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5  <title>PALM chapter 4.4</title><meta content="StarOffice 7  (Win32)" name="GENERATOR">
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17<h3 style="line-height: 100%;">4.4 Example of a minimum parameter set</h3>
18<p style="line-height: 100%;">In this chapter a brief, simple and
19complete parameter set is described, which can be used to carry out a
20model run. The presented example is available via <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/INSTALL/example_p3d">example
21file</a> and can be used (together with the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/INSTALL/.mrun.config">configuration
22file</a> described in <a href="chapter_3.2.html">chapter
233.2)</a> for the execution of a simple model run. </p>
24<p style="line-height: 100%;">This run simulates a quasi-stationary,
25convective, atmospheric boundary layer with&nbsp; <font color="#000000">zero
26mean horizontal
27wind.</font> For evaluation purposes, cross sections and horizontally averaged vertical
28profiles of typical boundary layer variables
29are output at the end of the run. The run shall be carried out in
30batch mode on the IBM Regatta "hanni" of the HLRN.</p>
31<p style="line-height: 100%;">The parameter file necessary to carry
32out a run must be provided to the model as an input file under the
33local name <a href="chapter_3.4.html#PARIN">PARIN</a>
34and has the following contents:</p>
35<pre style="line-height: 100%;">&amp;inipar  <a href="chapter_4.1.html#nx">nx</a> = <span style="font-style: italic;">39</span>, <a href="chapter_4.1.html#ny">ny</a> = <span style="font-style: italic;">39</span>, <a href="chapter_4.1.html#nz">nz</a> = <span style="font-style: italic;">40</span>,<br>         <a href="chapter_4.1.html#dx">dx</a> = <span style="font-style: italic;">50.0</span>, <a href="chapter_4.1.html#dy">dy</a> = <span style="font-style: italic;">50.0</span>, <a href="chapter_4.1.html#dz">dz</a> = <span style="font-style: italic;">50.0</span>,<br>         <a href="chapter_4.1.html#dz_stretch_level">dz_stretch_level</a> = <span style="font-style: italic;">1200.0</span>,<br>         <a href="chapter_4.1.html#fft_method">fft_method</a> = <span style="font-style: italic;">'temperton-algorithm'</span>,<br>         <a href="chapter_4.1.html#initializing_actions">initializing_actions</a> = <span style="font-style: italic;">'set_constant_profiles'</span>,<br>         <a href="chapter_4.1.html#ug_surface">ug_surface</a> = <span style="font-style: italic;">0.0</span>, <a href="chapter_4.1.html#vg_surface">vg_surface</a> = <span style="font-style: italic;">0.0</span>,<br>         <a href="chapter_4.1.html#pt_vertical_gradient">pt_vertical_gradient</a> = <span style="font-style: italic;">0.0</span>, <span style="font-style: italic;">1.0</span>,<br>         <a href="chapter_4.1.html#pt_vertical_gradient_level">pt_vertical_gradient_level</a> = <span style="font-style: italic;">0.0</span>, <span style="font-style: italic;">800.0</span>,<br>         <a href="chapter_4.1.html#surface_heatflux">surface_heatflux</a> = <span style="font-style: italic;">0.1</span>, <a href="chapter_4.1.html#bc_pt_b">bc_pt_b</a> = <span style="font-style: italic;">'neumann'</span>,/<br><br>&amp;d3par   <a href="chapter_4.2.html#end_time">end_time</a> = <span style="font-style: italic;">3600.0</span>,<br>         <a href="chapter_4.2.html#create_disturbances">create_disturbances</a> = <span style="font-style: italic;">.T.</span>,<br>         <a href="chapter_4.2.html#dt_disturb">dt_disturb</a> = <span style="font-style: italic;">150.0</span>, <a href="chapter_4.2.html#disturbance_energy_limit">disturbance_energy_limit</a> = <span style="font-style: italic;">0.01</span>,<br>         <a href="chapter_4.2.html#dt_run_control">dt_run_control</a> = <span style="font-style: italic;">0.0</span>,<br>         <a href="chapter_4.2.html#data_output">data_output</a> = <span style="font-style: italic;">'w_xy'</span>, <span style="font-style: italic;">'w_xz'</span>, <span style="font-style: italic;">'w_xz_av'</span>, <span style="font-style: italic;">'pt_xy'</span>, <span style="font-style: italic;">'pt_xz'</span>,<br>         <a href="chapter_4.2.html#dt_data_output">dt_data_output</a> = <span style="font-style: italic;">900.0</span>,<br>         <a href="chapter_4.2.html#dt_data_output_av">dt_data_output_av</a> = <span style="font-style: italic;">1800.0</span>,<br>         <a href="chapter_4.2.html#averaging_interval">averaging_interval</a> = <span style="font-style: italic;">900.0</span>,<br>         <a href="chapter_4.2.html#dt_averaging_input">dt_averaging_input</a> = <span style="font-style: italic;">10.0</span>,<br>         <a href="chapter_4.2.html#section_xy">section_xy</a> = <span style="font-style: italic;">2</span>, <span style="font-style: italic;">10</span>, <a href="chapter_4.2.html#section_xz">section_xz</a> = <span style="font-style: italic;">20</span>,<br>         <a href="chapter_4.2.html#data_output_2d_on_each_pe">data_output_2d_on_each_pe</a> = <span style="font-style: italic;">.F.</span>,<br>         <a href="chapter_4.2.html#dt_dopr">dt_dopr</a> = <span style="font-style: italic;">900.0</span>, <a href="chapter_4.2.html#averaging_interval_pr">averaging_interval_pr</a> = <span style="font-style: italic;">600.0</span>,<br>         <a href="chapter_4.2.html#dt_averaging_input_pr">dt_averaging_input_pr</a> = <span style="font-style: italic;">10.0</span>,<br>         <a href="chapter_4.2.html#data_output_pr">data_output_pr</a> = <span style="font-style: italic;">'#pt'</span>, <span style="font-style: italic;">'w&rdquo;pt&rdquo;'</span>, <span style="font-style: italic;">'w*pt*'</span>, <span style="font-style: italic;">'wpt'</span>, <span style="font-style: italic;">'w*2'</span>, <span style="font-style: italic;">'pt*2'</span>,<br>         <a href="chapter_4.2.html#cross_profiles">cross_profiles</a> = <span style="font-style: italic;">' pt '</span>, <span style="font-style: italic;">' w"pt" w*pt* wpt '</span>, <span style="font-style: italic;">' w*2 '</span>, <span style="font-style: italic;">' pt*2 '</span>,<br>         <a href="chapter_4.2.html#cross_xtext">cross_xtext</a> = <span style="font-style: italic;">'pot. temperature in K'</span>,<br>                       <span style="font-style: italic;">'heat flux in K ms&gt;-&gt;1'</span>,<br>                       <span style="font-style: italic;">'velocity variance in m&gt;2s&gt;-&gt;2'</span>,<br>                       <span style="font-style: italic;">'temperature variance in K&gt;2'</span>,<br>         <a href="chapter_4.2.html#z_max_do1d">z_max_do1d</a> = <span style="font-style: italic;">1500.0</span>,   /</pre>
36<p style="line-height: 100%;"><br>
37<br>
38</p>
39<p style="line-height: 100%;">The initialization parameters (<tt><font style="font-size: 10pt;" size="2">&amp;inipar</font></tt>)
40are located at the beginning of the file. For analysis of a
41convective boundary layer of approx. 1000 m thickness the horizontal
42size of the model domain should amount to at least 2 km x 2 km. In
43order to resolve the convective structures a grid spacing of <b>dx</b>
44=
45<b>dy</b> = <b>dz</b> = <i>50 m</i> is enough, since the typical
46diameter of convective plumes is more than 100 m. Thereby the
47upper array index in the two horizontal directions needs to be <b>nx</b>
48= <b>ny</b> = <i>39</i>. <font color="#000000">Since in
49each case the lower array index has the value 0, 40 grid points are
50used along both horizontal directions.</font> In the vertical direction
51the domain must be high enough to include the entrainment processes at
52the top of the boundary layer as well as the propagation of gravity
53waves, which were stimulated by
54the convection. However, in the stably stratified region the grid
55resolution has not necessarily to be as high as within the boundary
56layer. This can be obtained by a vertical stretching of the grid
57starting
58from 1200 m via <b>dz_stretch_level</b> = <i>1200.0 m.</i> This saves
59grid points and computing time. <font color="#800000">T</font><font color="#000000">he
60upper boundary of the model is located at (see </font><a href="chapter_4.1.html#dz_stretch_factor"><font color="#000000">dz_stretch_factor</font></a><font color="#000000">)
61&hellip; m (computed by the model)</font>.</p><p style="line-height: 100%;">Fast Fourier transformations are calculated using the Temperton-algorithm, which -on the IBM Regatta- is faster than the default system-specific algorithm (from IBM essl library).</p><p style="line-height: 100%;">The initial profiles for
62wind and temperature can be assigned via <b>initializing_actions</b>
63= <span style="font-style: italic;">'set_constant_profiles'</span>.
64The wind speed, constant with
65height, amounts to <b>ug_surface</b> = <b>vg_surface</b> = <i>0.0 m/s</i>. In order
66to allow for a fast onset of convection, a neutral stratified layer up
67to z
68= 800 m capped by an inversion with dtheta/dz = 1K/100 m is given:
69<b>pt_vertical_gradient</b> = <i>0.0, 1.0</i>,
70<b>pt_vertical_gradient_level</b> = <i>0.0, 800.0.</i> The surface
71temperature, which by default amounts to 300 K, provides the fixed
72point for the temperature profile (see <a href="chapter_4.1.html#pt_surface">pt_surface</a>).
73Convection is driven by a given, near-surface sensible heat flux via <b>surface_heatflux</b>
74= <i>0.1 K m/s.</i> A given surface sensible heta flux requires the
75bottom boundary condition for potential temperature to be <b>bc_pt_b</b>
76=
77<span style="font-style: italic;">'neumann'</span> . Thus
78all initialization parameters are determined. These can not be
79changed during the run (also not for restart runs). </p>
80<p style="line-height: 100%;">Now the run parameters (<tt><font style="font-size: 10pt;" size="2">&amp;d3par</font></tt>)
81must be specified. To produce a quasi stationary boundary layer the
82simulated time should be at least one hour, i.e. <b>end_time</b> = <i>3600
83s.</i> To stimulate convection, the initially homogeneous (zero) wind
84field must be disturbed (<b>create_disturbances</b> = <i>.T.</i>).
85These perturbations should be repeated in a temporal interval of
86<b>dt_disturb</b> = <i>150.0 s</i> until the energy of the
87perturbations exceeds the value <b>disturbance_energy_limit</b> = 0.<i>01
88m<sup>2</sup>/s<sup>2</sup></i>. After each time step run time
89informations (e.g. size of the timestep, maximum velocities, etc.) are
90to be written to the local file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>
91(<b>dt_run_control</b> = <i>0.0 s</i>).</p><p style="line-height: 100%;">Instantaneous cross section data of vertical velocity (<span style="font-style: italic;">w</span>) and potential temperature (<span style="font-style: italic;">pt</span>) are to be output for horizontal (<span style="font-style: italic;">xy</span>) and vertical (<span style="font-style: italic;">xz</span>) cross sections, and additionally, time averaged (<span style="font-style: italic;">av</span>) vertical cross section data are to be output for the vertical velocity: <span style="font-weight: bold;">data_output</span> = <span style="font-style: italic;">'w_xy'</span>, <span style="font-style: italic;">'w_xz'</span>, <span style="font-style: italic;">'w_xz_av'</span>, <span style="font-style: italic;">'pt_xy'</span>, <span style="font-style: italic;">'pt_xz'</span>. Output of instantaneous (time averaged) data is done after each 900 (1800)s: <span style="font-weight: bold;">dt_data_output</span> = <span style="font-style: italic;">900.0</span>, <span style="font-weight: bold;">dt_data_output_av</span> = <span style="font-style: italic;">1800.0</span>. The averaged data are time averaged over the last 900.0 s, where the temporal interval of data entering the average is 10 s: <span style="font-weight: bold;">averaging_interval</span> = <span style="font-style: italic;">900.0</span>, <span style="font-weight: bold;">dt_averaging_input</span> = <span style="font-style: italic;">10.0</span>.
92Horizontal cross sections are output for vertical levels with grid
93index k=2 and k=10, vertical cross sections are output for index j=20: <span style="font-weight: bold;">section_xy</span> = <span style="font-style: italic;">2</span>, <span style="font-style: italic;">10</span>, <span style="font-weight: bold;">section_xz</span> = <span style="font-style: italic;">20</span>. For runs on more than one processor, cross section data are collected and output on PE0: <span style="font-weight: bold;">data_output_2d_on_each_pe</span> = <span style="font-style: italic;">.F.</span>.</p><p style="line-height: 100%;">Output
94of vertical profiles is to be done after each 900 s. The profiles shall
95be temporally averaged<font color="#000000"> over the last <font color="#000000">600 </font>seconds, </font>whereby
96the temporal interval of the profiles entering the average has to be
9710 s: <b>dt_dopr</b> = <i>900.0 s</i>, <b>averaging_interval_pr</b> =
98<i>600.0 s</i>, <b>dt_averaging_input_pr</b> = <i>10.0 s.</i> The temperature
99profile including the initial temperature profile (therefore <span style="font-style: italic;">'#pt'</span>),
100the subgrid scale, resolved and total vertical sensible heat flux as
101well as the variances of the vertical velocity and the potential
102temperature are to be output:&nbsp; <b>data_output_pr</b> = <span style="font-style: italic;">'#pt'</span><i>, 'w"pt&rdquo;',
103'w*pt*', 'wpt', 'w*2', 'pt*2'</i>.</p><p style="line-height: 100%;">If the data output format for graphic software <span style="font-weight: bold;">profil</span> is selected (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>), the temperature
104profile and the individual variances are to be drawn into independent
105coordinate systems, and in contrast to this all heat flux profiles are to
106be
107drawn into the same system: <b>cross_profiles</b> = <span style="font-style: italic;">'pt'</span><i>,
108'w"pt"w*pt*wpt', 'w*2', 'pt*2'</i>. The legend of the x
109axes of these systems is set to <b>cross_xtext</b>= <i>'pot.
110temperature in K', 'heat flux in K ms&gt;-&gt;1', 'velocity variance
111in m&gt;2s&gt;-&gt;2', 'temperature variance in K&gt;2'</i>.
112The profiles are to be drawn up to a height level of <b>z_max_do1d</b>
113=
114<i>1500.0 m</i>. </p>
115<p style="line-height: 100%;">Before starting the mo<font color="#000000">del
116on the parallel computer, the number of processing elements must be
117specified.</font> Since relatively few grid points are used for
118this run, choosing of e.g. 8 PEs is sufficient. By default, a 1d domain
119decomposition along x is used on the IBM-Regatta, which means that a
120virtual processor topology (grid) of 8*1 (x*y) is used. (<span style="font-weight: bold;">Note:</span> the user may adjust this
121default domain decomposition with the help of the parameters <a href="chapter_4.1.html#npex">npex</a>
122and <a href="chapter_4.1.html#npey">npey</a>).
123</p>
124<p style="line-height: 100%;">Provided that the parameters
125file described above are set within the file </p>
126<ul>
127  <pre style="margin-bottom: 0.5cm; line-height: 100%;"><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/INPUT/example_p3d</font></pre>
128</ul>
129<p style="line-height: 100%;">and that the conditions mentioned in the
130first sections of <a href="chapter_3.2.html">chapter
1313.2</a> are met, the model run can be started with the command </p>
132<p style="line-height: 100%;"><font face="Cumberland, monospace"><font style="font-size: 10pt;" size="2">mrun
133-d example -h ibmh -K parallel -X 8 -T 8 -t 1800 -q cdev -r &ldquo;d3# xy# xz# pr#&rdquo;</font></font></p>
134<p style="line-height: 100%;">The output files will appear in the
135directories </p>
136<blockquote style="line-height: 100%;"><tt><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/MONITORING</font></tt><font style="font-size: 10pt;" size="2"><br>
137  </font><tt><font style="font-size: 10pt;" size="2">~/palm/current_version/JOBS/example/OUTPUT
138,</font></tt></blockquote>
139<p style="line-height: 100%;">while the job protocol will appear in
140directory <font style="font-size: 10pt;" size="2"><font face="Cumberland, monospace">~/</font></font><tt><font style="font-size: 10pt;" size="2"><font face="Cumberland, monospace">job_queue</font></font></tt>.
141<br>
142&nbsp; </p>
143<hr>
144<p style="line-height: 100%;"><br>
145<font color="#000080"><font color="#000080"><a href="chapter_4.3.html"><font color="#000080"><img name="Grafik1" src="left.gif" align="bottom" border="2" height="32" width="32"></font></a><a href="index.html"><font color="#000080"><img name="Grafik2" src="up.gif" align="bottom" border="2" height="32" width="32"></font></a><a href="chapter_4.5.html"><font color="#000080"><img name="Grafik3" src="right.gif" align="bottom" border="2" height="32" width="32"></font></a></font></font></p>
146<p style="line-height: 100%;"><i>Last change:&nbsp; 13/04/06</i> (SR)
147<br>
148&nbsp; <br>
149&nbsp; </p>
150</body></html>
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