-size: 10pt;" size="2">&rdquo;</font></tt><tt><font style="font-size: 10pt;" size="2"> </font></tt><tt><font style="font-size: 10pt;" size="2">-X </font></tt><font style="font-size: 10pt;" size="2">...</font><tt><font style="font-size: 10pt;" size="2"> -Y</font></tt><tt>.</tt></p>
93
94
95</ul>
96
97
98<p style="line-height: 100%;">The <tt><font style="font-size: 10pt;" size="2">-X </font></tt><font style="font-size: 10pt;" size="2">...</font><tt><font style="font-size: 10pt;" size="2">&nbsp;</font></tt>option
99here specifies the total number of processors assigned to the coupled
100model. Half of them are assigned to each of the two coupled
101executables. Therefore it is advisable to specify an even number
102with&nbsp;<tt><font style="font-size: 10pt;" size="2">-X </font></tt><font style="font-size: 10pt;" size="2">...</font><tt>
103</tt>. Otherwise, in case of an odd total number of processors,
104one processor remains idle.</p>
105
106
107<p style="line-height: 100%;">Each coupled executable has
108its own, unique set of I/O filenames; <a href="chapter_3.4.html#coupled">chapter 3.4</a> gives
109information on file name conventions of coupled runs. The configuration
110file .mrun.config has to be extended for coupled runs. It is
111recommended to duplicate existing file connection identifiers such as
112"d3#", "pr#" etc. using the coupled ocean filenames accordingly. For
113example,&nbsp;the example of the previous chapters could be
114duplicated as follows:</p>
115
116
117<pre style="line-height: 100%;"><a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN</font></a><font style="font-size: 10pt;" size="2"> in:job:npe d3# ~/palm/current_version/JOBS/$fname/INPUT _p3d</font><br><font style="font-size: 10pt;" size="2">PARIN in:job:npe d3f ~/palm/current_version/JOBS/$fname/INPUT _p3df</font><br><a href="chapter_3.4.html#BININ"><font style="font-size: 10pt;" size="2">BININ</font></a><font style="font-size: 10pt;" size="2"> in:loc d3f ~/palm/current_version/JOBS/$fname/OUTPUT _d3d</font><br><font style="font-size: 10pt;" size="2">#</font><br><a href="chapter_3.4.html#BINOUT"><font style="font-size: 10pt;" size="2">BINOUT</font></a><font style="font-size: 10pt;" size="2"> out:loc restart ~/palm/current_version/JOBS/$fname/OUTPUT _d3d<br>#</font><br><a href="chapter_3.4.html#RUN_CONTROL"><font style="font-size: 10pt;" size="2">RUN_CONTROL</font></a><font style="font-size: 10pt;" size="2"> out:loc:tr d3# ~/palm/current_version/JOBS/$fname/MONITORING _rc</font><br><a href="chapter_3.4.html#HEADER"><font style="font-size: 10pt;" size="2">HEADER</font></a><font style="font-size: 10pt;" size="2"> out:loc:tr d3# ~/palm/current_version/JOBS/$fname/MONITORING _header</font><br><a href="chapter_3.4.html#PLOT1D_PAR"><font style="font-size: 10pt;" size="2">PLOT1D_PAR</font></a><font style="font-size: 10pt;" size="2"> out:loc:tr pr# ~/palm/current_version/JOBS/$fname/OUTPUT _pr_par</font><br><a href="chapter_3.4.html#PLOT1D_DATA"><font style="font-size: 10pt;" size="2">PLOT1D_DATA</font></a><font style="font-size: 10pt;" size="2"> out:loc:tr pr# ~/palm/current_version/JOBS/$fname/OUTPUT _pr_in<br>#<br></font><font style="font-size: 10pt;" size="2">PARIN</font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">_O</span> in:job:npe d3<span style="font-weight: bold;">o</span># ~/palm/current_version/JOBS/$fname/INPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">p3d</font><br><font style="font-size: 10pt;" size="2">PARIN<span style="font-weight: bold;">_O</span> in:job:npe d3<span style="font-weight: bold;">o</span>f ~/palm/current_version/JOBS/$fname/INPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">p3df</font><br><font style="font-size: 10pt;" size="2">BININ</font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">_O</span> in:loc d3<span style="font-weight: bold;">o</span>f ~/palm/current_version/JOBS/$fname/OUTPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">d3d</font><br><font style="font-size: 10pt;" size="2">#</font><br><font style="font-size: 10pt;" size="2">BINOUT</font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">_O</span> out:loc restart ~/palm/current_version/JOBS/$fname/OUTPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">d3d</font><br><font style="font-size: 10pt;" size="2">#</font><br><font style="font-size: 10pt;" size="2">RUN_CONTROL<span style="font-weight: bold;">_O</span></font><font style="font-size: 10pt;" size="2"> out:loc:tr d3<span style="font-weight: bold;">o</span># ~/palm/current_version/JOBS/$fname/MONITORING <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">rc</font><br><font style="font-size: 10pt;" size="2">HEADER</font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">_O</span> out:loc:tr d3<span style="font-weight: bold;">o</span># ~/palm/current_version/JOBS/$fname/MONITORING <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">header</font><br><font style="font-size: 10pt;" size="2">PLOT1D_PAR<span style="font-weight: bold;">_O</span></font><font style="font-size: 10pt;" size="2"> out:loc:tr pr<span style="font-weight: bold;">o</span># ~/palm/current_version/JOBS/$fname/OUTPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">pr_par</font><br><font style="font-size: 10pt;" size="2">PLOT1D_DATA</font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">_O</span> out:loc:tr pr<span style="font-weight: bold;">o</span># ~/palm/current_version/JOBS/$fname/OUTPUT <span style="font-weight: bold;">_</span></font><font style="font-size: 10pt;" size="2"><span style="font-weight: bold;">o</span>_</font><font style="font-size: 10pt;" size="2">pr_in</font><br></pre>
118
119
120<p style="line-height: 100%;">The coupled ocean model
121filenames in the first column (e.g.<font style="font-size: 10pt;" size="2"><span style="font-family: mon;"> </span><a href="chapter_3.4.html#PARIN">PARIN_O</a></font>)&nbsp;must
122be specified as given in <a href="chapter_3.4.html#coupled">chapter
1233.4</a>; the file connection identifiers (e.g.&nbsp; <font style="font-size: 10pt;" size="2">d3o#</font>)
124and the file name extension (e.g. &nbsp;<font style="font-size: 10pt;" size="2"><span style="font-weight: bold;"><span style="font-family: mon;"></span></span>_</font><font style="font-size: 10pt;" size="2">o_</font><font style="font-size: 10pt;" size="2">p3d</font>)
125may be changed at the user's discretion.</p>
126
127
128
129
130<p style="line-height: 100%;">The coupler requires the
131following parameters to be equal in both <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
132and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>:
133<a href="chapter_4.1.html#dx">dx</a>, <a href="chapter_4.1.html#dy">dy</a>, <a href="chapter_4.1.html#nx">nx</a>, <a href="chapter_4.1.html#ny">ny</a>, <a href="chapter_4.2.html#dt_coupling">dt_coupling</a>, <a href="chapter_4.2.html#end_time">end_time</a>, <a href="chapter_4.2.html#restart_time">restart_time</a>,
134<a href="chapter_4.2.html#dt_restart">dt_restart</a>. In the coupled atmosphere executable,&nbsp;<a href="chapter_4.2.html#bc_pt_b">bc_pt_b</a> is internally set and does not need to be prescribed; in the coupled ocean executable, <a href="chapter_4.2.html#bc_uv_t">bc_uv_t</a>&nbsp;is internally set ('neumann') and does not need to be prescribed. The coupled ocean parameter file&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a> should include dummy REAL value assignments to both <a href="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</a> and&nbsp;<a href="chapter_4.1.html#top_momentumflux_v">top_momentumflux_v</a> (e.g.&nbsp;top_momentumflux_u = 0.0, top_momentumflux_v = 0.0) to enable the momentum flux coupling.</p>
135<p style="line-height: 100%;">The coupling interval  <a href="chapter_4.2.html#dt_coupling">dt_coupling</a> must be explicity set. In order to ensure synchronous coupling throughout the simulation, <a href="chapter_4.2.html#dt_coupling">dt_coupling</a> should be chosen larger than
136<a href="chapter_4.2.html#dt_max">dt_max</a>.</p>
137<hr>
138<p style="line-height: 100%;"><br>
139
140
141<font color="#000080"><font color="#000080"><a href="chapter_3.7.html"><font color="#000080"><img style="border: 2px solid ; width: 32px; height: 32px;" alt="" src="left.gif" name="Grafik1"></font></a><a href="index.html"><font color="#000080"><img src="up.gif" name="Grafik2" align="bottom" border="2" height="32" width="32"></font></a><a href="chapter_4.0.html"><font color="#000080"><img src="right.gif" name="Grafik3" align="bottom" border="2" height="32" width="32"></font></a></font></font></p>
142
143
144<p style="line-height: 100%;"><i>Last
145change:&nbsp;</i> ++</p>
146
147
148</body>
149</html>
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