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Changeset 344 for palm


Ignore:
Timestamp:
Jun 24, 2009 2:12:22 PM (15 years ago)
Author:
maronga
Message:

documentation update for the coupling

Location:
palm/trunk/DOC/app
Files:
3 edited

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  • palm/trunk/DOC/app/chapter_3.8.html

    r197 r344  
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    25 
    26 <h3 style="line-height: 100%;">3.8 Coupled model runs</h3>
    27 
    28 <p style="line-height: 100%;">Starting from version 3.4
    29 PALM allows coupled atmosphere-ocean model runs. By analogy with the
    30 modular structure of PALM, <span style="font-weight: bold;">mrun</span>
    31 starts the coupled model as two concurrent executables, the atmosphere
    32 version and&nbsp;the ocean version of PALM.</p>
    33 
    34 <p style="line-height: 100%;">Currently, the coupler
    35 is at an experimental stage using a simple MPI2 intercommunicator that
    36 matches the atmosphere and ocean processors one-to-one. This approach
    37 has&nbsp;limited flexibility and performance, because it requires
    38 identical horizontal numerical grids and it uses the same number of
    39 atmosphere and ocean processors, which does not necessarily guarrantee
    40 a good load balancing.</p>
    41 
    42 <p style="line-height: 100%;">The coupler establishes a
    43 one-way interaction between the
    44 atmosphere and the ocean. The atmosphere sends its bottom surface
    45 fluxes
    46 (temperature, humidity, momentum) to the ocean. The ocean sends its top
    47 surface temperature to the atmosphere. The atmosphere assumes
    48 saturation of humidity and zero wind speed at its bottom surface. For
    49 calculations with <a href="chapter_4.1.html#humidity">humidity</a>
    50 = .T. the atmospheric evaporation leads to a salinity flux in the ocean
    51 (see e.g. Steinhorn 1991, JPO 21, p. 1681).</p>
    52 
    53 <p style="line-height: 100%;">The full MPI-2
    54 standard must be available in order to use the coupling, and it must be
    55 activated by adding the preprocessor directive <tt><font style="font-size: 10pt;" size="2">-D__mpi2</font></tt>
    56 to <tt><font style="font-size: 10pt;" size="2">cpp_options</font></tt>
    57 in the .mrun.config configuration file. (Note: MPI-2 is
    58 not available for the IBM-Regatta systems.) To start a
    59 coupled&nbsp;model run,
    60 this must be requested with the <b>mrun</b> option <tt><font style="font-size: 10pt;" size="2">-Y</font>.</tt>
    61 This tells <span style="font-weight: bold;">mrun</span>
    62 to start two PALM executables. Coupled runs are only possible in
    63 parallel mode, which means that the <b>mrun</b> option <tt><font style="font-size: 10pt;" size="2">-K parallel</font></tt>
    64 must also be set.&nbsp;The <b>mrun</b> call
    65 for coupled runs has to include the following coupling-related options:
    66 </p>
    67 
    68 <ul>
    69 
    70   <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
    71 &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>
    72 
    73 </ul>
    74 
    75 <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
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     21<H3 STYLE="line-height: 100%">3.8 Coupled model runs</H3>
     22<P STYLE="line-height: 100%">Starting from version 3.4 PALM allows
     23coupled atmosphere-ocean model runs. By analogy with the modular
     24structure of PALM, <B>mrun</B> starts the coupled model as two
     25concurrent executables, the atmosphere version and&nbsp;the ocean
     26version of PALM.</P>
     27<P STYLE="line-height: 100%">Currently, the coupler is at an
     28experimental stage using either a MPI2 (more flexible) or a MPI1
     29intercommunicator that matches the atmosphere and ocean processors
     30one-to-one. This approach has&nbsp;limited flexibility and
     31performance, because it requires identical horizontal numerical grids
     32and it uses the same number of atmosphere and ocean processors, which
     33does not necessarily guarrantee a good load balancing.</P>
     34<P STYLE="line-height: 100%">The coupler establishes a one-way
     35interaction between the atmosphere and the ocean. The atmosphere
     36sends its bottom surface fluxes (temperature, humidity, momentum) to
     37the ocean. The ocean sends its top surface temperature to the
     38atmosphere. The atmosphere assumes saturation of humidity and zero
     39wind speed at its bottom surface. For calculations with <A HREF="chapter_4.1.html#humidity">humidity</A>
     40= .T. the atmospheric evaporation leads to a salinity flux in the
     41ocean (see e.g. Steinhorn 1991, JPO 21, p. 1681).</P>
     42<P STYLE="line-height: 100%">If the full MPI-2 standard is available,
     43it can be activated by adding the preprocessor directive <TT><FONT SIZE=2>-D__mpi2</FONT></TT>
     44to <TT><FONT SIZE=2>cpp_options</FONT></TT> in the .mrun.config
     45configuration file. Otherwise, PALM will use a coupling via MPI1. To
     46start a coupled&nbsp;model run, this must be requested with the <B>mrun</B>
     47option <TT><FONT SIZE=2>-Y “#1 #2”</FONT></TT><TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>,
     48where </FONT></FONT></TT><TT><FONT FACE="Andale Mono"><FONT SIZE=2>#1</FONT></FONT></TT><TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>
     49is the number of processors for the atmospheric and </FONT></FONT></TT><TT><FONT FACE="Andale Mono"><FONT SIZE=2>#2</FONT></FONT></TT><TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>
     50the number of processors for the oceanic version of PALM (Please note
     51that currently only one-to-one topologies are supported and </FONT></FONT></TT><TT><FONT FACE="Andale Mono"><FONT SIZE=2>#1</FONT></FONT></TT><TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>
     52must be equal to </FONT></FONT></TT><TT><FONT FACE="Andale Mono"><FONT SIZE=2>#2</FONT></FONT></TT><TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>).
     53</FONT></FONT></TT><FONT FACE="Times New Roman, serif"><FONT SIZE=3>Thi</FONT></FONT>s
     54tells <B>mrun</B> to start two PALM executables. Coupled runs are
     55only possible in parallel mode, which means that the <B>mrun</B>
     56option <TT><FONT SIZE=2>-K parallel</FONT></TT> must also be set.&nbsp;The
     57<B>mrun</B> call for coupled runs has to include the following
     58coupling-related options:
     59</P>
     60<UL>
     61        <P STYLE="line-height: 100%"><TT><FONT SIZE=2>mrun </FONT></TT><FONT SIZE=2>...</FONT><TT>
     62        </TT><TT><FONT SIZE=2>-K parallel -r “d3# d3o# </FONT></TT><FONT SIZE=2>...</FONT><TT>”
     63        </TT><TT><FONT SIZE=2>-X </FONT></TT><FONT SIZE=2>...</FONT><TT> </TT><TT><FONT SIZE=2>-Y
     64        “#1 #2”</FONT></TT><TT>.</TT></P>
     65</UL>
     66<P STYLE="line-height: 100%">The <TT><FONT SIZE=2>-X </FONT></TT><FONT SIZE=2>...</FONT><TT>&nbsp;</TT>option
    7667here specifies the total number of processors assigned to the coupled
    77 model. Currently, half of them are assigned to each of the two coupled
    78 executables. Therefore it is advisable to specify an even number
    79 with&nbsp;<tt><font style="font-size: 10pt;" size="2">-X </font></tt><font style="font-size: 10pt;" size="2">...</font><tt>
    80 </tt>. Otherwise, in case of an odd total number of processors,
    81 one processor remains idle.</p>
    82 
    83 <p style="line-height: 100%;">Each coupled executable has
    84 its own, unique set of I/O filenames; <a href="chapter_3.4.html#coupled">chapter 3.4</a> gives
    85 information on file name conventions of coupled runs. The configuration
    86 file .mrun.config has to be extended for coupled runs. It is
    87 recommended to duplicate existing file connection identifiers such as
    88 "d3#", "pr#" etc. using the coupled ocean filenames accordingly. For
    89 example,&nbsp;the example of the previous chapters could be
    90 duplicated as follows:</p>
    91 
    92 <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>
    93 
    94 <p style="line-height: 100%;">The coupled ocean model
    95 filenames 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
    96 be specified as given in <a href="chapter_3.4.html#coupled">chapter
    97 3.4</a>; the file connection identifiers (e.g.&nbsp; <font style="font-size: 10pt;" size="2">d3o#</font>)
    98 and 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>)
    99 may be changed at the user's discretion.</p>
    100 
    101 <p style="line-height: 100%;">The coupler requires the
    102 following 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>
    103 and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>:
    104 <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>,
    105 <a href="chapter_4.2.html#dt_restart">dt_restart</a>.
    106 In the coupled atmosphere executable,&nbsp;<a href="chapter_4.2.html#bc_pt_b">bc_pt_b</a> is
    107 internally set and does not need to be prescribed; in the coupled ocean
    108 executable, <a href="chapter_4.2.html#bc_uv_t">bc_uv_t</a>&nbsp;is
     68model. Currently, half of them are assigned to each of the two
     69coupled executables. Therefore it is advisable to specify an even
     70number with&nbsp;<TT><FONT SIZE=2>-X </FONT></TT><FONT SIZE=2>...</FONT><TT>
     71</TT>. Otherwise, in case of an odd total number of processors, one
     72processor remains idle.</P>
     73<P STYLE="line-height: 100%">Each coupled executable has its own,
     74unique set of I/O filenames; <A HREF="chapter_3.4.html#coupled">chapter
     753.4</A> gives information on file name conventions of coupled runs.
     76The configuration file .mrun.config has to be extended for coupled
     77runs. It is recommended to duplicate existing file connection
     78identifiers such as &quot;d3#&quot;, &quot;pr#&quot; etc. using the
     79coupled ocean filenames accordingly. For example,&nbsp;the example of
     80the previous chapters could be duplicated as follows:</P>
     81<PRE STYLE="line-height: 100%"><A HREF="chapter_3.4.html#PARIN"><FONT SIZE=2>PARIN</FONT></A> <FONT SIZE=2>in:job:npe d3# ~/palm/current_version/JOBS/$fname/INPUT _p3d</FONT>
     82<FONT SIZE=2>PARIN in:job:npe d3f ~/palm/current_version/JOBS/$fname/INPUT _p3df</FONT>
     83<A HREF="chapter_3.4.html#BININ"><FONT SIZE=2>BININ</FONT></A> <FONT SIZE=2>in:loc d3f ~/palm/current_version/JOBS/$fname/OUTPUT _d3d</FONT>
     84<FONT SIZE=2>#</FONT>
     85<A HREF="chapter_3.4.html#BINOUT"><FONT SIZE=2>BINOUT</FONT></A> <FONT SIZE=2>out:loc restart ~/palm/current_version/JOBS/$fname/OUTPUT _d3d</FONT>
     86<FONT SIZE=2>#</FONT>
     87<A HREF="chapter_3.4.html#RUN_CONTROL"><FONT SIZE=2>RUN_CONTROL</FONT></A> <FONT SIZE=2>out:loc:tr d3# ~/palm/current_version/JOBS/$fname/MONITORING _rc</FONT>
     88<A HREF="chapter_3.4.html#HEADER"><FONT SIZE=2>HEADER</FONT></A> <FONT SIZE=2>out:loc:tr d3# ~/palm/current_version/JOBS/$fname/MONITORING _header</FONT>
     89<A HREF="chapter_3.4.html#PLOT1D_PAR"><FONT SIZE=2>PLOT1D_PAR</FONT></A> <FONT SIZE=2>out:loc:tr pr# ~/palm/current_version/JOBS/$fname/OUTPUT _pr_par</FONT>
     90<A HREF="chapter_3.4.html#PLOT1D_DATA"><FONT SIZE=2>PLOT1D_DATA</FONT></A> <FONT SIZE=2>out:loc:tr pr# ~/palm/current_version/JOBS/$fname/OUTPUT _pr_in</FONT>
     91<FONT SIZE=2>#</FONT>
     92<FONT SIZE=2>PARIN</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> in:job:npe d3</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2># ~/palm/current_version/JOBS/$fname/INPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_p3d</FONT>
     93<FONT SIZE=2>PARIN</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> in:job:npe d3</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2>f ~/palm/current_version/JOBS/$fname/INPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_p3df</FONT>
     94<FONT SIZE=2>BININ</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> in:loc d3</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2>f ~/palm/current_version/JOBS/$fname/OUTPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_d3d</FONT>
     95<FONT SIZE=2>#</FONT>
     96<FONT SIZE=2>BINOUT</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> out:loc restart ~/palm/current_version/JOBS/$fname/OUTPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_d3d</FONT>
     97<FONT SIZE=2>#</FONT>
     98<FONT SIZE=2>RUN_CONTROL</FONT><FONT SIZE=2><B>_O</B></FONT> <FONT SIZE=2>out:loc:tr d3</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2># ~/palm/current_version/JOBS/$fname/MONITORING </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_rc</FONT>
     99<FONT SIZE=2>HEADER</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> out:loc:tr d3</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2># ~/palm/current_version/JOBS/$fname/MONITORING </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_header</FONT>
     100<FONT SIZE=2>PLOT1D_PAR</FONT><FONT SIZE=2><B>_O</B></FONT> <FONT SIZE=2>out:loc:tr pr</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2># ~/palm/current_version/JOBS/$fname/OUTPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_pr_par</FONT>
     101<FONT SIZE=2>PLOT1D_DATA</FONT><FONT SIZE=2><B>_O</B></FONT><FONT SIZE=2> out:loc:tr pr</FONT><FONT SIZE=2><B>o</B></FONT><FONT SIZE=2># ~/palm/current_version/JOBS/$fname/OUTPUT </FONT><FONT SIZE=2><B>_o</B></FONT><FONT SIZE=2>_pr_in</FONT></PRE><P STYLE="line-height: 100%">
     102The coupled ocean model filenames in the first column (e.g.
     103<A HREF="chapter_3.4.html#PARIN"><FONT SIZE=2>PARIN_O</FONT></A>)&nbsp;must
     104be specified as given in <A HREF="chapter_3.4.html#coupled">chapter
     1053.4</A>; the file connection identifiers (e.g.&nbsp; <FONT SIZE=2>d3o#</FONT>)
     106and the file name extension (e.g. &nbsp;<FONT SIZE=2>_o_p3d</FONT>)
     107may be changed at the user's discretion.</P>
     108<P STYLE="line-height: 100%">The coupler requires the following
     109parameters to be equal in both <A HREF="chapter_3.4.html#PARIN"><FONT SIZE=2>PARIN</FONT></A>
     110and&nbsp;<A HREF="chapter_3.4.html#PARIN"><FONT SIZE=2>PARIN_O</FONT></A>:
     111<A HREF="chapter_4.1.html#dx">dx</A>, <A HREF="chapter_4.1.html#dy">dy</A>,
     112<A HREF="chapter_4.1.html#nx">nx</A>, <A HREF="chapter_4.1.html#ny">ny</A>,
     113<A HREF="chapter_4.2.html#dt_coupling">dt_coupling</A>, <A HREF="chapter_4.2.html#end_time">end_time</A>,
     114<A HREF="chapter_4.2.html#restart_time">restart_time</A>, <A HREF="chapter_4.2.html#dt_restart">dt_restart</A>.
     115In the coupled atmosphere executable,&nbsp;<A HREF="chapter_4.2.html#bc_pt_b">bc_pt_b</A>
     116is internally set and does not need to be prescribed; in the coupled
     117ocean executable, <A HREF="chapter_4.2.html#bc_uv_t">bc_uv_t</A>&nbsp;is
    109118internally set ('neumann') and does not need to be prescribed. The
    110 coupled ocean parameter file&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>
    111 should include dummy REAL value assignments to both <a href="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</a>
    112 and&nbsp;<a href="chapter_4.1.html#top_momentumflux_v">top_momentumflux_v</a>
     119coupled ocean parameter file&nbsp;<A HREF="chapter_3.4.html#PARIN"><FONT SIZE=2>PARIN_O</FONT></A>
     120should include dummy REAL value assignments to both
     121<A HREF="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</A>
     122and&nbsp;<A HREF="chapter_4.1.html#top_momentumflux_v">top_momentumflux_v</A>
    113123(e.g.&nbsp;top_momentumflux_u = 0.0, top_momentumflux_v = 0.0) to
    114 enable the momentum flux coupling.</p>
    115 
    116 <p style="line-height: 100%;">The coupling interval <a href="chapter_4.2.html#dt_coupling">dt_coupling</a>
     124enable the momentum flux coupling.</P>
     125<P STYLE="line-height: 100%">The coupling interval <A HREF="chapter_4.2.html#dt_coupling">dt_coupling</A>
    117126must be explicity set. In order to ensure synchronous coupling
    118 throughout the simulation, <a href="chapter_4.2.html#dt_coupling">dt_coupling</a>
    119 should be chosen larger than
    120 <a href="chapter_4.2.html#dt_max">dt_max</a>.</p>
    121 
    122 <hr>
    123 <p style="line-height: 100%;"><br>
    124 
    125 <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_3.9.html"><font color="#000080"><img style="border: 2px solid ; width: 32px; height: 32px;" alt="" src="right.gif" name="Grafik3"></font></a></font></font></p>
    126 
    127 <p style="line-height: 100%;"><i>Last
    128 change:&nbsp;</i> $Id$</p>
    129 
    130 </body></html>
     127throughout the simulation, <A HREF="chapter_4.2.html#dt_coupling">dt_coupling</A>
     128should be chosen larger than <A HREF="chapter_4.2.html#dt_max">dt_max</A>.</P>
     129<P STYLE="line-height: 100%">It's also possible to perform precursor
     130runs (one atmospheric and one oceanic) followed by a coupled restart
     131run. In order to achieve this, the parameter <A HREF="chapter_4.1.html#coupling_start_time">coupling_time_start</A>
     132must be set according to the <A HREF="../misc/precursor_run_control.pdf">documentation.</A></P>
     133<HR>
     134<P STYLE="line-height: 100%"><BR><FONT COLOR="#000080"><A HREF="chapter_3.7.html"><FONT COLOR="#000000"><IMG SRC="left.gif" NAME="Grafik1" ALIGN=BOTTOM WIDTH=32 HEIGHT=32 BORDER=1></FONT></A><A HREF="index.html"><FONT COLOR="#000080"><IMG SRC="up.gif" NAME="Grafik2" ALIGN=BOTTOM WIDTH=32 HEIGHT=32 BORDER=1></FONT></A><A HREF="chapter_3.9.html"><FONT COLOR="#000000"><IMG SRC="right.gif" NAME="Grafik3" ALIGN=BOTTOM WIDTH=32 HEIGHT=32 BORDER=1></FONT></A></FONT></P>
     135<P STYLE="line-height: 100%"><I>Last change:&nbsp;</I> $Id:
     136chapter_3.8.html 197 2008-09-16 15:29:03Z raasch $</P>
     137</BODY>
     138</HTML>

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    29   <title>PALM chapter 4.1</title></head>
    30 <body>
    31 
    32 
    33 
    34 
    35 
    36 
    37 <h3><a name="chapter4.1"></a>4.1
    38 Initialization parameters</h3>
    39 
    40 
    41 
    42 
    43 
    44 
    45 
    46 <br>
    47 
    48 
    49 
    50 
    51 
    52 
    53 <table style="text-align: left; width: 100%;" border="1" cellpadding="2" cellspacing="2">
    54 
    55 
    56 
    57 
    58 
    59 
    60  <tbody>
    61 
    62 
    63 
    64 
    65 
    66 
    67 
    68     <tr>
    69 
    70 
    71 
    72 
    73 
    74 
    75  <td style="vertical-align: top;"><font size="4"><b>Parameter name</b></font></td>
    76 
    77 
    78 
    79 
    80 
    81 
    82 
    83       <td style="vertical-align: top;"><font size="4"><b>Type</b></font></td>
    84 
    85 
    86 
    87 
    88 
    89 
    90 
    91       <td style="vertical-align: top;">
    92      
    93      
    94      
    95      
    96      
    97      
    98       <p><b><font size="4">Default</font></b> <br>
    99 
    100 
    101 
    102 
    103 
    104 
    105  <b><font size="4">value</font></b></p>
    106 
    107 
    108 
    109 
    110 
    111 
    112  </td>
    113 
    114 
    115 
    116 
    117 
    118 
    119 
    120       <td style="vertical-align: top;"><font size="4"><b>Explanation</b></font></td>
    121 
    122 
    123 
    124 
    125 
    126 
    127 
    128     </tr>
    129 
    130 
    131 
    132 
    133 
    134 
    135  <tr>
    136 
    137 
    138 
    139 
    140 
    141 
    142  <td style="vertical-align: top;">
    143      
    144      
    145      
    146      
    147      
    148      
    149       <p><a name="adjust_mixing_length"></a><b>adjust_mixing_length</b></p>
    150 
    151 
    152 
    153 
    154 
    155 
    156 
    157       </td>
    158 
    159 
    160 
    161 
    162 
    163 
    164  <td style="vertical-align: top;">L</td>
    165 
    166 
    167 
    168 
    169 
    170 
    171 
    172       <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
    173 
    174 
    175 
    176 
    177 
    178 
    179  <td style="vertical-align: top;">
    180      
    181      
    182      
    183      
    184      
    185      
    186       <p style="font-style: normal;">Near-surface adjustment of the
    187 mixing length to the Prandtl-layer law.&nbsp; </p>
    188 
    189 
    190 
    191 
    192 
    193 
    194  
    195      
    196      
    197      
    198      
    199      
    200      
    201       <p>Usually
    202 the mixing length in LES models l<sub>LES</sub>
    203 depends (as in PALM) on the grid size and is possibly restricted
    204 further in case of stable stratification and near the lower wall (see
    205 parameter <a href="#wall_adjustment">wall_adjustment</a>).
    206 With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span>
    207 the Prandtl' mixing length l<sub>PR</sub> = kappa * z/phi
    208 is calculated
    209 and the mixing length actually used in the model is set l = MIN (l<sub>LES</sub>,
    210 l<sub>PR</sub>). This usually gives a decrease of the
    211 mixing length at
    212 the bottom boundary and considers the fact that eddy sizes
    213 decrease in the vicinity of the wall.&nbsp; </p>
    214 
    215 
    216 
    217 
    218 
    219 
    220  
    221      
    222      
    223      
    224      
    225      
    226      
    227       <p style="font-style: normal;"><b>Warning:</b> So
    228 far, there is
    229 no good experience with <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> !&nbsp; </p>
    230 
    231 
    232 
    233 
    234 
    235 
    236 
    237      
    238      
    239      
    240      
    241      
    242      
    243       <p>With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> and the
    244 Prandtl-layer being
    245 switched on (see <a href="#prandtl_layer">prandtl_layer</a>)
    246       <span style="font-style: italic;">'(u*)** 2+neumann'</span>
    247 should always be set as the lower boundary condition for the TKE (see <a href="#bc_e_b">bc_e_b</a>),
    248 otherwise the near-surface value of the TKE is not in agreement with
    249 the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz
    250 should provide the same value for K<sub>m</sub>). A warning
    251 is given,
    252 if this is not the case.</p>
    253 
    254 
    255 
    256 
    257 
    258 
    259  </td>
    260 
    261 
    262 
    263 
    264 
    265 
    266  </tr>
    267 
    268 
    269 
    270 
    271 
    272 
    273  <tr>
    274 
    275 
    276 
    277 
    278 
    279 
    280 
    281       <td style="vertical-align: top;">
    282      
    283      
    284      
    285      
    286      
    287      
    288       <p><a name="alpha_surface"></a><b>alpha_surface</b></p>
    289 
    290 
    291 
    292 
    293 
    294 
    295 
    296       </td>
    297 
    298 
    299 
    300 
    301 
    302 
    303  <td style="vertical-align: top;">R<br>
    304 
    305 
    306 
    307 
    308 
    309 
    310  </td>
    311 
    312 
    313 
    314 
    315 
    316 
    317 
    318       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
    319 
    320 
    321 
    322 
    323 
    324 
    325  </td>
    326 
    327 
    328 
    329 
    330 
    331 
    332 
    333       <td style="vertical-align: top;">
    334      
    335      
    336      
    337      
    338      
    339      
    340       <p style="font-style: normal;">Inclination of the model domain
    341 with respect to the horizontal (in degrees).&nbsp; </p>
    342 
    343 
    344 
    345 
    346 
    347 
    348  
    349      
    350      
    351      
    352      
    353      
    354      
    355       <p style="font-style: normal;">By means of <b>alpha_surface</b>
    356 the model domain can be inclined in x-direction with respect to the
    357 horizontal. In this way flows over inclined surfaces (e.g. drainage
    358 flows, gravity flows) can be simulated. In case of <b>alpha_surface
    359       </b>/= <span style="font-style: italic;">0</span>
    360 the buoyancy term
    361 appears both in
    362 the equation of motion of the u-component and of the w-component.<br>
    363 
    364 
    365 
    366 
    367 
    368 
    369 
    370       </p>
    371 
    372 
    373 
    374 
    375 
    376 
    377  
    378      
    379      
    380      
    381      
    382      
    383      
    384       <p style="font-style: normal;">An inclination
    385 is only possible in
    386 case of cyclic horizontal boundary conditions along x AND y (see <a href="#bc_lr">bc_lr</a>
    387 and <a href="#bc_ns">bc_ns</a>) and <a href="#topography">topography</a> = <span style="font-style: italic;">'flat'</span>. </p>
    388 
    389 
    390 
    391 
    392 
    393 
    394 
    395      
    396      
    397      
    398      
    399      
    400      
    401       <p>Runs with inclined surface still require additional
    402 user-defined code as well as modifications to the default code. Please
    403 ask the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/PALM_group.html#0">PALM
    404 developer&nbsp; group</a>.</p>
    405 
    406 
    407 
    408 
    409 
    410 
    411  </td>
    412 
    413 
    414 
    415 
    416 
    417 
    418  </tr>
    419 
    420 
    421 
    422 
    423 
    424 
    425 
    426     <tr>
    427 
    428 
    429 
    430 
    431 
    432 
    433  <td style="vertical-align: top;">
    434      
    435      
    436      
    437      
    438      
    439      
    440       <p><a name="bc_e_b"></a><b>bc_e_b</b></p>
    441 
    442 
    443 
    444 
    445 
    446 
    447  </td>
    448 
    449 
    450 
    451 
    452 
    453 
    454 
    455       <td style="vertical-align: top;">C * 20</td>
    456 
    457 
    458 
    459 
    460 
    461 
    462  <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
    463 
    464 
    465 
    466 
    467 
    468 
    469 
    470       <td style="vertical-align: top;">
    471      
    472      
    473      
    474      
    475      
    476      
    477       <p style="font-style: normal;">Bottom boundary condition of the
    478 TKE.&nbsp; </p>
    479 
    480 
    481 
    482 
    483 
    484 
    485  
    486      
    487      
    488      
    489      
    490      
    491      
    492       <p><b>bc_e_b</b> may be
    493 set to&nbsp;<span style="font-style: italic;">'neumann'</span>
    494 or <span style="font-style: italic;">'(u*) ** 2+neumann'</span>.
    495       <b>bc_e_b</b>
    496 = <span style="font-style: italic;">'neumann'</span>
    497 yields to
    498 e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated
    499 via the prognostic TKE equation. Choice of <span style="font-style: italic;">'(u*)**2+neumann'</span>
    500 also yields to
    501 e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated
    502 diagnostically by e(k=1)=(us/0.1)**2. However, this is only allowed if
    503 a Prandtl-layer is used (<a href="#prandtl_layer">prandtl_layer</a>).
    504 If this is not the case, a warning is given and <b>bc_e_b</b>
    505 is reset
    506 to <span style="font-style: italic;">'neumann'</span>.&nbsp;
    507       </p>
    508 
    509 
    510 
    511 
    512 
    513 
    514  
    515      
    516      
    517      
    518      
    519      
    520      
    521       <p style="font-style: normal;">At the top
    522 boundary a Neumann
    523 boundary condition is generally used: (e(nz+1) = e(nz)).</p>
    524 
    525 
    526 
    527 
    528 
    529 
    530  </td>
    531 
    532 
    533 
    534 
    535 
    536 
    537 
    538     </tr>
    539 
    540 
    541 
    542 
    543 
    544 
    545  <tr>
    546 
    547 
    548 
    549 
    550 
    551 
    552  <td style="vertical-align: top;">
    553      
    554      
    555      
    556      
    557      
    558      
    559       <p><a name="bc_lr"></a><b>bc_lr</b></p>
    560 
    561 
    562 
    563 
    564 
    565 
    566 
    567       </td>
    568 
    569 
    570 
    571 
    572 
    573 
    574  <td style="vertical-align: top;">C * 20</td>
    575 
    576 
    577 
    578 
    579 
    580 
    581 
    582       <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
    583 
    584 
    585 
    586 
    587 
    588 
    589 
    590       <td style="vertical-align: top;">Boundary
    591 condition along x (for all quantities).<br>
    592 
    593 
    594 
    595 
    596 
    597 
    598  <br>
    599 
    600 
    601 
    602 
    603 
    604 
    605 
    606 By default, a cyclic boundary condition is used along x.<br>
    607 
    608 
    609 
    610 
    611 
    612 
    613  <br>
    614 
    615 
    616 
    617 
    618 
    619 
    620 
    621       <span style="font-weight: bold;">bc_lr</span> may
    622 also be
    623 assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
    624 (inflow from left, outflow to the right) or <span style="font-style: italic;">'radiation/dirichlet'</span>
    625 (inflow from
    626 right, outflow to the left). This requires the multi-grid method to be
    627 used for solving the Poisson equation for perturbation pressure (see <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">psolver</a>)
    628 and it also requires cyclic boundary conditions along y (see&nbsp;<a href="#bc_ns">bc_ns</a>).<br>
    629 
    630 
    631 
    632 
    633 
    634 
    635  <br>
    636 
    637 
    638 
    639 
    640 
    641 
    642 
    643 In case of these non-cyclic lateral boundaries, a Dirichlet condition
    644 is used at the inflow for all quantities (initial vertical profiles -
    645 see <a href="#initializing_actions">initializing_actions</a>
    646 - are fixed during the run) except u, to which a Neumann (zero
    647 gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
    648 gradient) condition is used for the scalars. For perturbation
    649 pressure Neumann (zero gradient) conditions are assumed both at the
    650 inflow and at the outflow.<br>
    651 
    652 
    653 
    654 
    655 
    656 
    657  <br>
    658 
    659 
    660 
    661 
    662 
    663 
    664 
    665 When using non-cyclic lateral boundaries, a filter is applied to the
    666 velocity field in the vicinity of the outflow in order to suppress any
    667 reflections of outgoing disturbances (see <a href="#km_damp_max">km_damp_max</a>
    668 and <a href="#outflow_damping_width">outflow_damping_width</a>).<br>
    669 
    670 
    671 
    672 
    673 
    674 
    675 
    676       <br>
    677 
    678 
    679 
    680 
    681 
    682 
    683 
    684 In order to maintain a turbulent state of the flow, it may be
    685 neccessary to continuously impose perturbations on the horizontal
    686 velocity field in the vicinity of the inflow throughout the whole run.
    687 This can be switched on using <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#create_disturbances">create_disturbances</a>.
    688 The horizontal range to which these perturbations are applied is
    689 controlled by the parameters <a href="#inflow_disturbance_begin">inflow_disturbance_begin</a>
    690 and <a href="#inflow_disturbance_end">inflow_disturbance_end</a>.
    691 The vertical range and the perturbation amplitude are given by <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_b</a>,
    692       <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_t</a>,
    693 and <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_amplitude</a>.
    694 The time interval at which perturbations are to be imposed is set by <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#dt_disturb">dt_disturb</a>.<br>
    695 
    696 
    697 
    698 
    699 
    700 
    701 
    702       <br>
    703 
    704 
    705 
    706 
    707 
    708 
    709 
    710 In case of non-cyclic horizontal boundaries <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#call_psolver_at_all_substeps">call_psolver
    711 at_all_substeps</a> = .T. should be used.<br>
    712 
    713 
    714 
    715 
    716 
    717 
    718  <br>
    719 
    720 
    721 
    722 
    723 
    724 
    725  <span style="font-weight: bold;">Note:</span><br>
    726 
    727 
    728 
    729 
    730 
    731 
    732 
    733 Using non-cyclic lateral boundaries requires very sensitive adjustments
    734 of the inflow (vertical profiles) and the bottom boundary conditions,
    735 e.g. a surface heating should not be applied near the inflow boundary
    736 because this may significantly disturb the inflow. Please check the
    737 model results very carefully.</td>
    738 
    739 
    740 
    741 
    742 
    743 
    744  </tr>
    745 
    746 
    747 
    748 
    749 
    750 
    751  <tr>
    752 
    753 
    754 
    755 
    756 
    757 
    758  <td style="vertical-align: top;">
    759      
    760      
    761      
    762      
    763      
    764      
    765       <p><a name="bc_ns"></a><b>bc_ns</b></p>
    766 
    767 
    768 
    769 
    770 
    771 
    772 
    773       </td>
    774 
    775 
    776 
    777 
    778 
    779 
    780  <td style="vertical-align: top;">C * 20</td>
    781 
    782 
    783 
    784 
    785 
    786 
    787 
    788       <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
    789 
    790 
    791 
    792 
    793 
    794 
    795 
    796       <td style="vertical-align: top;">Boundary
    797 condition along y (for all quantities).<br>
    798 
    799 
    800 
    801 
    802 
    803 
    804  <br>
    805 
    806 
    807 
    808 
    809 
    810 
    811 
    812 By default, a cyclic boundary condition is used along y.<br>
    813 
    814 
    815 
    816 
    817 
    818 
    819  <br>
    820 
    821 
    822 
    823 
    824 
    825 
    826 
    827       <span style="font-weight: bold;">bc_ns</span> may
    828 also be
    829 assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
    830 (inflow from rear ("north"), outflow to the front ("south")) or <span style="font-style: italic;">'radiation/dirichlet'</span>
    831 (inflow from front ("south"), outflow to the rear ("north")). This
    832 requires the multi-grid
    833 method to be used for solving the Poisson equation for perturbation
    834 pressure (see <a href="chapter_4.2.html#psolver">psolver</a>)
    835 and it also requires cyclic boundary conditions along x (see<br>
    836 
    837 
    838 
    839 
    840 
    841 
    842  <a href="#bc_lr">bc_lr</a>).<br>
    843 
    844 
    845 
    846 
    847 
    848 
    849  <br>
    850 
    851 
    852 
    853 
    854 
    855 
    856 
    857 In case of these non-cyclic lateral boundaries, a Dirichlet condition
    858 is used at the inflow for all quantities (initial vertical profiles -
    859 see <a href="chapter_4.1.html#initializing_actions">initializing_actions</a>
    860 - are fixed during the run) except u, to which a Neumann (zero
    861 gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
    862 gradient) condition is used for the scalars. For perturbation
    863 pressure Neumann (zero gradient) conditions are assumed both at the
    864 inflow and at the outflow.<br>
    865 
    866 
    867 
    868 
    869 
    870 
    871  <br>
    872 
    873 
    874 
    875 
    876 
    877 
    878 
    879 For further details regarding non-cyclic lateral boundary conditions
    880 see <a href="#bc_lr">bc_lr</a>.</td>
    881 
    882 
    883 
    884 
    885 
    886 
    887  </tr>
    888 
    889 
    890 
    891 
    892 
    893 
    894 
    895     <tr>
    896 
    897 
    898 
    899 
    900 
    901 
    902  <td style="vertical-align: top;">
    903      
    904      
    905      
    906      
    907      
    908      
    909       <p><a name="bc_p_b"></a><b>bc_p_b</b></p>
    910 
    911 
    912 
    913 
    914 
    915 
    916  </td>
    917 
    918 
    919 
    920 
    921 
    922 
    923 
    924       <td style="vertical-align: top;">C * 20</td>
    925 
    926 
    927 
    928 
    929 
    930 
    931  <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
    932 
    933 
    934 
    935 
    936 
    937 
    938 
    939       <td style="vertical-align: top;">
    940      
    941      
    942      
    943      
    944      
    945      
    946       <p style="font-style: normal;">Bottom boundary condition of the
    947 perturbation pressure.&nbsp; </p>
    948 
    949 
    950 
    951 
    952 
    953 
    954  
    955      
    956      
    957      
    958      
    959      
    960      
    961       <p>Allowed values
    962 are <span style="font-style: italic;">'dirichlet'</span>,
    963       <span style="font-style: italic;">'neumann'</span>
    964 and <span style="font-style: italic;">'neumann+inhomo'</span>.&nbsp;
    965       <span style="font-style: italic;">'dirichlet'</span>
    966 sets
    967 p(k=0)=0.0,&nbsp; <span style="font-style: italic;">'neumann'</span>
    968 sets p(k=0)=p(k=1). <span style="font-style: italic;">'neumann+inhomo'</span>
    969 corresponds to an extended Neumann boundary condition where heat flux
    970 or temperature inhomogeneities near the
    971 surface (pt(k=1))&nbsp; are additionally regarded (see Shen and
    972 LeClerc
    973 (1995, Q.J.R. Meteorol. Soc.,
    974 1209)). This condition is only permitted with the Prandtl-layer
    975 switched on (<a href="#prandtl_layer">prandtl_layer</a>),
    976 otherwise the run is terminated.&nbsp; </p>
    977 
    978 
    979 
    980 
    981 
    982 
    983  
    984      
    985      
    986      
    987      
    988      
    989      
    990       <p>Since
    991 at the bottom boundary of the model the vertical
    992 velocity
    993 disappears (w(k=0) = 0.0), the consistent Neumann condition (<span style="font-style: italic;">'neumann'</span> or <span style="font-style: italic;">'neumann+inhomo'</span>)
    994 dp/dz = 0 should
    995 be used, which leaves the vertical component w unchanged when the
    996 pressure solver is applied. Simultaneous use of the Neumann boundary
    997 conditions both at the bottom and at the top boundary (<a href="#bc_p_t">bc_p_t</a>)
    998 usually yields no consistent solution for the perturbation pressure and
    999 should be avoided.</p>
    1000 
    1001 
    1002 
    1003 
    1004 
    1005 
    1006  </td>
    1007 
    1008 
    1009 
    1010 
    1011 
    1012 
    1013  </tr>
    1014 
    1015 
    1016 
    1017 
    1018 
    1019 
    1020  <tr>
    1021 
    1022 
    1023 
    1024 
    1025 
    1026 
    1027  <td style="vertical-align: top;">
    1028      
    1029      
    1030      
    1031      
    1032      
    1033      
    1034       <p><a name="bc_p_t"></a><b>bc_p_t</b></p>
    1035 
    1036 
    1037 
    1038 
    1039 
    1040 
    1041 
    1042       </td>
    1043 
    1044 
    1045 
    1046 
    1047 
    1048 
    1049  <td style="vertical-align: top;">C * 20</td>
    1050 
    1051 
    1052 
    1053 
    1054 
    1055 
    1056 
    1057       <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    1058 
    1059 
    1060 
    1061 
    1062 
    1063 
    1064 
    1065       <td style="vertical-align: top;">
    1066      
    1067      
    1068      
    1069      
    1070      
    1071      
    1072       <p style="font-style: normal;">Top boundary condition of the
    1073 perturbation pressure.&nbsp; </p>
    1074 
    1075 
    1076 
    1077 
    1078 
    1079 
    1080  
    1081      
    1082      
    1083      
    1084      
    1085      
    1086      
    1087       <p style="font-style: normal;">Allowed values are <span style="font-style: italic;">'dirichlet'</span>
    1088 (p(k=nz+1)= 0.0) or <span style="font-style: italic;">'neumann'</span>
    1089 (p(k=nz+1)=p(k=nz)).&nbsp; </p>
    1090 
    1091 
    1092 
    1093 
    1094 
    1095 
    1096  
    1097      
    1098      
    1099      
    1100      
    1101      
    1102      
    1103       <p>Simultaneous use
    1104 of Neumann boundary conditions both at the
    1105 top and bottom boundary (<a href="#bc_p_b">bc_p_b</a>)
    1106 usually yields no consistent solution for the perturbation pressure and
    1107 should be avoided. Since at the bottom boundary the Neumann
    1108 condition&nbsp; is a good choice (see <a href="#bc_p_b">bc_p_b</a>),
    1109 a Dirichlet condition should be set at the top boundary.</p>
    1110 
    1111 
    1112 
    1113 
    1114 
    1115 
    1116  </td>
    1117 
    1118 
    1119 
    1120 
    1121 
    1122 
    1123 
    1124     </tr>
    1125 
    1126 
    1127 
    1128 
    1129 
    1130 
    1131  <tr>
    1132 
    1133 
    1134 
    1135 
    1136 
    1137 
    1138  <td style="vertical-align: top;">
    1139      
    1140      
    1141      
    1142      
    1143      
    1144      
    1145       <p><a name="bc_pt_b"></a><b>bc_pt_b</b></p>
    1146 
    1147 
    1148 
    1149 
    1150 
    1151 
    1152 
    1153       </td>
    1154 
    1155 
    1156 
    1157 
    1158 
    1159 
    1160  <td style="vertical-align: top;">C*20</td>
    1161 
    1162 
    1163 
    1164 
    1165 
    1166 
    1167 
    1168       <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    1169 
    1170 
    1171 
    1172 
    1173 
    1174 
    1175 
    1176       <td style="vertical-align: top;">
    1177      
    1178      
    1179      
    1180      
    1181      
    1182      
    1183       <p style="font-style: normal;">Bottom boundary condition of the
    1184 potential temperature.&nbsp; </p>
    1185 
    1186 
    1187 
    1188 
    1189 
    1190 
    1191  
    1192      
    1193      
    1194      
    1195      
    1196      
    1197      
    1198       <p>Allowed values
    1199 are <span style="font-style: italic;">'dirichlet'</span>
    1200 (pt(k=0) = const. = <a href="#pt_surface">pt_surface</a>
    1201 + <a href="#pt_surface_initial_change">pt_surface_initial_change</a>;
    1202 the user may change this value during the run using user-defined code)
    1203 and <span style="font-style: italic;">'neumann'</span>
    1204 (pt(k=0)=pt(k=1)).&nbsp; <br>
    1205 
    1206 
    1207 
    1208 
    1209 
    1210 
    1211 
    1212 When a constant surface sensible heat flux is used (<a href="#surface_heatflux">surface_heatflux</a>), <b>bc_pt_b</b>
    1213 = <span style="font-style: italic;">'neumann'</span>
    1214 must be used, because otherwise the resolved scale may contribute to
    1215 the surface flux so that a constant value cannot be guaranteed.</p>
    1216 
    1217 
    1218 
    1219 
    1220 
    1221 
    1222      
    1223      
    1224      
    1225      
    1226      
    1227      
    1228       <p>In the <a href="chapter_3.8.html">coupled</a> 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.</p>
    1229 
    1230 
    1231 
    1232 
    1233 
    1234 
    1235 
    1236       </td>
    1237 
    1238 
    1239 
    1240 
    1241 
    1242 
    1243  </tr>
    1244 
    1245 
    1246 
    1247 
    1248 
    1249 
    1250  <tr>
    1251 
    1252 
    1253 
    1254 
    1255 
    1256 
    1257  <td style="vertical-align: top;">
    1258      
    1259      
    1260      
    1261      
    1262      
    1263      
    1264       <p><a name="pc_pt_t"></a><b>bc_pt_t</b></p>
    1265 
    1266 
    1267 
    1268 
    1269 
    1270 
    1271 
    1272       </td>
    1273 
    1274 
    1275 
    1276 
    1277 
    1278 
    1279  <td style="vertical-align: top;">C * 20</td>
    1280 
    1281 
    1282 
    1283 
    1284 
    1285 
    1286 
    1287       <td style="vertical-align: top;"><span style="font-style: italic;">'initial_ gradient'</span></td>
    1288 
    1289 
    1290 
    1291 
    1292 
    1293 
    1294 
    1295       <td style="vertical-align: top;">
    1296      
    1297      
    1298      
    1299      
    1300      
    1301      
    1302       <p style="font-style: normal;">Top boundary condition of the
    1303 potential temperature.&nbsp; </p>
    1304 
    1305 
    1306 
    1307 
    1308 
    1309 
    1310  
    1311      
    1312      
    1313      
    1314      
    1315      
    1316      
    1317       <p>Allowed are the
    1318 values <span style="font-style: italic;">'dirichlet' </span>(pt(k=nz+1)
    1319 does not change during the run), <span style="font-style: italic;">'neumann'</span>
    1320 (pt(k=nz+1)=pt(k=nz)), and <span style="font-style: italic;">'initial_gradient'</span>.
    1321 With the 'initial_gradient'-condition the value of the temperature
    1322 gradient at the top is
    1323 calculated from the initial
    1324 temperature profile (see <a href="#pt_surface">pt_surface</a>,
    1325       <a href="#pt_vertical_gradient">pt_vertical_gradient</a>)
    1326 by bc_pt_t_val = (pt_init(k=nz+1) -
    1327 pt_init(k=nz)) / dzu(nz+1).<br>
    1328 
    1329 
    1330 
    1331 
    1332 
    1333 
    1334 
    1335 Using this value (assumed constant during the
    1336 run) the temperature boundary values are calculated as&nbsp; </p>
    1337 
    1338 
    1339 
    1340 
    1341 
    1342 
    1343 
    1344      
    1345      
    1346      
    1347      
    1348      
    1349      
    1350       <ul>
    1351 
    1352 
    1353 
    1354 
    1355 
    1356 
    1357  
    1358        
    1359        
    1360        
    1361        
    1362        
    1363        
    1364         <p style="font-style: normal;">pt(k=nz+1) =
    1365 pt(k=nz) +
    1366 bc_pt_t_val * dzu(nz+1)</p>
    1367 
    1368 
    1369 
    1370 
    1371 
    1372 
    1373  
    1374      
    1375      
    1376      
    1377      
    1378      
    1379      
    1380       </ul>
    1381 
    1382 
    1383 
    1384 
    1385 
    1386 
    1387  
    1388      
    1389      
    1390      
    1391      
    1392      
    1393      
    1394       <p style="font-style: normal;">(up to k=nz the prognostic
    1395 equation for the temperature is solved).<br>
    1396 
    1397 
    1398 
    1399 
    1400 
    1401 
    1402 
    1403 When a constant sensible heat flux is used at the top boundary (<a href="chapter_4.1.html#top_heatflux">top_heatflux</a>),
    1404       <b>bc_pt_t</b> = <span style="font-style: italic;">'neumann'</span>
    1405 must be used, because otherwise the resolved scale may contribute to
    1406 the top flux so that a constant value cannot be guaranteed.</p>
    1407 
    1408 
    1409 
    1410 
    1411 
    1412 
    1413  </td>
    1414 
    1415 
    1416 
    1417 
    1418 
    1419 
    1420 
    1421     </tr>
    1422 
    1423 
    1424 
    1425 
    1426 
    1427 
    1428  <tr>
    1429 
    1430 
    1431 
    1432 
    1433 
    1434 
    1435  <td style="vertical-align: top;">
    1436      
    1437      
    1438      
    1439      
    1440      
    1441      
    1442       <p><a name="bc_q_b"></a><b>bc_q_b</b></p>
    1443 
    1444 
    1445 
    1446 
    1447 
    1448 
    1449 
    1450       </td>
    1451 
    1452 
    1453 
    1454 
    1455 
    1456 
    1457  <td style="vertical-align: top;">C * 20</td>
    1458 
    1459 
    1460 
    1461 
    1462 
    1463 
    1464 
    1465       <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    1466 
    1467 
    1468 
    1469 
    1470 
    1471 
    1472 
    1473       <td style="vertical-align: top;">
    1474      
    1475      
    1476      
    1477      
    1478      
    1479      
    1480       <p style="font-style: normal;">Bottom boundary condition of the
    1481 specific humidity / total water content.&nbsp; </p>
    1482 
    1483 
    1484 
    1485 
    1486 
    1487 
    1488  
    1489      
    1490      
    1491      
    1492      
    1493      
    1494      
    1495       <p>Allowed
    1496 values are <span style="font-style: italic;">'dirichlet'</span>
    1497 (q(k=0) = const. = <a href="#q_surface">q_surface</a>
    1498 + <a href="#q_surface_initial_change">q_surface_initial_change</a>;
    1499 the user may change this value during the run using user-defined code)
    1500 and <span style="font-style: italic;">'neumann'</span>
    1501 (q(k=0)=q(k=1)).&nbsp; <br>
    1502 
    1503 
    1504 
    1505 
    1506 
    1507 
    1508 
    1509 When a constant surface latent heat flux is used (<a href="#surface_waterflux">surface_waterflux</a>), <b>bc_q_b</b>
    1510 = <span style="font-style: italic;">'neumann'</span>
    1511 must be used, because otherwise the resolved scale may contribute to
    1512 the surface flux so that a constant value cannot be guaranteed.</p>
    1513 
    1514 
    1515 
    1516 
    1517 
    1518 
    1519 
    1520       </td>
    1521 
    1522 
    1523 
    1524 
    1525 
    1526 
    1527  </tr>
    1528 
    1529 
    1530 
    1531 
    1532 
    1533 
    1534  <tr>
    1535 
    1536 
    1537 
    1538 
    1539 
    1540 
    1541  <td style="vertical-align: top;">
    1542      
    1543      
    1544      
    1545      
    1546      
    1547      
    1548       <p><a name="bc_q_t"></a><b>bc_q_t</b></p>
    1549 
    1550 
    1551 
    1552 
    1553 
    1554 
    1555 
    1556       </td>
    1557 
    1558 
    1559 
    1560 
    1561 
    1562 
    1563  <td style="vertical-align: top;"><span style="font-style: italic;">C
    1564 * 20</span></td>
    1565 
    1566 
    1567 
    1568 
    1569 
    1570 
    1571  <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
    1572 
    1573 
    1574 
    1575 
    1576 
    1577 
    1578 
    1579       <td style="vertical-align: top;">
    1580      
    1581      
    1582      
    1583      
    1584      
    1585      
    1586       <p style="font-style: normal;">Top boundary condition of the
    1587 specific humidity / total water content.&nbsp; </p>
    1588 
    1589 
    1590 
    1591 
    1592 
    1593 
    1594  
    1595      
    1596      
    1597      
    1598      
    1599      
    1600      
    1601       <p>Allowed
    1602 are the values <span style="font-style: italic;">'dirichlet'</span>
    1603 (q(k=nz) and q(k=nz+1) do
    1604 not change during the run) and <span style="font-style: italic;">'neumann'</span>.
    1605 With the Neumann boundary
    1606 condition the value of the humidity gradient at the top is calculated
    1607 from the
    1608 initial humidity profile (see <a href="#q_surface">q_surface</a>,
    1609       <a href="#q_vertical_gradient">q_vertical_gradient</a>)
    1610 by: bc_q_t_val = ( q_init(k=nz) - q_init(k=nz-1)) / dzu(nz).<br>
    1611 
    1612 
    1613 
    1614 
    1615 
    1616 
    1617 
    1618 Using this value (assumed constant during the run) the humidity
    1619 boundary values
    1620 are calculated as&nbsp; </p>
    1621 
    1622 
    1623 
    1624 
    1625 
    1626 
    1627  
    1628      
    1629      
    1630      
    1631      
    1632      
    1633      
    1634       <ul>
    1635 
    1636 
    1637 
    1638 
    1639 
    1640 
    1641  
    1642        
    1643        
    1644        
    1645        
    1646        
    1647        
    1648         <p style="font-style: normal;">q(k=nz+1) =q(k=nz) +
    1649 bc_q_t_val * dzu(nz+1)</p>
    1650 
    1651 
    1652 
    1653 
    1654 
    1655 
    1656  
    1657      
    1658      
    1659      
    1660      
    1661      
    1662      
    1663       </ul>
    1664 
    1665 
    1666 
    1667 
    1668 
    1669 
    1670  
    1671      
    1672      
    1673      
    1674      
    1675      
    1676      
    1677       <p style="font-style: normal;">(up tp k=nz the prognostic
    1678 equation for q is solved). </p>
    1679 
    1680 
    1681 
    1682 
    1683 
    1684 
    1685  </td>
    1686 
    1687 
    1688 
    1689 
    1690 
    1691 
    1692  </tr>
    1693 
    1694 
    1695 
    1696 
    1697 
    1698 
    1699  <tr>
    1700 
    1701 
    1702 
    1703 
    1704 
    1705 
    1706 
    1707       <td style="vertical-align: top;">
    1708      
    1709      
    1710      
    1711      
    1712      
    1713      
    1714       <p><a name="bc_s_b"></a><b>bc_s_b</b></p>
    1715 
    1716 
    1717 
    1718 
    1719 
    1720 
    1721  </td>
    1722 
    1723 
    1724 
    1725 
    1726 
    1727 
    1728 
    1729       <td style="vertical-align: top;">C * 20</td>
    1730 
    1731 
    1732 
    1733 
    1734 
    1735 
    1736  <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    1737 
    1738 
    1739 
    1740 
    1741 
    1742 
    1743 
    1744       <td style="vertical-align: top;">
    1745      
    1746      
    1747      
    1748      
    1749      
    1750      
    1751       <p style="font-style: normal;">Bottom boundary condition of the
    1752 scalar concentration.&nbsp; </p>
    1753 
    1754 
    1755 
    1756 
    1757 
    1758 
    1759  
    1760      
    1761      
    1762      
    1763      
    1764      
    1765      
    1766       <p>Allowed values
    1767 are <span style="font-style: italic;">'dirichlet'</span>
    1768 (s(k=0) = const. = <a href="#s_surface">s_surface</a>
    1769 + <a href="#s_surface_initial_change">s_surface_initial_change</a>;
    1770 the user may change this value during the run using user-defined code)
    1771 and <span style="font-style: italic;">'neumann'</span>
    1772 (s(k=0) =
    1773 s(k=1)).&nbsp; <br>
    1774 
    1775 
    1776 
    1777 
    1778 
    1779 
    1780 
    1781 When a constant surface concentration flux is used (<a href="#surface_scalarflux">surface_scalarflux</a>), <b>bc_s_b</b>
    1782 = <span style="font-style: italic;">'neumann'</span>
    1783 must be used, because otherwise the resolved scale may contribute to
    1784 the surface flux so that a constant value cannot be guaranteed.</p>
    1785 
    1786 
    1787 
    1788 
    1789 
    1790 
    1791 
    1792       </td>
    1793 
    1794 
    1795 
    1796 
    1797 
    1798 
    1799  </tr>
    1800 
    1801 
    1802 
    1803 
    1804 
    1805 
    1806  <tr>
    1807 
    1808 
    1809 
    1810 
    1811 
    1812 
    1813  <td style="vertical-align: top;">
    1814      
    1815      
    1816      
    1817      
    1818      
    1819      
    1820       <p><a name="bc_s_t"></a><b>bc_s_t</b></p>
    1821 
    1822 
    1823 
    1824 
    1825 
    1826 
    1827 
    1828       </td>
    1829 
    1830 
    1831 
    1832 
    1833 
    1834 
    1835  <td style="vertical-align: top;">C * 20</td>
    1836 
    1837 
    1838 
    1839 
    1840 
    1841 
    1842 
    1843       <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
    1844 
    1845 
    1846 
    1847 
    1848 
    1849 
    1850 
    1851       <td style="vertical-align: top;">
    1852      
    1853      
    1854      
    1855      
    1856      
    1857      
    1858       <p style="font-style: normal;">Top boundary condition of the
    1859 scalar concentration.&nbsp; </p>
    1860 
    1861 
    1862 
    1863 
    1864 
    1865 
    1866  
    1867      
    1868      
    1869      
    1870      
    1871      
    1872      
    1873       <p>Allowed are the
    1874 values <span style="font-style: italic;">'dirichlet'</span>
    1875 (s(k=nz) and s(k=nz+1) do
    1876 not change during the run) and <span style="font-style: italic;">'neumann'</span>.
    1877 With the Neumann boundary
    1878 condition the value of the scalar concentration gradient at the top is
    1879 calculated
    1880 from the initial scalar concentration profile (see <a href="#s_surface">s_surface</a>, <a href="#s_vertical_gradient">s_vertical_gradient</a>)
    1881 by: bc_s_t_val = (s_init(k=nz) - s_init(k=nz-1)) / dzu(nz).<br>
    1882 
    1883 
    1884 
    1885 
    1886 
    1887 
    1888 
    1889 Using this value (assumed constant during the run) the concentration
    1890 boundary values
    1891 are calculated as </p>
    1892 
    1893 
    1894 
    1895 
    1896 
    1897 
    1898  
    1899      
    1900      
    1901      
    1902      
    1903      
    1904      
    1905       <ul>
    1906 
    1907 
    1908 
    1909 
    1910 
    1911 
    1912  
    1913        
    1914        
    1915        
    1916        
    1917        
    1918        
    1919         <p style="font-style: normal;">s(k=nz+1) = s(k=nz) +
    1920 bc_s_t_val * dzu(nz+1)</p>
    1921 
    1922 
    1923 
    1924 
    1925 
    1926 
    1927  
    1928      
    1929      
    1930      
    1931      
    1932      
    1933      
    1934       </ul>
    1935 
    1936 
    1937 
    1938 
    1939 
    1940 
    1941  
    1942      
    1943      
    1944      
    1945      
    1946      
    1947      
    1948       <p style="font-style: normal;">(up to k=nz the prognostic
    1949 equation for the scalar concentration is
    1950 solved).</p>
    1951 
    1952 
    1953 
    1954 
    1955 
    1956 
    1957  </td>
    1958 
    1959 
    1960 
    1961 
    1962 
    1963 
    1964  </tr>
    1965 
    1966 
    1967 
    1968 
    1969 
    1970 
    1971  <tr>
    1972 
    1973 
    1974 
    1975 
    1976 
    1977 
    1978       <td style="vertical-align: top;"><a name="bc_sa_t"></a><span style="font-weight: bold;">bc_sa_t</span></td>
    1979 
    1980 
    1981 
    1982 
    1983 
    1984 
    1985       <td style="vertical-align: top;">C * 20</td>
    1986 
    1987 
    1988 
    1989 
    1990 
    1991 
    1992       <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
    1993 
    1994 
    1995 
    1996 
    1997 
    1998 
    1999       <td style="vertical-align: top;">
    2000      
    2001      
    2002      
    2003      
    2004      
    2005      
    2006       <p style="font-style: normal;">Top boundary condition of the salinity.&nbsp; </p>
    2007 
    2008 
    2009 
    2010 
    2011 
    2012 
    2013  
    2014      
    2015      
    2016      
    2017      
    2018      
    2019      
    2020       <p>This parameter only comes into effect for ocean runs (see parameter <a href="#ocean">ocean</a>).</p>
    2021 
    2022 
    2023 
    2024 
    2025 
    2026 
    2027      
    2028      
    2029      
    2030      
    2031      
    2032      
    2033       <p style="font-style: normal;">Allowed are the
    2034 values <span style="font-style: italic;">'dirichlet' </span>(sa(k=nz+1)
    2035 does not change during the run) and <span style="font-style: italic;">'neumann'</span>
    2036 (sa(k=nz+1)=sa(k=nz))<span style="font-style: italic;"></span>.&nbsp;<br>
    2037 
    2038 
    2039 
    2040 
    2041 
    2042 
    2043       <br>
    2044 
    2045 
    2046 
    2047 
    2048 
    2049 
    2050 
    2051 When a constant salinity flux is used at the top boundary (<a href="chapter_4.1.html#top_salinityflux">top_salinityflux</a>),
    2052       <b>bc_sa_t</b> = <span style="font-style: italic;">'neumann'</span>
    2053 must be used, because otherwise the resolved scale may contribute to
    2054 the top flux so that a constant value cannot be guaranteed.</p>
    2055 
    2056 
    2057 
    2058 
    2059 
    2060 
    2061       </td>
    2062 
    2063 
    2064 
    2065 
    2066 
    2067 
    2068     </tr>
    2069 
    2070 
    2071 
    2072 
    2073 
    2074 
    2075     <tr>
    2076 
    2077 
    2078 
    2079 
    2080 
    2081 
    2082  <td style="vertical-align: top;">
    2083      
    2084      
    2085      
    2086      
    2087      
    2088      
    2089       <p><a name="bc_uv_b"></a><b>bc_uv_b</b></p>
    2090 
    2091 
    2092 
    2093 
    2094 
    2095 
    2096 
    2097       </td>
    2098 
    2099 
    2100 
    2101 
    2102 
    2103 
    2104  <td style="vertical-align: top;">C * 20</td>
    2105 
    2106 
    2107 
    2108 
    2109 
    2110 
    2111 
    2112       <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    2113 
    2114 
    2115 
    2116 
    2117 
    2118 
    2119 
    2120       <td style="vertical-align: top;">
    2121      
    2122      
    2123      
    2124      
    2125      
    2126      
    2127       <p style="font-style: normal;">Bottom boundary condition of the
    2128 horizontal velocity components u and v.&nbsp; </p>
    2129 
    2130 
    2131 
    2132 
    2133 
    2134 
    2135  
    2136      
    2137      
    2138      
    2139      
    2140      
    2141      
    2142       <p>Allowed
    2143 values are <span style="font-style: italic;">'dirichlet' </span>and
    2144       <span style="font-style: italic;">'neumann'</span>. <b>bc_uv_b</b>
    2145 = <span style="font-style: italic;">'dirichlet'</span>
    2146 yields the
    2147 no-slip condition with u=v=0 at the bottom. Due to the staggered grid
    2148 u(k=0) and v(k=0) are located at z = - 0,5 * <a href="#dz">dz</a>
    2149 (below the bottom), while u(k=1) and v(k=1) are located at z = +0,5 *
    2150 dz. u=v=0 at the bottom is guaranteed using mirror boundary
    2151 condition:&nbsp; </p>
    2152 
    2153 
    2154 
    2155 
    2156 
    2157 
    2158  
    2159      
    2160      
    2161      
    2162      
    2163      
    2164      
    2165       <ul>
    2166 
    2167 
    2168 
    2169 
    2170 
    2171 
    2172  
    2173        
    2174        
    2175        
    2176        
    2177        
    2178        
    2179         <p style="font-style: normal;">u(k=0) = - u(k=1) and v(k=0) = -
    2180 v(k=1)</p>
    2181 
    2182 
    2183 
    2184 
    2185 
    2186 
    2187  
    2188      
    2189      
    2190      
    2191      
    2192      
    2193      
    2194       </ul>
    2195 
    2196 
    2197 
    2198 
    2199 
    2200 
    2201  
    2202      
    2203      
    2204      
    2205      
    2206      
    2207      
    2208       <p style="font-style: normal;">The
    2209 Neumann boundary condition
    2210 yields the free-slip condition with u(k=0) = u(k=1) and v(k=0) =
    2211 v(k=1).
    2212 With Prandtl - layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>), the free-slip condition is not
    2213 allowed (otherwise the run will be terminated)<font color="#000000">.</font></p>
    2214 
    2215 
    2216 
    2217 
    2218 
    2219 
    2220 
    2221       </td>
    2222 
    2223 
    2224 
    2225 
    2226 
    2227 
    2228  </tr>
    2229 
    2230 
    2231 
    2232 
    2233 
    2234 
    2235  <tr>
    2236 
    2237 
    2238 
    2239 
    2240 
    2241 
    2242  <td style="vertical-align: top;">
    2243      
    2244      
    2245      
    2246      
    2247      
    2248      
    2249       <p><a name="bc_uv_t"></a><b>bc_uv_t</b></p>
    2250 
    2251 
    2252 
    2253 
    2254 
    2255 
    2256 
    2257       </td>
    2258 
    2259 
    2260 
    2261 
    2262 
    2263 
    2264  <td style="vertical-align: top;">C * 20</td>
    2265 
    2266 
    2267 
    2268 
    2269 
    2270 
    2271 
    2272       <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
    2273 
    2274 
    2275 
    2276 
    2277 
    2278 
    2279 
    2280       <td style="vertical-align: top;">
    2281      
    2282      
    2283      
    2284      
    2285      
    2286      
    2287       <p style="font-style: normal;">Top boundary condition of the
    2288 horizontal velocity components u and v.&nbsp; </p>
    2289 
    2290 
    2291 
    2292 
    2293 
    2294 
    2295  
    2296      
    2297      
    2298      
    2299      
    2300      
    2301      
    2302       <p>Allowed
    2303 values are <span style="font-style: italic;">'dirichlet'</span>, <span style="font-style: italic;">'dirichlet_0'</span>
    2304 and <span style="font-style: italic;">'neumann'</span>.
    2305 The
    2306 Dirichlet condition yields u(k=nz+1) = ug(nz+1) and v(k=nz+1) =
    2307 vg(nz+1),
    2308 Neumann condition yields the free-slip condition with u(k=nz+1) =
    2309 u(k=nz) and v(k=nz+1) = v(k=nz) (up to k=nz the prognostic equations
    2310 for the velocities are solved). The special condition&nbsp;<span style="font-style: italic;">'dirichlet_0'</span> can be used for channel flow, it yields the no-slip condition u(k=nz+1) = ug(nz+1) = 0 and v(k=nz+1) =
    2311 vg(nz+1) = 0.</p>
    2312 
    2313 
    2314 
    2315 
    2316 
    2317 
    2318      
    2319      
    2320      
    2321      
    2322      
    2323      
    2324       <p>In the <a href="chapter_3.8.html">coupled</a> 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.</p>
    2325 
    2326 
    2327 
    2328 
    2329 
    2330 
    2331  </td>
    2332 
    2333 
    2334 
    2335 
    2336 
    2337 
    2338  </tr>
    2339 
    2340 
    2341 
    2342 
    2343 
    2344 
    2345  <tr>
    2346 
    2347 
    2348 
    2349 
    2350 
    2351 
    2352       <td style="vertical-align: top;"><a name="bottom_salinityflux"></a><span style="font-weight: bold;">bottom_salinityflux</span></td>
    2353 
    2354 
    2355 
    2356 
    2357 
    2358 
    2359       <td style="vertical-align: top;">R</td>
    2360 
    2361 
    2362 
    2363 
    2364 
    2365 
    2366       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    2367 
    2368 
    2369 
    2370 
    2371 
    2372 
    2373       <td style="vertical-align: top;">
    2374      
    2375      
    2376      
    2377      
    2378      
    2379      
    2380       <p>Kinematic salinity flux near the surface (in psu m/s).&nbsp;</p>
    2381 
    2382 
    2383 
    2384 
    2385 
    2386 
    2387 This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
    2388      
    2389      
    2390      
    2391      
    2392      
    2393      
    2394       <p>The
    2395 respective salinity flux value is used
    2396 as bottom (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
    2397 condition must be used for the salinity, which is currently the only available condition.<br>
    2398 
    2399 
    2400 
    2401 
    2402 
    2403 
    2404  </p>
    2405 
    2406 
    2407 
    2408 
    2409 
    2410 
    2411  </td>
    2412 
    2413 
    2414 
    2415 
    2416 
    2417 
    2418     </tr>
    2419 
    2420 
    2421 
    2422 
    2423 
    2424 
    2425     <tr>
    2426 
    2427 
    2428 
    2429 
    2430 
    2431 
    2432 
    2433       <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_height"></a>building_height</span></td>
    2434 
    2435 
    2436 
    2437 
    2438 
    2439 
    2440 
    2441       <td style="vertical-align: top;">R</td>
    2442 
    2443 
    2444 
    2445 
    2446 
    2447 
    2448  <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
    2449 
    2450 
    2451 
    2452 
    2453 
    2454 
    2455  <td>Height
    2456 of a single building in m.<br>
    2457 
    2458 
    2459 
    2460 
    2461 
    2462 
    2463  <br>
    2464 
    2465 
    2466 
    2467 
    2468 
    2469 
    2470  <span style="font-weight: bold;">building_height</span> must
    2471 be less than the height of the model domain. This parameter requires
    2472 the use of&nbsp;<a href="#topography">topography</a>
    2473 = <span style="font-style: italic;">'single_building'</span>.</td>
    2474 
    2475 
    2476 
    2477 
    2478 
    2479 
    2480 
    2481     </tr>
    2482 
    2483 
    2484 
    2485 
    2486 
    2487 
    2488  <tr>
    2489 
    2490 
    2491 
    2492 
    2493 
    2494 
    2495  <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_x"></a>building_length_x</span></td>
    2496 
    2497 
    2498 
    2499 
    2500 
    2501 
    2502 
    2503       <td style="vertical-align: top;">R</td>
    2504 
    2505 
    2506 
    2507 
    2508 
    2509 
    2510  <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
    2511 
    2512 
    2513 
    2514 
    2515 
    2516 
    2517  <td><span style="font-style: italic;"></span>Width of a single
    2518 building in m.<br>
    2519 
    2520 
    2521 
    2522 
    2523 
    2524 
    2525  <br>
    2526 
    2527 
    2528 
    2529 
    2530 
    2531 
    2532 
    2533 Currently, <span style="font-weight: bold;">building_length_x</span>
    2534 must be at least <span style="font-style: italic;">3
    2535 *&nbsp;</span><a style="font-style: italic;" href="#dx">dx</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="#nx">nx</a><span style="font-style: italic;"> - 1 ) </span><span style="font-style: italic;"> * <a href="#dx">dx</a>
    2536       </span><span style="font-style: italic;">- <a href="#building_wall_left">building_wall_left</a></span>.
    2537 This parameter requires the use of&nbsp;<a href="#topography">topography</a>
    2538 = <span style="font-style: italic;">'single_building'</span>.</td>
    2539 
    2540 
    2541 
    2542 
    2543 
    2544 
    2545 
    2546     </tr>
    2547 
    2548 
    2549 
    2550 
    2551 
    2552 
    2553  <tr>
    2554 
    2555 
    2556 
    2557 
    2558 
    2559 
    2560  <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_y"></a>building_length_y</span></td>
    2561 
    2562 
    2563 
    2564 
    2565 
    2566 
    2567 
    2568       <td style="vertical-align: top;">R</td>
    2569 
    2570 
    2571 
    2572 
    2573 
    2574 
    2575  <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
    2576 
    2577 
    2578 
    2579 
    2580 
    2581 
    2582  <td>Depth
    2583 of a single building in m.<br>
    2584 
    2585 
    2586 
    2587 
    2588 
    2589 
    2590  <br>
    2591 
    2592 
    2593 
    2594 
    2595 
    2596 
    2597 
    2598 Currently, <span style="font-weight: bold;">building_length_y</span>
    2599 must be at least <span style="font-style: italic;">3
    2600 *&nbsp;</span><a style="font-style: italic;" href="#dy">dy</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="#ny">ny</a><span style="font-style: italic;"> - 1 )&nbsp;</span><span style="font-style: italic;"> * <a href="#dy">dy</a></span><span style="font-style: italic;"> - <a href="#building_wall_south">building_wall_south</a></span>. This parameter requires
    2601 the use of&nbsp;<a href="#topography">topography</a>
    2602 = <span style="font-style: italic;">'single_building'</span>.</td>
    2603 
    2604 
    2605 
    2606 
    2607 
    2608 
    2609 
    2610     </tr>
    2611 
    2612 
    2613 
    2614 
    2615 
    2616 
    2617  <tr>
    2618 
    2619 
    2620 
    2621 
    2622 
    2623 
    2624  <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_left"></a>building_wall_left</span></td>
    2625 
    2626 
    2627 
    2628 
    2629 
    2630 
    2631 
    2632       <td style="vertical-align: top;">R</td>
    2633 
    2634 
    2635 
    2636 
    2637 
    2638 
    2639  <td style="vertical-align: top;"><span style="font-style: italic;">building centered in x-direction</span></td>
    2640 
    2641 
    2642 
    2643 
    2644 
    2645 
    2646 
    2647       <td>x-coordinate of the left building wall (distance between the
    2648 left building wall and the left border of the model domain) in m.<br>
    2649 
    2650 
    2651 
    2652 
    2653 
    2654 
    2655 
    2656       <br>
    2657 
    2658 
    2659 
    2660 
    2661 
    2662 
    2663 
    2664 Currently, <span style="font-weight: bold;">building_wall_left</span>
    2665 must be at least <span style="font-style: italic;">1
    2666 *&nbsp;</span><a style="font-style: italic;" href="#dx">dx</a> and less than <span style="font-style: italic;">( <a href="#nx">nx</a>&nbsp;
    2667 - 1 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a></span>.
    2668 This parameter requires the use of&nbsp;<a href="#topography">topography</a>
    2669 = <span style="font-style: italic;">'single_building'</span>.<br>
    2670 
    2671 
    2672 
    2673 
    2674 
    2675 
    2676 
    2677       <br>
    2678 
    2679 
    2680 
    2681 
    2682 
    2683 
    2684 
    2685 The default value&nbsp;<span style="font-weight: bold;">building_wall_left</span>
    2686 = <span style="font-style: italic;">( ( <a href="#nx">nx</a>&nbsp;+
    2687 1 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a> ) / 2</span>
    2688 centers the building in x-direction.&nbsp;<font color="#000000">Due to the staggered grid the building will be displaced by -0.5 <a href="chapter_4.1.html#dx">dx</a> in x-direction and -0.5 <a href="chapter_4.1.html#dy">dy</a> in y-direction.</font> </td>
    2689 
    2690 
    2691 
    2692 
    2693 
    2694 
    2695  </tr>
    2696 
    2697 
    2698 
    2699 
    2700 
    2701 
    2702  <tr>
    2703 
    2704 
    2705 
    2706 
    2707 
    2708 
    2709 
    2710       <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_south"></a>building_wall_south</span></td>
    2711 
    2712 
    2713 
    2714 
    2715 
    2716 
    2717 
    2718       <td style="vertical-align: top;">R</td>
    2719 
    2720 
    2721 
    2722 
    2723 
    2724 
    2725  <td style="vertical-align: top;"><span style="font-style: italic;"></span><span style="font-style: italic;">building centered in y-direction</span></td>
    2726 
    2727 
    2728 
    2729 
    2730 
    2731 
    2732 
    2733       <td>y-coordinate of the South building wall (distance between the
    2734 South building wall and the South border of the model domain) in m.<br>
    2735 
    2736 
    2737 
    2738 
    2739 
    2740 
    2741 
    2742       <br>
    2743 
    2744 
    2745 
    2746 
    2747 
    2748 
    2749 
    2750 Currently, <span style="font-weight: bold;">building_wall_south</span>
    2751 must be at least <span style="font-style: italic;">1
    2752 *&nbsp;</span><a style="font-style: italic;" href="#dy">dy</a> and less than <span style="font-style: italic;">( <a href="#ny">ny</a>&nbsp;
    2753 - 1 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a></span>.
    2754 This parameter requires the use of&nbsp;<a href="#topography">topography</a>
    2755 = <span style="font-style: italic;">'single_building'</span>.<br>
    2756 
    2757 
    2758 
    2759 
    2760 
    2761 
    2762 
    2763       <br>
    2764 
    2765 
    2766 
    2767 
    2768 
    2769 
    2770 
    2771 The default value&nbsp;<span style="font-weight: bold;">building_wall_south</span>
    2772 = <span style="font-style: italic;">( ( <a href="#ny">ny</a>&nbsp;+
    2773 1 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a> ) / 2</span>
    2774 centers the building in y-direction.&nbsp;<font color="#000000">Due to the staggered grid the building will be displaced by -0.5 <a href="chapter_4.1.html#dx">dx</a> in x-direction and -0.5 <a href="chapter_4.1.html#dy">dy</a> in y-direction.</font> </td>
    2775 
    2776 
    2777 
    2778 
    2779 
    2780 
    2781  </tr>
    2782 
    2783 
    2784 
    2785 
    2786 
    2787 
    2788  <tr>
    2789 
    2790       <td style="vertical-align: top;"><a name="canopy_mode"></a><span style="font-weight: bold;">canopy_mode</span></td>
    2791 
    2792       <td style="vertical-align: top;">C * 20</td>
    2793 
    2794       <td style="vertical-align: top;"><span style="font-style: italic;">'block'</span></td>
    2795 
    2796       <td style="vertical-align: top;">Canopy mode.<br>
    2797 
    2798       <br>
    2799 
    2800       <font color="#000000">
    2801 Besides using the default value, that will create a horizontally
    2802 homogeneous plant canopy that extends over the total horizontal
    2803 extension of the model domain, the user may add code to the user
    2804 interface subroutine <a href="chapter_3.5.1.html#user_init_plant_canopy">user_init_plant_canopy</a>
    2805 to allow further canopy&nbsp;modes. <br>
    2806 
    2807       <br>
    2808 
    2809 The setting of <a href="#canopy_mode">canopy_mode</a> becomes only active, if&nbsp;<a href="#plant_canopy">plant_canopy</a> has been set <span style="font-style: italic;">.T.</span> and a non-zero <a href="#drag_coefficient">drag_coefficient</a> has been defined.</font></td>
    2810 
    2811     </tr>
    2812 
    2813     <tr><td style="font-weight: bold; vertical-align: top;"><a name="canyon_height"></a>canyon_height</td><td style="vertical-align: top;">R</td><td style="font-style: italic; vertical-align: top;">50.0</td><td>Street canyon height
    2814 in m.<br>
    2815 
    2816 
    2817 
    2818 
    2819 
    2820 
    2821  <br>
    2822 
    2823 
    2824 
    2825 
    2826 
    2827 
    2828  <span style="font-weight: bold;">canyon_height</span> must
    2829 be less than the height of the model domain. This parameter requires&nbsp;<a href="chapter_4.1.html#topography">topography</a>
    2830 = <span style="font-style: italic;">'single_street_canyon'</span>.</td></tr><tr><td style="font-weight: bold; vertical-align: top;"><a name="canyon_width_x"></a>canyon_width_x</td><td style="vertical-align: top;">R</td><td style="font-style: italic; vertical-align: top;">9999999.9</td><td>Street canyon width in x-direction in m.<br>
    2831 
    2832 
    2833 
    2834 
    2835 
    2836 
    2837  <br>
    2838 
    2839 
    2840 
    2841 
    2842 
    2843 
    2844 
    2845 Currently, <span style="font-weight: bold;">canyon_width_x</span>
    2846 must be at least <span style="font-style: italic;">3
    2847 *&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#dx">dx</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#nx">nx</a><span style="font-style: italic;"> - 1 ) </span><span style="font-style: italic;"> * <a href="chapter_4.1.html#dx">dx</a>
    2848       </span><span style="font-style: italic;">- <a href="chapter_4.1.html#canyon_wall_left">canyon_wall_left</a></span>.
    2849 This parameter requires&nbsp;<a href="chapter_4.1.html#topography">topography</a>
    2850 = <span style="font-style: italic;">'</span><span style="font-style: italic;">single_street_canyon</span><span style="font-style: italic;">'</span>. A non-default value implies a canyon orientation in y-direction.</td></tr><tr><td style="font-weight: bold; vertical-align: top;"><a name="canyon_width_y"></a>canyon_width_y</td><td style="vertical-align: top;">R</td><td style="font-style: italic; vertical-align: top;">9999999.9</td><td>Street canyon width in y-direction in m.<br>
    2851 
    2852 
    2853 
    2854 
    2855 
    2856 
    2857  <br>
    2858 
    2859 
    2860 
    2861 
    2862 
    2863 
    2864 
    2865 Currently, <span style="font-weight: bold;">canyon_width_y</span>
    2866 must be at least <span style="font-style: italic;">3
    2867 *&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#dy">dy</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#ny">ny</a><span style="font-style: italic;"> - 1 )&nbsp;</span><span style="font-style: italic;"> * <a href="chapter_4.1.html#dy">dy</a></span><span style="font-style: italic;"> - <a href="chapter_4.1.html#canyon_wall_south">canyon_wall_south</a></span>. This parameter requires&nbsp;<a href="chapter_4.1.html#topography">topography</a>
    2868 = <span style="font-style: italic;">'</span><span style="font-style: italic;">single_street_canyon</span>.&nbsp;A non-default value implies a canyon orientation in x-direction.</td></tr><tr><td style="font-weight: bold; vertical-align: top;"><a name="canyon_wall_left"></a>canyon_wall_left</td><td style="vertical-align: top;">R</td><td style="font-style: italic; vertical-align: top;"><span style="font-style: italic;">canyon centered in x-direction</span></td><td>x-coordinate of the left canyon wall (distance between the
    2869 left canyon wall and the left border of the model domain) in m.<br>
    2870 
    2871 
    2872 
    2873 
    2874 
    2875 
    2876 
    2877       <br>
    2878 
    2879 
    2880 
    2881 
    2882 
    2883 
    2884 
    2885 Currently, <span style="font-weight: bold;">canyon_wall_left</span>
    2886 must be at least <span style="font-style: italic;">1
    2887 *&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#dx">dx</a> and less than <span style="font-style: italic;">( <a href="chapter_4.1.html#nx">nx</a>&nbsp;
    2888 - 1 ) * <a href="chapter_4.1.html#dx">dx</a> -&nbsp; <a href="chapter_4.1.html#canyon_width_x">canyon_width_x</a></span>.
    2889 This parameter requires&nbsp;<a href="chapter_4.1.html#topography">topography</a>
    2890 = <span style="font-style: italic;">'</span><span style="font-style: italic;">single_street_canyon</span><span style="font-style: italic;">'</span>.<br>
    2891 
    2892 
    2893 
    2894 
    2895 
    2896 
    2897 
    2898       <br>
    2899 
    2900 
    2901 
    2902 
    2903 
    2904 
    2905 
    2906 The default value <span style="font-weight: bold;">canyon_wall_left</span>
    2907 = <span style="font-style: italic;">( ( <a href="chapter_4.1.html#nx">nx</a>&nbsp;+
    2908 1 ) * <a href="chapter_4.1.html#dx">dx</a> -&nbsp; <a href="chapter_4.1.html#canyon_width_x">canyon_width_x</a> ) / 2</span>
    2909 centers the canyon in x-direction.</td></tr><tr><td style="font-weight: bold; vertical-align: top;"><a name="canyon_wall_south"></a>canyon_wall_south</td><td style="vertical-align: top;">R</td><td style="font-style: italic; vertical-align: top;"><span style="font-style: italic;">canyon centered in y-direction</span></td><td>y-coordinate of the South canyon wall (distance between the
    2910 South canyon wall and the South border of the model domain) in m.<br>
    2911 
    2912 
    2913 
    2914 
    2915 
    2916 
    2917 
    2918       <br>
    2919 
    2920 
    2921 
    2922 
    2923 
    2924 
    2925 
    2926 Currently, <span style="font-weight: bold;">canyon_wall_south</span>
    2927 must be at least <span style="font-style: italic;">1
    2928 *&nbsp;</span><a style="font-style: italic;" href="chapter_4.1.html#dy">dy</a> and less than <span style="font-style: italic;">( <a href="chapter_4.1.html#ny">ny</a>&nbsp;
    2929 - 1 ) * <a href="chapter_4.1.html#dy">dy</a> -&nbsp; <a href="chapter_4.1.html#canyon_width_y">canyon_width_y</a></span>.
    2930 This parameter requires&nbsp;<a href="chapter_4.1.html#topography">topography</a>
    2931 = <span style="font-style: italic;">'</span><span style="font-style: italic;">single_street_canyon</span><span style="font-style: italic;">'</span>.<br>
    2932 
    2933 
    2934 
    2935 
    2936 
    2937 
    2938 
    2939       <br>
    2940 
    2941 
    2942 
    2943 
    2944 
    2945 
    2946 
    2947 The default value <span style="font-weight: bold;">canyon_wall_south</span>
    2948 = <span style="font-style: italic;">( ( <a href="chapter_4.1.html#ny">ny</a>&nbsp;+
    2949 1 ) * <a href="chapter_4.1.html#dy">dy</a> -&nbsp;&nbsp;</span><a href="chapter_4.1.html#building_length_y"><span style="font-style: italic;"></span></a><a style="font-style: italic;" href="chapter_4.1.html#canyon_width_y">canyon_wid</a><span style="font-style: italic;"><a style="font-style: italic;" href="chapter_4.1.html#canyon_width_y">th_y</a> ) / 2</span>
    2950 centers the canyon in y-direction.</td></tr><tr>
    2951 
    2952 
    2953 
    2954 
    2955 
    2956 
    2957 
    2958       <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="cloud_droplets"></a>cloud_droplets</span><br>
    2959 
    2960 
    2961 
    2962 
    2963 
    2964 
    2965 
    2966       </td>
    2967 
    2968 
    2969 
    2970 
    2971 
    2972 
    2973  <td style="vertical-align: top;">L<br>
    2974 
    2975 
    2976 
    2977 
    2978 
    2979 
    2980  </td>
    2981 
    2982 
    2983 
    2984 
    2985 
    2986 
    2987 
    2988       <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span><br>
    2989 
    2990 
    2991 
    2992 
    2993 
    2994 
    2995  </td>
    2996 
    2997 
    2998 
    2999 
    3000 
    3001 
    3002 
    3003       <td style="vertical-align: top;">Parameter to switch on
    3004 usage of cloud droplets.<br>
    3005 
    3006 
    3007 
    3008 
    3009 
    3010 
    3011  <br>
    3012 
    3013 
    3014 
    3015 
    3016 
    3017 
    3018 
    3019       <span style="font-weight: bold;"></span><span style="font-family: monospace;"></span>
    3020 
    3021 
    3022 
    3023 
    3024 Cloud droplets require to use&nbsp;particles (i.e. the NAMELIST group <span style="font-family: Courier New,Courier,monospace;">particles_par</span> has to be included in the parameter file<span style="font-family: monospace;"></span>). Then each particle is a representative for a certain number of droplets. The droplet
    3025 features (number of droplets, initial radius, etc.) can be steered with
    3026 the&nbsp; respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
    3027 The real number of initial droplets in a grid cell is equal to the
    3028 initial number of droplets (defined by the particle source parameters <span lang="en-GB"><font face="Thorndale, serif"> </font></span><a href="chapter_4.2.html#pst"><span lang="en-GB"><font face="Thorndale, serif">pst</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psl"><span lang="en-GB"><font face="Thorndale, serif">psl</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psr"><span lang="en-GB"><font face="Thorndale, serif">psr</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pss"><span lang="en-GB"><font face="Thorndale, serif">pss</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psn"><span lang="en-GB"><font face="Thorndale, serif">psn</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psb"><span lang="en-GB"><font face="Thorndale, serif">psb</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pdx"><span lang="en-GB"><font face="Thorndale, serif">pdx</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pdy"><span lang="en-GB"><font face="Thorndale, serif">pdy</font></span></a>
    3029       <span lang="en-GB"><font face="Thorndale, serif">and
    3030       </font></span><a href="chapter_4.2.html#pdz"><span lang="en-GB"><font face="Thorndale, serif">pdz</font></span></a><span lang="en-GB"></span><span lang="en-GB"></span>)
    3031 times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
    3032 
    3033 
    3034 
    3035 
    3036 
    3037 
    3038 
    3039       <br>
    3040 
    3041 
    3042 
    3043 
    3044 
    3045 
    3046 
    3047 In case of using cloud droplets, the default condensation scheme in
    3048 PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
    3049 must be set <span style="font-style: italic;">.F.</span>.<br>
    3050 
    3051 
    3052 
    3053 
    3054 
    3055 
    3056 
    3057       </td>
    3058 
    3059 
    3060 
    3061 
    3062 
    3063 
    3064  </tr>
    3065 
    3066 
    3067 
    3068 
    3069 
    3070 
    3071  <tr>
    3072 
    3073 
    3074 
    3075 
    3076 
    3077 
    3078  <td style="vertical-align: top;">
    3079      
    3080      
    3081      
    3082      
    3083      
    3084      
    3085       <p><a name="cloud_physics"></a><b>cloud_physics</b></p>
    3086 
    3087 
    3088 
    3089 
    3090 
    3091 
    3092 
    3093       </td>
    3094 
    3095 
    3096 
    3097 
    3098 
    3099 
    3100  <td style="vertical-align: top;">L<br>
    3101 
    3102 
    3103 
    3104 
    3105 
    3106 
    3107  </td>
    3108 
    3109 
    3110 
    3111 
    3112 
    3113 
    3114 
    3115       <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
    3116 
    3117 
    3118 
    3119 
    3120 
    3121 
    3122  <td style="vertical-align: top;">
    3123      
    3124      
    3125      
    3126      
    3127      
    3128      
    3129       <p>Parameter to switch
    3130 on the condensation scheme.&nbsp; </p>
    3131 
    3132 
    3133 
    3134 
    3135 
    3136 
    3137 
    3138 For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
    3139 for the
    3140 liquid water&nbsp;
    3141 content and the liquid water potential temperature are solved instead
    3142 of those for specific humidity and potential temperature. Note
    3143 that a grid volume is assumed to be either completely saturated or
    3144 completely
    3145 unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
    3146 additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
    3147 Also cloud-top cooling by longwave radiation can be utilized (see <a href="#radiation">radiation</a>)<br>
    3148 
    3149 
    3150 
    3151 
    3152 
    3153 
    3154  <b><br>
    3155 
    3156 
    3157 
    3158 
    3159 
    3160 
    3161 
    3162 cloud_physics =</b> <span style="font-style: italic;">.TRUE.
    3163       </span>requires&nbsp;<a href="#humidity">humidity</a>
    3164 =<span style="font-style: italic;"> .TRUE.</span> .<br>
    3165 
    3166 
    3167 
    3168 
    3169 
    3170 
    3171 
    3172 Detailed information about the condensation scheme is given in the
    3173 description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
    3174 physics module</a> (pdf-file, only in German).<br>
    3175 
    3176 
    3177 
    3178 
    3179 
    3180 
    3181  <br>
    3182 
    3183 
    3184 
    3185 
    3186 
    3187 
    3188 
    3189 This condensation scheme is not allowed if cloud droplets are simulated
    3190 explicitly (see <a href="#cloud_droplets">cloud_droplets</a>).<br>
    3191 
    3192 
    3193 
    3194 
    3195 
    3196 
    3197 
    3198       </td>
    3199 
    3200 
    3201 
    3202 
    3203 
    3204 
    3205  </tr>
    3206 
    3207 
    3208 
    3209 
    3210 
    3211 
    3212  <tr>
    3213 
    3214 
    3215 
    3216 
    3217 
    3218 
    3219  <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow"></a>conserve_volume_flow</span></td>
    3220 
    3221 
    3222 
    3223 
    3224 
    3225 
    3226 
    3227       <td style="vertical-align: top;">L</td>
    3228 
    3229 
    3230 
    3231 
    3232 
    3233 
    3234  <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
    3235 
    3236 
    3237 
    3238 
    3239 
    3240 
    3241  <td>Conservation
    3242 of volume flow in x- and y-direction.<br>
    3243 
    3244 
    3245 
    3246 
    3247 
    3248 
    3249  <br>
    3250 
    3251 
    3252 
    3253 
    3254 
    3255 
    3256  <span style="font-weight: bold;">conserve_volume_flow</span>
    3257 = <span style="font-style: italic;">.T.</span>
    3258 guarantees that the volume flow through the xz- and yz-cross-sections of
    3259 the total model domain remains constant throughout the run depending on the chosen <a href="#conserve_volume_flow_mode">conserve_volume_flow_mode</a>.<br><br>Note that&nbsp;<span style="font-weight: bold;">conserve_volume_flow</span>
    3260 = <span style="font-style: italic;">.T.</span> requires <a href="#dp_external">dp_external</a> = <span style="font-style: italic;">.F.</span> .<br>
    3261 
    3262 
    3263 
    3264 
    3265 
    3266 
    3267 
    3268       </td>
    3269 
    3270 
    3271 
    3272 
    3273 
    3274 
    3275  </tr>
    3276 
    3277 
    3278 
    3279 
    3280 
    3281 
    3282  <tr><td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow_mode"></a>conserve_volume_flow_mode</span></td><td style="vertical-align: top;">C * 16</td><td style="vertical-align: top;"><span style="font-style: italic;">'default'</span></td><td>Modus of volume flow conservation.<br><br>The following values are allowed:<br><p style="font-style: normal;"><span style="font-style: italic;">'default'</span>
    3283       </p>
    3284 
    3285 
    3286 
    3287 
    3288 
    3289 
    3290  
    3291      
    3292      
    3293      
    3294      
    3295      
    3296      
    3297       <ul><p>Per default, PALM uses&nbsp;<span style="font-style: italic;">'initial_profiles'</span> for cyclic lateral boundary conditions (<a href="#bc_lr">bc_lr</a> = <span style="font-style: italic;">'cyclic'</span> and <a href="#bc_ns">bc_ns</a> = <span style="font-style: italic;">'cyclic'</span>) and&nbsp;<span style="font-style: italic;">'inflow_profile'</span> for non-cyclic lateral boundary conditions (<a href="chapter_4.1.html#bc_lr">bc_lr</a> /= <span style="font-style: italic;">'cyclic'</span> or <a href="chapter_4.1.html#bc_ns">bc_ns</a> /= <span style="font-style: italic;">'cyclic'</span>).</p></ul>
    3298 
    3299 
    3300 
    3301 
    3302 
    3303 
    3304  
    3305      
    3306      
    3307      
    3308      
    3309      
    3310      
    3311       <p style="font-style: italic;">'initial_profiles' </p>
    3312 
    3313 
    3314 
    3315 
    3316 
    3317 
    3318 
    3319      
    3320      
    3321      
    3322      
    3323      
    3324      
    3325       <ul><p>The
    3326 target volume flow&nbsp;is calculated at t=0 from the initial profiles
    3327 of u and v.&nbsp;This setting is only allowed for&nbsp;cyclic lateral
    3328 boundary conditions (<a href="chapter_4.1.html#bc_lr">bc_lr</a> = <span style="font-style: italic;">'cyclic'</span> and <a href="chapter_4.1.html#bc_ns">bc_ns</a> = <span style="font-style: italic;">'cyclic'</span>).</p></ul>
    3329 
    3330 
    3331 
    3332 
    3333 
    3334 
    3335  
    3336      
    3337      
    3338      
    3339      
    3340      
    3341      
    3342       <p style="font-style: normal;"><span style="font-style: italic;">'inflow_profile'</span>
    3343       </p>
    3344 
    3345 
    3346 
    3347 
    3348 
    3349 
    3350  
    3351      
    3352      
    3353      
    3354      
    3355      
    3356      
    3357       <ul><p>The
    3358 target volume flow&nbsp;is&nbsp;calculated at every timestep from the
    3359 inflow profile of&nbsp;u or v, respectively. This setting&nbsp;is only
    3360 allowed for&nbsp;non-cyclic lateral boundary conditions (<a href="chapter_4.1.html#bc_lr">bc_lr</a> /= <span style="font-style: italic;">'cyclic'</span> or <a href="chapter_4.1.html#bc_ns">bc_ns</a> /= <span style="font-style: italic;">'cyclic'</span>).</p></ul>
    3361 
    3362 
    3363 
    3364 
    3365 
    3366 
    3367  
    3368      
    3369      
    3370      
    3371      
    3372      
    3373      
    3374       <p style="font-style: italic;">'bulk_velocity' </p>
    3375 
    3376 
    3377 
    3378 
    3379 
    3380 
    3381 
    3382      
    3383      
    3384      
    3385      
    3386      
    3387      
    3388       <ul><p>The target volume flow is calculated from a predefined bulk velocity (see <a href="#u_bulk">u_bulk</a> and <a href="#v_bulk">v_bulk</a>). This setting is only allowed for&nbsp;cyclic lateral boundary conditions (<a href="chapter_4.1.html#bc_lr">bc_lr</a> = <span style="font-style: italic;">'cyclic'</span> and <a href="chapter_4.1.html#bc_ns">bc_ns</a> = <span style="font-style: italic;">'cyclic'</span>).</p></ul>
    3389 
    3390 
    3391 
    3392 
    3393 
    3394 
    3395  
    3396      
    3397      
    3398      
    3399      
    3400      
    3401      
    3402       <span style="font-style: italic;"></span>Note that&nbsp;<span style="font-weight: bold;">conserve_volume_flow_mode</span>
    3403 only comes into effect if <a href="#conserve_volume_flow">conserve_volume_flow</a> = <span style="font-style: italic;">.T. .</span> </td></tr><tr>
    3404 
    3405       <td style="vertical-align: top;"><a name="cthf"></a><span style="font-weight: bold;">cthf</span></td>
    3406 
    3407       <td style="vertical-align: top;">R</td>
    3408 
    3409       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    3410 
    3411       <td style="vertical-align: top;">Average heat flux that is prescribed at the top of the plant canopy.<br>
    3412 
    3413 
    3414       <br>
    3415 
    3416 
    3417 If <a href="#plant_canopy">plant_canopy</a> is set <span style="font-style: italic;">.T.</span>, the user can prescribe a heat flux at the top of the plant canopy.<br>
    3418 
    3419 
    3420 It is assumed that solar radiation penetrates the canopy and warms the
    3421 foliage which, in turn, warms the air in contact with it. <br>
    3422 
    3423 
    3424 Note: Instead of using the value prescribed by <a href="#surface_heatflux">surface_heatflux</a>,
    3425 the near surface heat flux is determined from an exponential function
    3426 that is dependent on the cumulative leaf_area_index (Shaw and Schumann
    3427 (1992, Boundary Layer Meteorol., 61, 47-64)).</td>
    3428 
    3429     </tr>
    3430 
    3431     <tr>
    3432 
    3433 
    3434 
    3435 
    3436 
    3437 
    3438  <td style="vertical-align: top;">
    3439      
    3440      
    3441      
    3442      
    3443      
    3444      
    3445       <p><a name="cut_spline_overshoot"></a><b>cut_spline_overshoot</b></p>
    3446 
    3447 
    3448 
    3449 
    3450 
    3451 
    3452 
    3453       </td>
    3454 
    3455 
    3456 
    3457 
    3458 
    3459 
    3460  <td style="vertical-align: top;">L</td>
    3461 
    3462 
    3463 
    3464 
    3465 
    3466 
    3467 
    3468       <td style="vertical-align: top;"><span style="font-style: italic;">.T.</span></td>
    3469 
    3470 
    3471 
    3472 
    3473 
    3474 
    3475  <td style="vertical-align: top;">
    3476      
    3477      
    3478      
    3479      
    3480      
    3481      
    3482       <p>Cuts off of
    3483 so-called overshoots, which can occur with the
    3484 upstream-spline scheme.&nbsp; </p>
    3485 
    3486 
    3487 
    3488 
    3489 
    3490 
    3491  
    3492      
    3493      
    3494      
    3495      
    3496      
    3497      
    3498       <p><font color="#000000">The cubic splines tend to overshoot in
    3499 case of discontinuous changes of variables between neighbouring grid
    3500 points.</font><font color="#ff0000"> </font><font color="#000000">This
    3501 may lead to errors in calculating the advection tendency.</font>
    3502 Choice
    3503 of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
    3504 (switched on by
    3505 default)
    3506 allows variable values not to exceed an interval defined by the
    3507 respective adjacent grid points. This interval can be adjusted
    3508 seperately for every prognostic variable (see initialization parameters
    3509       <a href="#overshoot_limit_e">overshoot_limit_e</a>, <a href="#overshoot_limit_pt">overshoot_limit_pt</a>, <a href="#overshoot_limit_u">overshoot_limit_u</a>,
    3510 etc.). This might be necessary in case that the
    3511 default interval has a non-tolerable effect on the model
    3512 results.&nbsp; </p>
    3513 
    3514 
    3515 
    3516 
    3517 
    3518 
    3519  
    3520      
    3521      
    3522      
    3523      
    3524      
    3525      
    3526       <p>Overshoots may also be removed
    3527 using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
    3528       <a href="#ups_limit_pt">ups_limit_pt</a>,
    3529 etc. as well as by applying a long-filter (see <a href="#long_filter_factor">long_filter_factor</a>).</p>
    3530 
    3531 
    3532 
    3533 
    3534 
    3535 
    3536 
    3537       </td>
    3538 
    3539 
    3540 
    3541 
    3542 
    3543 
    3544  </tr>
    3545 
    3546 
    3547 
    3548 
    3549 
    3550 
    3551  <tr>
    3552 
    3553 
    3554 
    3555 
    3556 
    3557 
    3558  <td style="vertical-align: top;">
    3559      
    3560      
    3561      
    3562      
    3563      
    3564      
    3565       <p><a name="damp_level_1d"></a><b>damp_level_1d</b></p>
    3566 
    3567 
    3568 
    3569 
    3570 
    3571 
    3572 
    3573       </td>
    3574 
    3575 
    3576 
    3577 
    3578 
    3579 
    3580  <td style="vertical-align: top;">R</td>
    3581 
    3582 
    3583 
    3584 
    3585 
    3586 
    3587 
    3588       <td style="vertical-align: top;"><span style="font-style: italic;">zu(nz+1)</span></td>
    3589 
    3590 
    3591 
    3592 
    3593 
    3594 
    3595 
    3596       <td style="vertical-align: top;">
    3597      
    3598      
    3599      
    3600      
    3601      
    3602      
    3603       <p>Height where
    3604 the damping layer begins in the 1d-model
    3605 (in m).&nbsp; </p>
    3606 
    3607 
    3608 
    3609 
    3610 
    3611 
    3612  
    3613      
    3614      
    3615      
    3616      
    3617      
    3618      
    3619       <p>This parameter is used to
    3620 switch on a damping layer for the
    3621 1d-model, which is generally needed for the damping of inertia
    3622 oscillations. Damping is done by gradually increasing the value
    3623 of the eddy diffusivities about 10% per vertical grid level
    3624 (starting with the value at the height given by <b>damp_level_1d</b>,
    3625 or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
    3626 =
    3627 1.1 * K<sub>m</sub>(k).
    3628 The values of K<sub>m</sub> are limited to 10 m**2/s at
    3629 maximum.&nbsp; <br>
    3630 
    3631 
    3632 
    3633 
    3634 
    3635 
    3636 
    3637 This parameter only comes into effect if the 1d-model is switched on
    3638 for
    3639 the initialization of the 3d-model using <a href="#initializing_actions">initializing_actions</a>
    3640 = <span style="font-style: italic;">'set_1d-model_profiles'</span>.
    3641       <br>
    3642 
    3643 
    3644 
    3645 
    3646 
    3647 
    3648  </p>
    3649 
    3650 
    3651 
    3652 
    3653 
    3654 
    3655  </td>
    3656 
    3657 
    3658 
    3659 
    3660 
    3661 
    3662  </tr>
    3663 
    3664 
    3665 
    3666 
    3667 
    3668 
    3669  <tr>
    3670 
    3671 
    3672 
    3673 
    3674 
    3675 
    3676  <td style="vertical-align: top;"><a name="dissipation_1d"></a><span style="font-weight: bold;">dissipation_1d</span><br>
    3677 
    3678 
    3679 
    3680 
    3681 
    3682 
    3683 
    3684       </td>
    3685 
    3686 
    3687 
    3688 
    3689 
    3690 
    3691  <td style="vertical-align: top;">C*20<br>
    3692 
    3693 
    3694 
    3695 
    3696 
    3697 
    3698 
    3699       </td>
    3700 
    3701 
    3702 
    3703 
    3704 
    3705 
    3706  <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
    3707 
    3708 
    3709 
    3710 
    3711 
    3712 
    3713  <span style="font-style: italic;">model'</span><br>
    3714 
    3715 
    3716 
    3717 
    3718 
    3719 
    3720  </td>
    3721 
    3722 
    3723 
    3724 
    3725 
    3726 
    3727 
    3728       <td style="vertical-align: top;">Calculation method for
    3729 the energy dissipation term in the TKE equation of the 1d-model.<br>
    3730 
    3731 
    3732 
    3733 
    3734 
    3735 
    3736 
    3737       <br>
    3738 
    3739 
    3740 
    3741 
    3742 
    3743 
    3744 
    3745 By default the dissipation is calculated as in the 3d-model using diss
    3746 = (0.19 + 0.74 * l / l_grid) * e**1.5 / l.<br>
    3747 
    3748 
    3749 
    3750 
    3751 
    3752 
    3753  <br>
    3754 
    3755 
    3756 
    3757 
    3758 
    3759 
    3760 
    3761 Setting <span style="font-weight: bold;">dissipation_1d</span>
    3762 = <span style="font-style: italic;">'detering'</span>
    3763 forces the dissipation to be calculated as diss = 0.064 * e**1.5 / l.<br>
    3764 
    3765 
    3766 
    3767 
    3768 
    3769 
    3770 
    3771       </td>
    3772 
    3773 
    3774 
    3775 
    3776 
    3777 
    3778  </tr>
    3779     <tr><td style="vertical-align: top;"><p><a name="dp_external"></a><b>dp_external</b></p></td><td style="vertical-align: top;">L</td><td style="vertical-align: top; font-style: italic;">.F.</td><td>External pressure gradient switch.<br><br>This
    3780 parameter is used to switch on/off an external pressure gradient as
    3781 driving force. The external pressure gradient is controlled by the
    3782 parameters <a href="#dp_smooth">dp_smooth</a>, <a href="#dp_level_b">dp_level_b</a> and <a href="#dpdxy">dpdxy</a>.<br><br>Note that&nbsp;<span style="font-weight: bold;">dp_external</span> = <span style="font-style: italic;">.T.</span> requires <a href="#conserve_volume_flow">conserve_volume_flow</a> =<span style="font-style: italic;"> .F. </span>It is normally recommended to disable the Coriolis force by setting <a href="l#omega">omega</a> = 0.0.</td></tr><tr><td style="vertical-align: top;"><p><a name="dp_smooth"></a><b>dp_smooth</b></p></td><td style="vertical-align: top;">L</td><td style="vertical-align: top; font-style: italic;">.F.</td><td>Vertically smooth the external pressure gradient using a sinusoidal smoothing function.<br><br>This parameter only applies if <a href="#dp_external">dp_external</a> = <span style="font-style: italic;">.T. </span>. It is useful in combination with&nbsp;<a href="#dp_level_b">dp_level_b</a> &gt;&gt; 0 to generate a non-accelerated boundary layer well below&nbsp;<a href="#dp_level_b">dp_level_b</a>.</td></tr><tr><td style="vertical-align: top;"><p><a name="dp_level_b"></a><b>dp_level_b</b></p></td><td style="vertical-align: top;">R</td><td style="vertical-align: top; font-style: italic;">0.0</td><td><font size="3">Lower
    3783 limit of the vertical range for which the external pressure gradient is applied (</font>in <font size="3">m).</font><br><br>This parameter only applies if <a href="#dp_external">dp_external</a> = <span style="font-style: italic;">.T. </span><span lang="en-GB">It
    3784 must hold the condition zu(0) &lt;= <b>dp_level_b</b>
    3785 &lt;= zu(</span><a href="#nz"><span lang="en-GB">nz</span></a><span lang="en-GB">)</span><span lang="en-GB">.&nbsp;</span>It can be used in combination with&nbsp;<a href="#dp_smooth">dp_smooth</a> = <span style="font-style: italic;">.T.</span> to generate a non-accelerated boundary layer well below&nbsp;<span style="font-weight: bold;">dp_level_b</span> if&nbsp;<span style="font-weight: bold;">dp_level_b</span> &gt;&gt; 0.<br><br>Note
    3786 that there is no upper limit of the vertical range because the external
    3787 pressure gradient is always applied up to the top of the model domain.</td></tr><tr><td style="vertical-align: top;"><p><a name="dpdxy"></a><b>dpdxy</b></p></td><td style="vertical-align: top;">R(2)</td><td style="font-style: italic; vertical-align: top;">2 * 0.0</td><td>Values of the external pressure gradient applied in x- and y-direction, respectively (in Pa/m).<br><br>This parameter only applies if <a href="#dp_external">dp_external</a> = <span style="font-style: italic;">.T. </span>It sets the pressure gradient values. Negative values mean an acceleration, positive values mean deceleration. For example, <span style="font-weight: bold;">dpdxy</span> = -0.0002, 0.0, drives the flow in positive x-direction, <span lang="en-GB"></span></td></tr>
    3788 
    3789 
    3790 
    3791 
    3792 
    3793 
    3794     <tr>
    3795 
    3796       <td style="vertical-align: top;"><a name="drag_coefficient"></a><span style="font-weight: bold;">drag_coefficient</span></td>
    3797 
    3798       <td style="vertical-align: top;">R</td>
    3799 
    3800       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    3801 
    3802       <td style="vertical-align: top;">Drag coefficient used in the plant canopy model.<br>
    3803 
    3804       <br>
    3805 
    3806 This parameter has to be non-zero, if the parameter <a href="#plant_canopy">plant_canopy</a> is set <span style="font-style: italic;">.T.</span>.</td>
    3807 
    3808     </tr>
    3809 
    3810     <tr>
    3811 
    3812 
    3813 
    3814 
    3815 
    3816 
    3817  <td style="vertical-align: top;">
    3818      
    3819      
    3820      
    3821      
    3822      
    3823      
    3824       <p><a name="dt"></a><b>dt</b></p>
    3825 
    3826 
    3827 
    3828 
    3829 
    3830 
    3831  </td>
    3832 
    3833 
    3834 
    3835 
    3836 
    3837 
    3838 
    3839       <td style="vertical-align: top;">R</td>
    3840 
    3841 
    3842 
    3843 
    3844 
    3845 
    3846  <td style="vertical-align: top;"><span style="font-style: italic;">variable</span></td>
    3847 
    3848 
    3849 
    3850 
    3851 
    3852 
    3853 
    3854       <td style="vertical-align: top;">
    3855      
    3856      
    3857      
    3858      
    3859      
    3860      
    3861       <p>Time step for
    3862 the 3d-model (in s).&nbsp; </p>
    3863 
    3864 
    3865 
    3866 
    3867 
    3868 
    3869  
    3870      
    3871      
    3872      
    3873      
    3874      
    3875      
    3876       <p>By default, (i.e.
    3877 if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
    3878 the value of the time step is calculating after each time step
    3879 (following the time step criteria) and
    3880 used for the next step.</p>
    3881 
    3882 
    3883 
    3884 
    3885 
    3886 
    3887  
    3888      
    3889      
    3890      
    3891      
    3892      
    3893      
    3894       <p>If the user assigns <b>dt</b>
    3895 a value, then the time step is
    3896 fixed to this value throughout the whole run (whether it fulfills the
    3897 time step
    3898 criteria or not). However, changes are allowed for restart runs,
    3899 because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
    3900 parameter</a>.&nbsp; </p>
    3901 
    3902 
    3903 
    3904 
    3905 
    3906 
    3907  
    3908      
    3909      
    3910      
    3911      
    3912      
    3913      
    3914       <p>In case that the
    3915 calculated time step meets the condition<br>
    3916 
    3917 
    3918 
    3919 
    3920 
    3921 
    3922  </p>
    3923 
    3924 
    3925 
    3926 
    3927 
    3928 
    3929  
    3930      
    3931      
    3932      
    3933      
    3934      
    3935      
    3936       <ul>
    3937 
    3938 
    3939 
    3940 
    3941 
    3942 
    3943 
    3944        
    3945        
    3946        
    3947        
    3948        
    3949        
    3950         <p><b>dt</b> &lt; 0.00001 * <a href="chapter_4.2.html#dt_max">dt_max</a> (with dt_max
    3951 = 20.0)</p>
    3952 
    3953 
    3954 
    3955 
    3956 
    3957 
    3958  
    3959      
    3960      
    3961      
    3962      
    3963      
    3964      
    3965       </ul>
    3966 
    3967 
    3968 
    3969 
    3970 
    3971 
    3972  
    3973      
    3974      
    3975      
    3976      
    3977      
    3978      
    3979       <p>the simulation will be
    3980 aborted. Such situations usually arise
    3981 in case of any numerical problem / instability which causes a
    3982 non-realistic increase of the wind speed.&nbsp; </p>
    3983 
    3984 
    3985 
    3986 
    3987 
    3988 
    3989  
    3990      
    3991      
    3992      
    3993      
    3994      
    3995      
    3996       <p>A
    3997 small time step due to a large mean horizontal windspeed
    3998 speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
    3999 in order to spare CPU time.<br>
    4000 
    4001 
    4002 
    4003 
    4004 
    4005 
    4006  </p>
    4007 
    4008 
    4009 
    4010 
    4011 
    4012 
    4013  
    4014      
    4015      
    4016      
    4017      
    4018      
    4019      
    4020       <p>If the
    4021 leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
    4022 a temporary time step value dt_new is calculated first, with dt_new = <a href="chapter_4.2.html#fcl_factor">cfl_factor</a>
    4023 * dt_crit where dt_crit is the maximum timestep allowed by the CFL and
    4024 diffusion condition. Next it is examined whether dt_new exceeds or
    4025 falls below the
    4026 value of the previous timestep by at
    4027 least +5 % / -2%. If it is smaller, <span style="font-weight: bold;">dt</span>
    4028 = dt_new is immediately used for the next timestep. If it is larger,
    4029 then <span style="font-weight: bold;">dt </span>=
    4030 1.02 * dt_prev
    4031 (previous timestep) is used as the new timestep, however the time
    4032 step is only increased if the last change of the time step is dated
    4033 back at
    4034 least 30 iterations. If dt_new is located in the interval mentioned
    4035 above, then dt
    4036 does not change at all. By doing so, permanent time step changes as
    4037 well as large
    4038 sudden changes (increases) in the time step are avoided.</p>
    4039 
    4040 
    4041 
    4042 
    4043 
    4044 
    4045  </td>
    4046 
    4047 
    4048 
    4049 
    4050 
    4051 
    4052 
    4053     </tr>
    4054 
    4055 
    4056 
    4057 
    4058 
    4059 
    4060  <tr>
    4061 
    4062 
    4063 
    4064 
    4065 
    4066 
    4067  <td style="vertical-align: top;">
    4068      
    4069      
    4070      
    4071      
    4072      
    4073      
    4074       <p><a name="dt_pr_1d"></a><b>dt_pr_1d</b></p>
    4075 
    4076 
    4077 
    4078 
    4079 
    4080 
    4081 
    4082       </td>
    4083 
    4084 
    4085 
    4086 
    4087 
    4088 
    4089  <td style="vertical-align: top;">R</td>
    4090 
    4091 
    4092 
    4093 
    4094 
    4095 
    4096 
    4097       <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
    4098 
    4099 
    4100 
    4101 
    4102 
    4103 
    4104 
    4105       <td style="vertical-align: top;">
    4106      
    4107      
    4108      
    4109      
    4110      
    4111      
    4112       <p>Temporal
    4113 interval of vertical profile output of the 1D-model
    4114 (in s).&nbsp; </p>
    4115 
    4116 
    4117 
    4118 
    4119 
    4120 
    4121  
    4122      
    4123      
    4124      
    4125      
    4126      
    4127      
    4128       <p>Data are written in ASCII
    4129 format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
    4130 This parameter is only in effect if the 1d-model has been switched on
    4131 for the
    4132 initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
    4133 = <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
    4134 
    4135 
    4136 
    4137 
    4138 
    4139 
    4140 
    4141       </td>
    4142 
    4143 
    4144 
    4145 
    4146 
    4147 
    4148  </tr>
    4149 
    4150 
    4151 
    4152 
    4153 
    4154 
    4155  <tr>
    4156 
    4157 
    4158 
    4159 
    4160 
    4161 
    4162  <td style="vertical-align: top;">
    4163      
    4164      
    4165      
    4166      
    4167      
    4168      
    4169       <p><a name="dt_run_control_1d"></a><b>dt_run_control_1d</b></p>
    4170 
    4171 
    4172 
    4173 
    4174 
    4175 
    4176 
    4177       </td>
    4178 
    4179 
    4180 
    4181 
    4182 
    4183 
    4184  <td style="vertical-align: top;">R</td>
    4185 
    4186 
    4187 
    4188 
    4189 
    4190 
    4191 
    4192       <td style="vertical-align: top;"><span style="font-style: italic;">60.0</span></td>
    4193 
    4194 
    4195 
    4196 
    4197 
    4198 
    4199  <td style="vertical-align: top;">
    4200      
    4201      
    4202      
    4203      
    4204      
    4205      
    4206       <p>Temporal interval of
    4207 runtime control output of the 1d-model
    4208 (in s).&nbsp; </p>
    4209 
    4210 
    4211 
    4212 
    4213 
    4214 
    4215  
    4216      
    4217      
    4218      
    4219      
    4220      
    4221      
    4222       <p>Data are written in ASCII
    4223 format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
    4224 This parameter is only in effect if the 1d-model is switched on for the
    4225 initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
    4226 = <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
    4227 
    4228 
    4229 
    4230 
    4231 
    4232 
    4233 
    4234       </td>
    4235 
    4236 
    4237 
    4238 
    4239 
    4240 
    4241  </tr>
    4242 
    4243 
    4244 
    4245 
    4246 
    4247 
    4248  <tr>
    4249 
    4250 
    4251 
    4252 
    4253 
    4254 
    4255  <td style="vertical-align: top;">
    4256      
    4257      
    4258      
    4259      
    4260      
    4261      
    4262       <p><a name="dx"></a><b>dx</b></p>
    4263 
    4264 
    4265 
    4266 
    4267 
    4268 
    4269 
    4270       </td>
    4271 
    4272 
    4273 
    4274 
    4275 
    4276 
    4277  <td style="vertical-align: top;">R</td>
    4278 
    4279 
    4280 
    4281 
    4282 
    4283 
    4284 
    4285       <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
    4286 
    4287 
    4288 
    4289 
    4290 
    4291 
    4292  <td style="vertical-align: top;">
    4293      
    4294      
    4295      
    4296      
    4297      
    4298      
    4299       <p>Horizontal grid
    4300 spacing along the x-direction (in m).&nbsp; </p>
    4301 
    4302 
    4303 
    4304 
    4305 
    4306 
    4307  
    4308      
    4309      
    4310      
    4311      
    4312      
    4313      
    4314       <p>Along
    4315 x-direction only a constant grid spacing is allowed.</p>
    4316 
    4317 
    4318 
    4319 
    4320 
    4321 
    4322      
    4323      
    4324      
    4325      
    4326      
    4327      
    4328       <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
    4329 and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
    4330 
    4331 
    4332 
    4333 
    4334 
    4335 
    4336  </td>
    4337 
    4338 
    4339 
    4340 
    4341 
    4342 
    4343 
    4344     </tr>
    4345 
    4346 
    4347 
    4348 
    4349 
    4350 
    4351  <tr>
    4352 
    4353 
    4354 
    4355 
    4356 
    4357 
    4358  <td style="vertical-align: top;">
    4359      
    4360      
    4361      
    4362      
    4363      
    4364      
    4365       <p><a name="dy"></a><b>dy</b></p>
    4366 
    4367 
    4368 
    4369 
    4370 
    4371 
    4372 
    4373       </td>
    4374 
    4375 
    4376 
    4377 
    4378 
    4379 
    4380  <td style="vertical-align: top;">R</td>
    4381 
    4382 
    4383 
    4384 
    4385 
    4386 
    4387 
    4388       <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
    4389 
    4390 
    4391 
    4392 
    4393 
    4394 
    4395  <td style="vertical-align: top;">
    4396      
    4397      
    4398      
    4399      
    4400      
    4401      
    4402       <p>Horizontal grid
    4403 spacing along the y-direction (in m).&nbsp; </p>
    4404 
    4405 
    4406 
    4407 
    4408 
    4409 
    4410  
    4411      
    4412      
    4413      
    4414      
    4415      
    4416      
    4417       <p>Along y-direction only a constant grid spacing is allowed.</p>
    4418 
    4419 
    4420 
    4421 
    4422 
    4423 
    4424      
    4425      
    4426      
    4427      
    4428      
    4429      
    4430       <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
    4431 and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
    4432 
    4433 
    4434 
    4435 
    4436 
    4437 
    4438  </td>
    4439 
    4440 
    4441 
    4442 
    4443 
    4444 
    4445 
    4446     </tr>
    4447 
    4448 
    4449 
    4450 
    4451 
    4452 
    4453  <tr>
    4454 
    4455 
    4456 
    4457 
    4458 
    4459 
    4460  <td style="vertical-align: top;">
    4461      
    4462      
    4463      
    4464      
    4465      
    4466      
    4467       <p><a name="dz"></a><b>dz</b></p>
    4468 
    4469 
    4470 
    4471 
    4472 
    4473 
    4474 
    4475       </td>
    4476 
    4477 
    4478 
    4479 
    4480 
    4481 
    4482  <td style="vertical-align: top;">R</td>
    4483 
    4484 
    4485 
    4486 
    4487 
    4488 
    4489 
    4490       <td style="vertical-align: top;"><br>
    4491 
    4492 
    4493 
    4494 
    4495 
    4496 
    4497  </td>
    4498 
    4499 
    4500 
    4501 
    4502 
    4503 
    4504  <td style="vertical-align: top;">
    4505      
    4506      
    4507      
    4508      
    4509      
    4510      
    4511       <p>Vertical grid
    4512 spacing (in m).&nbsp; </p>
    4513 
    4514 
    4515 
    4516 
    4517 
    4518 
    4519  
    4520      
    4521      
    4522      
    4523      
    4524      
    4525      
    4526       <p>This parameter must be
    4527 assigned by the user, because no
    4528 default value is given.<br>
    4529 
    4530 
    4531 
    4532 
    4533 
    4534 
    4535  </p>
    4536 
    4537 
    4538 
    4539 
    4540 
    4541 
    4542  
    4543      
    4544      
    4545      
    4546      
    4547      
    4548      
    4549       <p>By default, the
    4550 model uses constant grid spacing along z-direction, but it can be
    4551 stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
    4552 and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
    4553 In case of stretching, a maximum allowed grid spacing can be given by <a href="#dz_max">dz_max</a>.<br>
    4554 
    4555 
    4556 
    4557 
    4558 
    4559 
    4560  </p>
    4561 
    4562 
    4563 
    4564 
    4565 
    4566 
    4567  
    4568      
    4569      
    4570      
    4571      
    4572      
    4573      
    4574       <p>Assuming
    4575 a constant <span style="font-weight: bold;">dz</span>,
    4576 the scalar levels (zu) are calculated directly by:&nbsp; </p>
    4577 
    4578 
    4579 
    4580 
    4581 
    4582 
    4583 
    4584      
    4585      
    4586      
    4587      
    4588      
    4589      
    4590       <ul>
    4591 
    4592 
    4593 
    4594 
    4595 
    4596 
    4597  
    4598        
    4599        
    4600        
    4601        
    4602        
    4603        
    4604         <p>zu(0) = - dz * 0.5&nbsp; <br>
    4605 
    4606 
    4607 
    4608 
    4609 
    4610 
    4611 
    4612 zu(1) = dz * 0.5</p>
    4613 
    4614 
    4615 
    4616 
    4617 
    4618 
    4619  
    4620      
    4621      
    4622      
    4623      
    4624      
    4625      
    4626       </ul>
    4627 
    4628 
    4629 
    4630 
    4631 
    4632 
    4633  
    4634      
    4635      
    4636      
    4637      
    4638      
    4639      
    4640       <p>The w-levels lie
    4641 half between them:&nbsp; </p>
    4642 
    4643 
    4644 
    4645 
    4646 
    4647 
    4648  
    4649      
    4650      
    4651      
    4652      
    4653      
    4654      
    4655       <ul>
    4656 
    4657 
    4658 
    4659 
    4660 
    4661 
    4662  
    4663        
    4664        
    4665        
    4666        
    4667        
    4668        
    4669         <p>zw(k) =
    4670 ( zu(k) + zu(k+1) ) * 0.5</p>
    4671 
    4672 
    4673 
    4674 
    4675 
    4676 
    4677  
    4678      
    4679      
    4680      
    4681      
    4682      
    4683      
    4684       </ul>
    4685 
    4686 
    4687 
    4688 
    4689 
    4690 
    4691  </td>
    4692 
    4693 
    4694 
    4695 
    4696 
    4697 
    4698  </tr>
    4699 
    4700 
    4701 
    4702 
    4703 
    4704 
    4705 
    4706     <tr>
    4707 
    4708 
    4709 
    4710 
    4711 
    4712 
    4713       <td style="vertical-align: top;"><a name="dz_max"></a><span style="font-weight: bold;">dz_max</span></td>
    4714 
    4715 
    4716 
    4717 
    4718 
    4719 
    4720       <td style="vertical-align: top;">R</td>
    4721 
    4722 
    4723 
    4724 
    4725 
    4726 
    4727       <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
    4728 
    4729 
    4730 
    4731 
    4732 
    4733 
    4734       <td style="vertical-align: top;">Allowed maximum vertical grid
    4735 spacing (in m).<br>
    4736 
    4737 
    4738 
    4739 
    4740 
    4741 
    4742       <br>
    4743 
    4744 
    4745 
    4746 
    4747 
    4748 
    4749 If the vertical grid is stretched
    4750 (see <a href="#dz_stretch_factor">dz_stretch_factor</a>
    4751 and <a href="#dz_stretch_level">dz_stretch_level</a>),
    4752       <span style="font-weight: bold;">dz_max</span> can
    4753 be used to limit the vertical grid spacing.</td>
    4754 
    4755 
    4756 
    4757 
    4758 
    4759 
    4760     </tr>
    4761 
    4762 
    4763 
    4764 
    4765 
    4766 
    4767     <tr>
    4768 
    4769 
    4770 
    4771 
    4772 
    4773 
    4774 
    4775       <td style="vertical-align: top;">
    4776      
    4777      
    4778      
    4779      
    4780      
    4781      
    4782       <p><a name="dz_stretch_factor"></a><b>dz_stretch_factor</b></p>
    4783 
    4784 
    4785 
    4786 
    4787 
    4788 
    4789 
    4790       </td>
    4791 
    4792 
    4793 
    4794 
    4795 
    4796 
    4797  <td style="vertical-align: top;">R</td>
    4798 
    4799 
    4800 
    4801 
    4802 
    4803 
    4804 
    4805       <td style="vertical-align: top;"><span style="font-style: italic;">1.08</span></td>
    4806 
    4807 
    4808 
    4809 
    4810 
    4811 
    4812  <td style="vertical-align: top;">
    4813      
    4814      
    4815      
    4816      
    4817      
    4818      
    4819       <p>Stretch factor for a
    4820 vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).&nbsp;
    4821       </p>
    4822 
    4823 
    4824 
    4825 
    4826 
    4827 
    4828  
    4829      
    4830      
    4831      
    4832      
    4833      
    4834      
    4835       <p>The stretch factor should not exceed a value of
    4836 approx. 1.10 -
    4837 1.12, otherwise the discretization errors due to the stretched grid not
    4838 negligible any more. (refer Kalnay de Rivas)</p>
    4839 
    4840 
    4841 
    4842 
    4843 
    4844 
    4845  </td>
    4846 
    4847 
    4848 
    4849 
    4850 
    4851 
    4852  </tr>
    4853 
    4854 
    4855 
    4856 
    4857 
    4858 
    4859 
    4860     <tr>
    4861 
    4862 
    4863 
    4864 
    4865 
    4866 
    4867  <td style="vertical-align: top;">
    4868      
    4869      
    4870      
    4871      
    4872      
    4873      
    4874       <p><a name="dz_stretch_level"></a><b>dz_stretch_level</b></p>
    4875 
    4876 
    4877 
    4878 
    4879 
    4880 
    4881 
    4882       </td>
    4883 
    4884 
    4885 
    4886 
    4887 
    4888 
    4889  <td style="vertical-align: top;">R</td>
    4890 
    4891 
    4892 
    4893 
    4894 
    4895 
    4896 
    4897       <td style="vertical-align: top;"><span style="font-style: italic;">100000.0</span><br>
    4898 
    4899 
    4900 
    4901 
    4902 
    4903 
    4904  </td>
    4905 
    4906 
    4907 
    4908 
    4909 
    4910 
    4911 
    4912       <td style="vertical-align: top;">
    4913      
    4914      
    4915      
    4916      
    4917      
    4918      
    4919       <p>Height level
    4920 above/below which the grid is to be stretched
    4921 vertically (in m).&nbsp; </p>
    4922 
    4923 
    4924 
    4925 
    4926 
    4927 
    4928  
    4929      
    4930      
    4931      
    4932      
    4933      
    4934      
    4935       <p>For <a href="chapter_4.1.html#ocean">ocean</a> = .F., <b>dz_stretch_level </b>is the height level (in m)&nbsp;<span style="font-weight: bold;">above </span>which the grid is to be stretched
    4936 vertically. The vertical grid
    4937 spacings <a href="#dz">dz</a>
    4938 above this level are calculated as&nbsp; </p>
    4939 
    4940 
    4941 
    4942 
    4943 
    4944 
    4945  
    4946      
    4947      
    4948      
    4949      
    4950      
    4951      
    4952       <ul>
    4953 
    4954 
    4955 
    4956 
    4957 
    4958 
    4959  
    4960        
    4961        
    4962        
    4963        
    4964        
    4965        
    4966         <p><b>dz</b>(k+1)
    4967 = <b>dz</b>(k) * <a href="#dz_stretch_factor">dz_stretch_factor</a></p>
    4968 
    4969 
    4970 
    4971 
    4972 
    4973 
    4974 
    4975      
    4976      
    4977      
    4978      
    4979      
    4980      
    4981       </ul>
    4982 
    4983 
    4984 
    4985 
    4986 
    4987 
    4988  
    4989      
    4990      
    4991      
    4992      
    4993      
    4994      
    4995       <p>and used as spacings for the scalar levels (zu).
    4996 The
    4997 w-levels are then defined as:&nbsp; </p>
    4998 
    4999 
    5000 
    5001 
    5002 
    5003 
    5004  
    5005      
    5006      
    5007      
    5008      
    5009      
    5010      
    5011       <ul>
    5012 
    5013 
    5014 
    5015 
    5016 
    5017 
    5018  
    5019        
    5020        
    5021        
    5022        
    5023        
    5024        
    5025         <p>zw(k)
    5026 = ( zu(k) + zu(k+1) ) * 0.5.
    5027 
    5028  
    5029      
    5030       </p>
    5031 
    5032 
    5033 
    5034 
    5035      
    5036      
    5037      
    5038      
    5039       </ul>
    5040 
    5041 
    5042 
    5043 
    5044      
    5045      
    5046      
    5047      
    5048       <p>For <a href="#ocean">ocean</a> = .T., <b>dz_stretch_level </b>is the height level (in m, negative) <span style="font-weight: bold;">below</span> which the grid is to be stretched
    5049 vertically. The vertical grid
    5050 spacings <a href="chapter_4.1.html#dz">dz</a> below this level are calculated correspondingly as
    5051 
    5052  
    5053      
    5054       </p>
    5055 
    5056 
    5057 
    5058 
    5059      
    5060      
    5061      
    5062      
    5063       <ul>
    5064 
    5065 
    5066 
    5067 
    5068        
    5069        
    5070        
    5071        
    5072         <p><b>dz</b>(k-1)
    5073 = <b>dz</b>(k) * <a href="chapter_4.1.html#dz_stretch_factor">dz_stretch_factor</a>.</p>
    5074 
    5075 
    5076 
    5077 
    5078      
    5079      
    5080      
    5081      
    5082       </ul>
    5083 
    5084 
    5085 
    5086 
    5087 
    5088 
    5089  </td>
    5090 
    5091 
    5092 
    5093 
    5094 
    5095 
    5096  </tr>
    5097 
    5098 
    5099 
    5100 
    5101 
    5102 
    5103 
    5104     <tr>
    5105 
    5106 
    5107 
    5108 
    5109 
    5110       <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_init"></a>e_init</span></td>
    5111 
    5112 
    5113 
    5114 
    5115 
    5116       <td style="vertical-align: top;">R</td>
    5117 
    5118 
    5119 
    5120 
    5121 
    5122       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    5123 
    5124 
    5125 
    5126 
    5127 
    5128       <td>Initial subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
    5129 
    5130 
    5131 
    5132 
    5133 
    5134 
    5135 
    5136       <br>
    5137 
    5138 
    5139 
    5140 
    5141 
    5142 
    5143 This
    5144 option prescribes an initial&nbsp;subgrid-scale TKE from which the initial diffusion coefficients K<sub>m</sub> and K<sub>h</sub> will be calculated if <span style="font-weight: bold;">e_init</span> is positive. This option only has an effect if&nbsp;<a href="#km_constant">km_constant</a> is not set.</td>
    5145 
    5146 
    5147 
    5148 
    5149 
    5150     </tr>
    5151 
    5152 
    5153 
    5154 
    5155 
    5156     <tr>
    5157 
    5158 
    5159 
    5160 
    5161 
    5162 
    5163  <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_min"></a>e_min</span></td>
    5164 
    5165 
    5166 
    5167 
    5168 
    5169 
    5170 
    5171       <td style="vertical-align: top;">R</td>
    5172 
    5173 
    5174 
    5175 
    5176 
    5177 
    5178  <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    5179 
    5180 
    5181 
    5182 
    5183 
    5184 
    5185  <td>Minimum
    5186 subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
    5187 
    5188 
    5189 
    5190 
    5191 
    5192 
    5193 
    5194       <br>
    5195 
    5196 
    5197 
    5198 
    5199 
    5200 
    5201 This
    5202 option&nbsp;adds artificial viscosity to the flow by ensuring that
    5203 the
    5204 subgrid-scale TKE does not fall below the minimum threshold <span style="font-weight: bold;">e_min</span>.</td>
    5205 
    5206 
    5207 
    5208 
    5209 
    5210 
    5211  </tr>
    5212 
    5213 
    5214 
    5215 
    5216 
    5217 
    5218 
    5219     <tr>
    5220 
    5221 
    5222 
    5223 
    5224 
    5225 
    5226  <td style="vertical-align: top;">
    5227      
    5228      
    5229      
    5230      
    5231      
    5232      
    5233       <p><a name="end_time_1d"></a><b>end_time_1d</b></p>
    5234 
    5235 
    5236 
    5237 
    5238 
    5239 
    5240 
    5241       </td>
    5242 
    5243 
    5244 
    5245 
    5246 
    5247 
    5248  <td style="vertical-align: top;">R</td>
    5249 
    5250 
    5251 
    5252 
    5253 
    5254 
    5255 
    5256       <td style="vertical-align: top;"><span style="font-style: italic;">864000.0</span><br>
    5257 
    5258 
    5259 
    5260 
    5261 
    5262 
    5263  </td>
    5264 
    5265 
    5266 
    5267 
    5268 
    5269 
    5270 
    5271       <td style="vertical-align: top;">
    5272      
    5273      
    5274      
    5275      
    5276      
    5277      
    5278       <p>Time to be
    5279 simulated for the 1d-model (in s).&nbsp; </p>
    5280 
    5281 
    5282 
    5283 
    5284 
    5285 
    5286  
    5287      
    5288      
    5289      
    5290      
    5291      
    5292      
    5293       <p>The
    5294 default value corresponds to a simulated time of 10 days.
    5295 Usually, after such a period the inertia oscillations have completely
    5296 decayed and the solution of the 1d-model can be regarded as stationary
    5297 (see <a href="#damp_level_1d">damp_level_1d</a>).
    5298 This parameter is only in effect if the 1d-model is switched on for the
    5299 initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
    5300 = <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
    5301 
    5302 
    5303 
    5304 
    5305 
    5306 
    5307 
    5308       </td>
    5309 
    5310 
    5311 
    5312 
    5313 
    5314 
    5315  </tr>
    5316 
    5317 
    5318 
    5319 
    5320 
    5321 
    5322  <tr>
    5323 
    5324 
    5325 
    5326 
    5327 
    5328 
    5329  <td style="vertical-align: top;">
    5330      
    5331      
    5332      
    5333      
    5334      
    5335      
    5336       <p><a name="fft_method"></a><b>fft_method</b></p>
    5337 
    5338 
    5339 
    5340 
    5341 
    5342 
    5343 
    5344       </td>
    5345 
    5346 
    5347 
    5348 
    5349 
    5350 
    5351  <td style="vertical-align: top;">C * 20</td>
    5352 
    5353 
    5354 
    5355 
    5356 
    5357 
    5358 
    5359       <td style="vertical-align: top;"><span style="font-style: italic;">'system-</span><br style="font-style: italic;">
    5360 
    5361 
    5362 
    5363 
    5364 
    5365 
    5366  <span style="font-style: italic;">specific'</span></td>
    5367 
    5368 
    5369 
    5370 
    5371 
    5372 
    5373 
    5374       <td style="vertical-align: top;">
    5375      
    5376      
    5377      
    5378      
    5379      
    5380      
    5381       <p>FFT-method to
    5382 be used.<br>
    5383 
    5384 
    5385 
    5386 
    5387 
    5388 
    5389  </p>
    5390 
    5391 
    5392 
    5393 
    5394 
    5395 
    5396  
    5397      
    5398      
    5399      
    5400      
    5401      
    5402      
    5403       <p><br>
    5404 
    5405 
    5406 
    5407 
    5408 
    5409 
    5410 
    5411 The fast fourier transformation (FFT) is used for solving the
    5412 perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
    5413 and for calculating power spectra (see optional software packages,
    5414 section <a href="chapter_4.2.html#spectra_package">4.2</a>).</p>
    5415 
    5416 
    5417 
    5418 
    5419 
    5420 
    5421 
    5422      
    5423      
    5424      
    5425      
    5426      
    5427      
    5428       <p><br>
    5429 
    5430 
    5431 
    5432 
    5433 
    5434 
    5435 
    5436 By default, system-specific, optimized routines from external
    5437 vendor libraries are used. However, these are available only on certain
    5438 computers and there are more or less severe restrictions concerning the
    5439 number of gridpoints to be used with them.<br>
    5440 
    5441 
    5442 
    5443 
    5444 
    5445 
    5446  </p>
    5447 
    5448 
    5449 
    5450 
    5451 
    5452 
    5453  
    5454      
    5455      
    5456      
    5457      
    5458      
    5459      
    5460       <p>There
    5461 are two other PALM internal methods available on every
    5462 machine (their respective source code is part of the PALM source code):</p>
    5463 
    5464 
    5465 
    5466 
    5467 
    5468 
    5469 
    5470      
    5471      
    5472      
    5473      
    5474      
    5475      
    5476       <p>1.: The <span style="font-weight: bold;">Temperton</span>-method
    5477 from Clive Temperton (ECWMF) which is computationally very fast and
    5478 switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
    5479 The number of horizontal gridpoints (nx+1, ny+1) to be used with this
    5480 method must be composed of prime factors 2, 3 and 5.<br>
    5481 
    5482 
    5483 
    5484 
    5485 
    5486 
    5487  </p>
    5488 
    5489 
    5490 
    5491 
    5492 
    5493 
    5494 
    5495 2.: The <span style="font-weight: bold;">Singleton</span>-method
    5496 which is very slow but has no restrictions concerning the number of
    5497 gridpoints to be used with, switched on with <b>fft_method</b>
    5498 = <span style="font-style: italic;">'singleton-algorithm'</span>.
    5499       </td>
    5500 
    5501 
    5502 
    5503 
    5504 
    5505 
    5506  </tr>
    5507 
    5508 
    5509 
    5510 
    5511 
    5512 
    5513  <tr>
    5514 
    5515 
    5516 
    5517 
    5518 
    5519 
    5520  <td style="vertical-align: top;">
    5521      
    5522      
    5523      
    5524      
    5525      
    5526      
    5527       <p><a name="galilei_transformation"></a><b>galilei_transformation</b></p>
    5528 
    5529 
    5530 
    5531 
    5532 
    5533 
    5534 
    5535       </td>
    5536 
    5537 
    5538 
    5539 
    5540 
    5541 
    5542  <td style="vertical-align: top;">L</td>
    5543 
    5544 
    5545 
    5546 
    5547 
    5548 
    5549 
    5550       <td style="vertical-align: top;"><i>.F.</i></td>
    5551 
    5552 
    5553 
    5554 
    5555 
    5556 
    5557 
    5558       <td style="vertical-align: top;">Application of a
    5559 Galilei-transformation to the
    5560 coordinate
    5561 system of the model.<br>
    5562 
    5563 
    5564 
    5565 
    5566 
    5567 
    5568      
    5569      
    5570      
    5571      
    5572      
    5573      
    5574       <p>With <b>galilei_transformation</b>
    5575 = <i>.T.,</i> a so-called
    5576 Galilei-transformation is switched on which ensures that the coordinate
    5577 system of the model is moved along with the geostrophical wind.
    5578 Alternatively, the model domain can be moved along with the averaged
    5579 horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
    5580 this can and will naturally change in time). With this method,
    5581 numerical inaccuracies of the Piascek - Williams - scheme (concerns in
    5582 particular the momentum advection) are minimized. Beyond that, in the
    5583 majority of cases the lower relative velocities in the moved system
    5584 permit a larger time step (<a href="#dt">dt</a>).
    5585 Switching the transformation on is only worthwhile if the geostrophical
    5586 wind (ug, vg)
    5587 and the averaged horizontal wind clearly deviate from the value 0. In
    5588 each case, the distance the coordinate system has been moved is written
    5589 to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.&nbsp;
    5590       </p>
    5591 
    5592 
    5593 
    5594 
    5595 
    5596 
    5597  
    5598      
    5599      
    5600      
    5601      
    5602      
    5603      
    5604       <p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
    5605 and <a href="#bc_ns">bc_ns</a>), the specification
    5606 of a gestrophic
    5607 wind that is not constant with height
    5608 as well as e.g. stationary inhomogeneities at the bottom boundary do
    5609 not allow the use of this transformation.</p>
    5610 
    5611 
    5612 
    5613 
    5614 
    5615 
    5616  </td>
    5617 
    5618 
    5619 
    5620 
    5621 
    5622 
    5623  </tr>
    5624 
    5625 
    5626 
    5627 
    5628 
    5629 
    5630 
    5631     <tr>
    5632 
    5633 
    5634 
    5635 
    5636 
    5637 
    5638  <td style="vertical-align: top;">
    5639      
    5640      
    5641      
    5642      
    5643      
    5644      
    5645       <p><a name="grid_matching"></a><b>grid_matching</b></p>
    5646 
    5647 
    5648 
    5649 
    5650 
    5651 
    5652 
    5653       </td>
    5654 
    5655 
    5656 
    5657 
    5658 
    5659 
    5660  <td style="vertical-align: top;">C * 6</td>
    5661 
    5662 
    5663 
    5664 
    5665 
    5666 
    5667 
    5668       <td style="vertical-align: top;"><span style="font-style: italic;">'strict'</span></td>
    5669 
    5670 
    5671 
    5672 
    5673 
    5674 
    5675  <td style="vertical-align: top;">Variable to adjust the
    5676 subdomain
    5677 sizes in parallel runs.<br>
    5678 
    5679 
    5680 
    5681 
    5682 
    5683 
    5684  <br>
    5685 
    5686 
    5687 
    5688 
    5689 
    5690 
    5691 
    5692 For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
    5693 the subdomains are forced to have an identical
    5694 size on all processors. In this case the processor numbers in the
    5695 respective directions of the virtual processor net must fulfill certain
    5696 divisor conditions concerning the grid point numbers in the three
    5697 directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
    5698 and <a href="#nz">nz</a>).
    5699 Advantage of this method is that all PEs bear the same computational
    5700 load.<br>
    5701 
    5702 
    5703 
    5704 
    5705 
    5706 
    5707  <br>
    5708 
    5709 
    5710 
    5711 
    5712 
    5713 
    5714 
    5715 There is no such restriction by default, because then smaller
    5716 subdomains are allowed on those processors which
    5717 form the right and/or north boundary of the virtual processor grid. On
    5718 all other processors the subdomains are of same size. Whether smaller
    5719 subdomains are actually used, depends on the number of processors and
    5720 the grid point numbers used. Information about the respective settings
    5721 are given in file <a href="file:///home/raasch/public_html/PALM_group/home/raasch/public_html/PALM_group/doc/app/chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.<br>
    5722 
    5723 
    5724 
    5725 
    5726 
    5727 
    5728 
    5729       <br>
    5730 
    5731 
    5732 
    5733 
    5734 
    5735 
    5736 
    5737 When using a multi-grid method for solving the Poisson equation (see <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">psolver</a>)
    5738 only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
    5739 is allowed.<br>
    5740 
    5741 
    5742 
    5743 
    5744 
    5745 
    5746  <br>
    5747 
    5748 
    5749 
    5750 
    5751 
    5752 
    5753  <b>Note:</b><br>
    5754 
    5755 
    5756 
    5757 
    5758 
    5759 
    5760 
    5761 In some cases for small processor numbers there may be a very bad load
    5762 balancing among the
    5763 processors which may reduce the performance of the code.</td>
    5764 
    5765 
    5766 
    5767 
    5768 
    5769 
    5770  </tr>
    5771 
    5772 
    5773 
    5774 
    5775 
    5776 
    5777 
    5778     <tr><td style="vertical-align: top;"><p><a name="humidity"></a><b>humidity</b></p></td><td style="vertical-align: top;">L</td><td style="vertical-align: top;"><i>.F.</i></td><td style="vertical-align: top;"><p>Parameter to
    5779 switch on the prognostic equation for specific
    5780 humidity q.<br>
    5781 
    5782 
    5783 
    5784 
    5785 
    5786 
    5787  </p>
    5788 
    5789 
    5790 
    5791 
    5792 
    5793 
    5794  
    5795      
    5796      
    5797      
    5798      
    5799      
    5800      
    5801       <p>The initial vertical
    5802 profile of q can be set via parameters <a href="chapter_4.1.html#q_surface">q_surface</a>, <a href="chapter_4.1.html#q_vertical_gradient">q_vertical_gradient</a>
    5803 and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.&nbsp;
    5804 Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
    5805 and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
    5806 
    5807 
    5808 
    5809 
    5810 
    5811 
    5812 
    5813       </p>
    5814 
    5815 
    5816 
    5817 
    5818 
    5819 
    5820 
    5821 If the condensation scheme is switched on (<a href="chapter_4.1.html#cloud_physics">cloud_physics</a>
    5822 = .TRUE.), q becomes the total liquid water content (sum of specific
    5823 humidity and liquid water content).</td></tr><tr><td style="vertical-align: top;"><span style="font-weight: bold;"><a name="inflow_damping_height"></a>inflow_damping_height</span></td><td style="vertical-align: top;">R</td><td style="vertical-align: top;"><span style="font-style: italic;">from precursor run</span></td><td style="vertical-align: top;">Height below which the turbulence signal is used for turbulence recycling (in m).<br><br>In case of a turbulent inflow (see <a href="chapter_4.1.html#turbulent_inflow">turbulent_inflow</a>),
    5824 this parameter defines the vertical thickness of the turbulent layer up
    5825 to which the turbulence extracted at the recycling plane (see <a href="chapter_4.1.html#recycling_width">recycling_width</a>)
    5826 shall be imposed to the inflow. Above this level the turbulence signal
    5827 is linearly damped to zero. The transition range within which the
    5828 signal falls to zero is given by the parameter <a href="chapter_4.1.html#inflow_damping_width">inflow_damping_width</a>.<br><br>By default, this height is set as the height of the convective boundary layer as calculated from a precursor run. See <a href="chapter_3.9.html">chapter 3.9</a> about proper settings for getting this CBL height from a precursor run. </td></tr><tr><td style="vertical-align: top;"><span style="font-weight: bold;"><a name="inflow_damping_width"></a>inflow_damping_width</span></td><td style="vertical-align: top;">R</td><td style="vertical-align: top;"><span style="font-style: italic;">0.1 * <a href="chapter_4.1.html#inflow_damping_height">inflow_damping</a></span><a href="chapter_4.1.html#inflow_damping_height"><br style="font-style: italic;"><span style="font-style: italic;">_height</span></a></td><td style="vertical-align: top;">Transition range within which the turbulance signal is damped to zero (in m).<br><br>See <a href="chapter_4.1.html#inflow_damping_height">inflow_damping_height</a> for explanation.</td></tr><tr>
    5829 
    5830 
    5831 
    5832 
    5833 
    5834 
    5835  <td style="vertical-align: top;"><a name="inflow_disturbance_begin"></a><b>inflow_disturbance_<br>
    5836 
    5837 
    5838 
    5839 
    5840 
    5841 
    5842 
    5843 begin</b></td>
    5844 
    5845 
    5846 
    5847 
    5848 
    5849 
    5850  <td style="vertical-align: top;">I</td>
    5851 
    5852 
    5853 
    5854 
    5855 
    5856 
    5857 
    5858       <td style="vertical-align: top;"><span style="font-style: italic;">MIN(10,</span><br style="font-style: italic;">
    5859 
    5860 
    5861 
    5862 
    5863 
    5864 
    5865  <span style="font-style: italic;">nx/2 or ny/2)</span></td>
    5866 
    5867 
    5868 
    5869 
    5870 
    5871 
    5872 
    5873       <td style="vertical-align: top;">Lower
    5874 limit of the horizontal range for which random perturbations are to be
    5875 imposed on the horizontal velocity field (gridpoints).<br>
    5876 
    5877 
    5878 
    5879 
    5880 
    5881 
    5882  <br>
    5883 
    5884 
    5885 
    5886 
    5887 
    5888 
    5889 
    5890 If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
    5891 or <a href="#bc_ns">bc_ns</a>),
    5892 this parameter gives the gridpoint number (counted horizontally from
    5893 the inflow)&nbsp; from which on perturbations are imposed on the
    5894 horizontal velocity field. Perturbations must be switched on with
    5895 parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
    5896 
    5897 
    5898 
    5899 
    5900 
    5901 
    5902 
    5903     </tr>
    5904 
    5905 
    5906 
    5907 
    5908 
    5909 
    5910  <tr>
    5911 
    5912 
    5913 
    5914 
    5915 
    5916 
    5917  <td style="vertical-align: top;"><a name="inflow_disturbance_end"></a><b>inflow_disturbance_<br>
    5918 
    5919 
    5920 
    5921 
    5922 
    5923 
    5924 
    5925 end</b></td>
    5926 
    5927 
    5928 
    5929 
    5930 
    5931 
    5932  <td style="vertical-align: top;">I</td>
    5933 
    5934 
    5935 
    5936 
    5937 
    5938 
    5939 
    5940       <td style="vertical-align: top;"><span style="font-style: italic;">MIN(100,</span><br style="font-style: italic;">
    5941 
    5942 
    5943 
    5944 
    5945 
    5946 
    5947  <span style="font-style: italic;">3/4*nx or</span><br style="font-style: italic;">
    5948 
    5949 
    5950 
    5951 
    5952 
    5953 
    5954  <span style="font-style: italic;">3/4*ny)</span></td>
    5955 
    5956 
    5957 
    5958 
    5959 
    5960 
    5961  <td style="vertical-align: top;">Upper
    5962 limit of the horizontal range for which random perturbations are
    5963 to be imposed on the horizontal velocity field (gridpoints).<br>
    5964 
    5965 
    5966 
    5967 
    5968 
    5969 
    5970  <br>
    5971 
    5972 
    5973 
    5974 
    5975 
    5976 
    5977 
    5978 If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
    5979 or <a href="#bc_ns">bc_ns</a>),
    5980 this parameter gives the gridpoint number (counted horizontally from
    5981 the inflow)&nbsp; unto which perturbations are imposed on the
    5982 horizontal
    5983 velocity field. Perturbations must be switched on with parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
    5984 
    5985 
    5986 
    5987 
    5988 
    5989 
    5990 
    5991     </tr>
    5992 
    5993 
    5994 
    5995 
    5996 
    5997 
    5998  <tr>
    5999 
    6000 
    6001 
    6002 
    6003 
    6004 
    6005  <td style="vertical-align: top;">
    6006      
    6007      
    6008      
    6009      
    6010      
    6011      
    6012       <p><a name="initializing_actions"></a><b>initializing_actions</b></p>
    6013 
    6014 
    6015 
    6016 
    6017 
    6018 
    6019 
    6020       </td>
    6021 
    6022 
    6023 
    6024 
    6025 
    6026 
    6027  <td style="vertical-align: top;">C * 100</td>
    6028 
    6029 
    6030 
    6031 
    6032 
    6033 
    6034 
    6035       <td style="vertical-align: top;"><br>
    6036 
    6037 
    6038 
    6039 
    6040 
    6041 
    6042  </td>
    6043 
    6044 
    6045 
    6046 
    6047 
    6048 
    6049  <td style="vertical-align: top;">
    6050      
    6051      
    6052      
    6053      
    6054      
    6055      
    6056       <p style="font-style: normal;">Initialization actions
    6057 to be carried out.&nbsp; </p>
    6058 
    6059 
    6060 
    6061 
    6062 
    6063 
    6064  
    6065      
    6066      
    6067      
    6068      
    6069      
    6070      
    6071       <p style="font-style: normal;">This parameter does not have a
    6072 default value and therefore must be assigned with each model run. For
    6073 restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
    6074 must be set. For the initial run of a job chain the following values
    6075 are allowed:&nbsp; </p>
    6076 
    6077 
    6078 
    6079 
    6080 
    6081 
    6082  
    6083      
    6084      
    6085      
    6086      
    6087      
    6088      
    6089       <p style="font-style: normal;"><span style="font-style: italic;">'set_constant_profiles'</span>
    6090       </p>
    6091 
    6092 
    6093 
    6094 
    6095 
    6096 
    6097  
    6098      
    6099      
    6100      
    6101      
    6102      
    6103      
    6104       <ul>
    6105 
    6106 
    6107 
    6108 
    6109 
    6110 
    6111  
    6112        
    6113        
    6114        
    6115        
    6116        
    6117        
    6118         <p>A horizontal wind profile consisting
    6119 of linear sections (see <a href="#ug_surface">ug_surface</a>,
    6120         <a href="#ug_vertical_gradient">ug_vertical_gradient</a>,
    6121         <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
    6122 and <a href="#vg_surface">vg_surface</a>, <a href="#vg_vertical_gradient">vg_vertical_gradient</a>,
    6123         <a href="#vg_vertical_gradient_level">vg_vertical_gradient_level</a>,
    6124 respectively) as well as a vertical temperature (humidity) profile
    6125 consisting of
    6126 linear sections (see <a href="#pt_surface">pt_surface</a>,
    6127         <a href="#pt_vertical_gradient">pt_vertical_gradient</a>,
    6128         <a href="#q_surface">q_surface</a>
    6129 and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
    6130 are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
    6131 and K<sub>h</sub> are set to very small values because
    6132 otherwise no TKE
    6133 would be generated.</p>
    6134 
    6135 
    6136 
    6137 
    6138 
    6139 
    6140  
    6141      
    6142      
    6143      
    6144      
    6145      
    6146      
    6147       </ul>
    6148 
    6149 
    6150 
    6151 
    6152 
    6153 
    6154  
    6155      
    6156      
    6157      
    6158      
    6159      
    6160      
    6161       <p style="font-style: italic;">'set_1d-model_profiles' </p>
    6162 
    6163 
    6164 
    6165 
    6166 
    6167 
    6168 
    6169      
    6170      
    6171      
    6172      
    6173      
    6174      
    6175       <ul>
    6176 
    6177 
    6178 
    6179 
    6180 
    6181 
    6182  
    6183        
    6184        
    6185        
    6186        
    6187        
    6188        
    6189         <p>The arrays of the 3d-model are initialized with
    6190 the
    6191 (stationary) solution of the 1d-model. These are the variables e, kh,
    6192 km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
    6193 temperature (humidity) profile consisting of linear sections is set as
    6194 for 'set_constant_profiles' and assumed as constant in time within the
    6195 1d-model. For steering of the 1d-model a set of parameters with suffix
    6196 "_1d" (e.g. <a href="#end_time_1d">end_time_1d</a>,
    6197         <a href="#damp_level_1d">damp_level_1d</a>)
    6198 is available.</p>
    6199 
    6200 
    6201 
    6202 
    6203 
    6204 
    6205  
    6206      
    6207      
    6208      
    6209      
    6210      
    6211      
    6212       </ul>
    6213 
    6214 
    6215 
    6216 
    6217 
    6218 
    6219  
    6220      
    6221      
    6222      
    6223      
    6224      
    6225      
    6226       <p><span style="font-style: italic;">'by_user'</span></p>
    6227 
    6228 
    6229 
    6230 
    6231 
    6232 
    6233      
    6234      
    6235      
    6236      
    6237      
    6238      
    6239       <p style="margin-left: 40px;">The initialization of the arrays
    6240 of the 3d-model is under complete control of the user and has to be
    6241 done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
    6242 of the user-interface.<span style="font-style: italic;"></span></p>
    6243 
    6244 
    6245 
    6246 
    6247 
    6248 
    6249      
    6250      
    6251      
    6252      
    6253      
    6254      
    6255       <p><span style="font-style: italic;">'initialize_vortex'</span>
    6256       </p>
    6257 
    6258 
    6259 
    6260 
    6261 
    6262 
    6263  
    6264      
    6265      
    6266      
    6267      
    6268      
    6269      
    6270       <div style="margin-left: 40px;">The initial
    6271 velocity field of the
    6272 3d-model corresponds to a
    6273 Rankine-vortex with vertical axis. This setting may be used to test
    6274 advection schemes. Free-slip boundary conditions for u and v (see <a href="#bc_uv_b">bc_uv_b</a>, <a href="#bc_uv_t">bc_uv_t</a>)
    6275 are necessary. In order not to distort the vortex, an initial
    6276 horizontal wind profile constant
    6277 with height is necessary (to be set by <b>initializing_actions</b>
    6278 = <span style="font-style: italic;">'set_constant_profiles'</span>)
    6279 and some other conditions have to be met (neutral stratification,
    6280 diffusion must be
    6281 switched off, see <a href="#km_constant">km_constant</a>).
    6282 The center of the vortex is located at jc = (nx+1)/2. It
    6283 extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
    6284 and the exponentially decaying part ranges to 32 * <a href="#dx">dx</a>
    6285 (see init_rankine.f90). </div>
    6286 
    6287 
    6288 
    6289 
    6290 
    6291 
    6292  
    6293      
    6294      
    6295      
    6296      
    6297      
    6298      
    6299       <p><span style="font-style: italic;">'initialize_ptanom'</span>
    6300       </p>
    6301 
    6302 
    6303 
    6304 
    6305 
    6306 
    6307  
    6308      
    6309      
    6310      
    6311      
    6312      
    6313      
    6314       <ul>
    6315 
    6316 
    6317 
    6318 
    6319 
    6320 
    6321  
    6322        
    6323        
    6324        
    6325        
    6326        
    6327        
    6328         <p>A 2d-Gauss-like shape disturbance
    6329 (x,y) is added to the
    6330 initial temperature field with radius 10.0 * <a href="#dx">dx</a>
    6331 and center at jc = (nx+1)/2. This may be used for tests of scalar
    6332 advection schemes
    6333 (see <a href="#scalar_advec">scalar_advec</a>).
    6334 Such tests require a horizontal wind profile constant with hight and
    6335 diffusion
    6336 switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
    6337 Additionally, the buoyancy term
    6338 must be switched of in the equation of motion&nbsp; for w (this
    6339 requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
    6340 source code of <span style="font-family: monospace;">prognostic_equations.f90</span>).</p></ul>
    6341 
    6342 
    6343 
    6344 
    6345 
    6346 
    6347  
    6348      
    6349      
    6350      
    6351      
    6352      
    6353      
    6354       <p style="font-style: italic;">'cyclic_fill'</p><p style="font-style: normal; margin-left: 40px;">Here,
    6355 3d-data from a precursor run are read by the initial (main) run. The
    6356 precursor run is allowed to have a smaller domain along x and y
    6357 compared with the main run. Also, different numbers of processors can
    6358 be used for these two runs. Limitations are that the precursor run must
    6359 use cyclic horizontal boundary conditions and that the number of vertical grid points, <a href="#nz">nz</a>, must be same for the precursor run and the main run. If the total domain of the main run is larger than that of the precursor
    6360 run, the domain is filled by cyclic repetition&nbsp;of the (cyclic)
    6361 precursor data. This initialization method is recommended if a
    6362 turbulent inflow is used (see <a href="chapter_4.1.html#turbulent_inflow">turbulent_inflow</a>). 3d-data must be made available to the run by activating an appropriate file connection statement for local file BININ. See <a href="chapter_3.9.html">chapter 3.9</a> for more details, where usage of a turbulent inflow is explained. </p><p style="font-style: normal;">Values may be
    6363 combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
    6364 initialize_vortex'</span>, but the values of <span style="font-style: italic;">'set_constant_profiles'</span>,
    6365       <span style="font-style: italic;">'set_1d-model_profiles'</span>
    6366 , and <span style="font-style: italic;">'by_user'</span>
    6367 must not be given at the same time.</p>
    6368 
    6369 
    6370 
    6371 
    6372 
    6373 
    6374  
    6375      
    6376      
    6377      
    6378      
    6379      
    6380      
    6381      
    6382 
    6383 
    6384 
    6385 
    6386 
    6387 
    6388  </td>
    6389 
    6390 
    6391 
    6392 
    6393 
    6394 
    6395  </tr>
    6396 
    6397 
    6398 
    6399 
    6400 
    6401 
    6402 
    6403     <tr>
    6404 
    6405 
    6406 
    6407 
    6408 
    6409 
    6410  <td style="vertical-align: top;">
    6411      
    6412      
    6413      
    6414      
    6415      
    6416      
    6417       <p><a name="km_constant"></a><b>km_constant</b></p>
    6418 
    6419 
    6420 
    6421 
    6422 
    6423 
    6424 
    6425       </td>
    6426 
    6427 
    6428 
    6429 
    6430 
    6431 
    6432  <td style="vertical-align: top;">R</td>
    6433 
    6434 
    6435 
    6436 
    6437 
    6438 
    6439 
    6440       <td style="vertical-align: top;"><i>variable<br>
    6441 
    6442 
    6443 
    6444 
    6445 
    6446 
    6447 
    6448 (computed from TKE)</i></td>
    6449 
    6450 
    6451 
    6452 
    6453 
    6454 
    6455  <td style="vertical-align: top;">
    6456      
    6457      
    6458      
    6459      
    6460      
    6461      
    6462       <p>Constant eddy
    6463 diffusivities are used (laminar
    6464 simulations).&nbsp; </p>
    6465 
    6466 
    6467 
    6468 
    6469 
    6470 
    6471  
    6472      
    6473      
    6474      
    6475      
    6476      
    6477      
    6478       <p>If this parameter is
    6479 specified, both in the 1d and in the
    6480 3d-model constant values for the eddy diffusivities are used in
    6481 space and time with K<sub>m</sub> = <b>km_constant</b>
    6482 and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
    6483 The prognostic equation for the subgrid-scale TKE is switched off.
    6484 Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
    6485 switched off.</p>
    6486 
    6487 
    6488 
    6489 
    6490 
    6491 
    6492  </td>
    6493 
    6494 
    6495 
    6496 
    6497 
    6498 
    6499  </tr>
    6500 
    6501 
    6502 
    6503 
    6504 
    6505 
    6506  <tr>
    6507 
    6508 
    6509 
    6510 
    6511 
    6512 
    6513  <td style="vertical-align: top;">
    6514      
    6515      
    6516      
    6517      
    6518      
    6519      
    6520       <p><a name="km_damp_max"></a><b>km_damp_max</b></p>
    6521 
    6522 
    6523 
    6524 
    6525 
    6526 
    6527 
    6528       </td>
    6529 
    6530 
    6531 
    6532 
    6533 
    6534 
    6535  <td style="vertical-align: top;">R</td>
    6536 
    6537 
    6538 
    6539 
    6540 
    6541 
    6542 
    6543       <td style="vertical-align: top;"><span style="font-style: italic;">0.5*(dx
    6544 or dy)</span></td>
    6545 
    6546 
    6547 
    6548 
    6549 
    6550 
    6551  <td style="vertical-align: top;">Maximum
    6552 diffusivity used for filtering the velocity field in the vicinity of
    6553 the outflow (in m<sup>2</sup>/s).<br>
    6554 
    6555 
    6556 
    6557 
    6558 
    6559 
    6560  <br>
    6561 
    6562 
    6563 
    6564 
    6565 
    6566 
    6567 
    6568 When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
    6569 or <a href="#bc_ns">bc_ns</a>),
    6570 a smoothing has to be applied to the
    6571 velocity field in the vicinity of the outflow in order to suppress any
    6572 reflections of outgoing disturbances. Smoothing is done by increasing
    6573 the eddy diffusivity along the horizontal direction which is
    6574 perpendicular to the outflow boundary. Only velocity components
    6575 parallel to the outflow boundary are filtered (e.g. v and w, if the
    6576 outflow is along x). Damping is applied from the bottom to the top of
    6577 the domain.<br>
    6578 
    6579 
    6580 
    6581 
    6582 
    6583 
    6584  <br>
    6585 
    6586 
    6587 
    6588 
    6589 
    6590 
    6591 
    6592 The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
    6593 which defines the number of gridpoints (counted from the outflow
    6594 boundary) from where on the smoothing is applied. Starting from that
    6595 point, the eddy diffusivity is linearly increased (from zero to its
    6596 maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
    6597 until half of the damping range width, from where it remains constant
    6598 up to the outflow boundary. If at a certain grid point the eddy
    6599 diffusivity calculated from the flow field is larger than as described
    6600 above, it is used instead.<br>
    6601 
    6602 
    6603 
    6604 
    6605 
    6606 
    6607  <br>
    6608 
    6609 
    6610 
    6611 
    6612 
    6613 
    6614 
    6615 The default value of <span style="font-weight: bold;">km_damp_max</span>
    6616 has been empirically proven to be sufficient.</td>
    6617 
    6618 
    6619 
    6620 
    6621 
    6622 
    6623  </tr>
    6624 
    6625 
    6626 
    6627 
    6628 
    6629 
    6630  <tr>
    6631 
    6632       <td style="vertical-align: top;"><a name="lad_surface"></a><span style="font-weight: bold;">lad_surface</span></td>
    6633 
    6634       <td style="vertical-align: top;">R</td>
    6635 
    6636       <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
    6637 
    6638       <td style="vertical-align: top;">Surface value of the leaf area density (in m<sup>2</sup>/m<sup>3</sup>).<br>
    6639 
    6640       <br>
    6641 
    6642 This
    6643 parameter assigns the value of the leaf area density <span style="font-weight: bold;">lad</span> at the surface (k=0)<b>.</b> Starting from this value,
    6644 the leaf area density profile is constructed with <a href="#lad_vertical_gradient">lad_vertical_gradient</a>
    6645 and <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level
    6646       </a>.</td>
    6647 
    6648     </tr>
    6649 
    6650     <tr>
    6651 
    6652       <td style="vertical-align: top;"><a name="lad_vertical_gradient"></a><span style="font-weight: bold;">lad_vertical_gradient</span></td>
    6653 
    6654       <td style="vertical-align: top;">R (10)</td>
    6655 
    6656       <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
    6657 
    6658       <td style="vertical-align: top;">Gradient(s) of the leaf area density (in&nbsp;m<sup>2</sup>/m<sup>4</sup>).<br>
    6659 
    6660       <br>
    6661 
    6662      
    6663       <p>This leaf area density gradient
    6664 holds starting from the height&nbsp;
    6665 level defined by <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level</a>
    6666 (precisely: for all uv levels k where zu(k) &gt; lad_vertical_gradient_level, lad(k) is set: lad(k) = lad(k-1) + dzu(k) * <b>lad_vertical_gradient</b>)
    6667 up to the level defined by <a href="#pch_index">pch_index</a>. Above that level lad(k) will automatically set to 0.0. A total of 10 different gradients for 11 height intervals (10 intervals
    6668 if <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level</a>(1)
    6669 = <i>0.0</i>) can be assigned. The leaf area density at the surface is
    6670 assigned via <a href="#lad_surface">lad_surface</a>.&nbsp;
    6671       </p>
    6672 
    6673       </td>
    6674 
    6675     </tr>
    6676 
    6677     <tr>
    6678 
    6679       <td style="vertical-align: top;"><a name="lad_vertical_gradient_level"></a><span style="font-weight: bold;">lad_vertical_gradient_level</span></td>
    6680 
    6681       <td style="vertical-align: top;">R (10)</td>
    6682 
    6683       <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
    6684 
    6685       <td style="vertical-align: top;">Height level from which on the&nbsp;gradient
    6686 of the leaf area density defined by <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level</a>
    6687 is effective (in m).<br>
    6688 
    6689       <br>
    6690 
    6691 The height levels have to be assigned in ascending order. The
    6692 default values result in a leaf area density that is constant with height uup to the top of the plant canopy layer defined by <a href="#pch_index">pch_index</a>. For the piecewise construction of temperature profiles see <a href="#lad_vertical_gradient">lad_vertical_gradient</a>.</td>
    6693 
    6694     </tr>
    6695 
    6696     <tr>
    6697 
    6698       <td style="vertical-align: top;"><a name="leaf_surface_concentration"></a><b>leaf_surface_concentration</b></td>
    6699 
    6700       <td style="vertical-align: top;">R</td>
    6701 
    6702       <td style="vertical-align: top;"><i>0.0</i></td>
    6703 
    6704       <td style="vertical-align: top;">Concentration of a passive scalar at the surface of a leaf (in K m/s).<br>
    6705 
    6706 
    6707       <br>
    6708 
    6709 
    6710 This parameter is only of importance in cases in that both, <a href="#plant_canopy">plant_canopy</a> and <a href="#passive_scalar">passive_scalar</a>, are set <span style="font-style: italic;">.T.</span>.
    6711 The value of the concentration of a passive scalar at the surface of a
    6712 leaf is required for the parametrisation of the sources and sinks of
    6713 scalar concentration due to the canopy.</td>
    6714 
    6715     </tr>
    6716 
    6717     <tr>
    6718 
    6719 
    6720 
    6721 
    6722 
    6723 
    6724 
    6725       <td style="vertical-align: top;">
    6726      
    6727      
    6728      
    6729      
    6730      
    6731      
    6732       <p><a name="long_filter_factor"></a><b>long_filter_factor</b></p>
    6733 
    6734 
    6735 
    6736 
    6737 
    6738 
    6739 
    6740       </td>
    6741 
    6742 
    6743 
    6744 
    6745 
    6746 
    6747  <td style="vertical-align: top;">R</td>
    6748 
    6749 
    6750 
    6751 
    6752 
    6753 
    6754 
    6755       <td style="vertical-align: top;"><i>0.0</i></td>
    6756 
    6757 
    6758 
    6759 
    6760 
    6761 
    6762 
    6763       <td style="vertical-align: top;">
    6764      
    6765      
    6766      
    6767      
    6768      
    6769      
    6770       <p>Filter factor
    6771 for the so-called Long-filter.<br>
    6772 
    6773 
    6774 
    6775 
    6776 
    6777 
    6778  </p>
    6779 
    6780 
    6781 
    6782 
    6783 
    6784 
    6785  
    6786      
    6787      
    6788      
    6789      
    6790      
    6791      
    6792       <p><br>
    6793 
    6794 
    6795 
    6796 
    6797 
    6798 
    6799 
    6800 This filter very efficiently
    6801 eliminates 2-delta-waves sometimes cauesed by the upstream-spline
    6802 scheme (see Mahrer and
    6803 Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
    6804 directions in space. A value of <b>long_filter_factor</b>
    6805 = <i>0.01</i>
    6806 sufficiently removes the small-scale waves without affecting the
    6807 longer waves.<br>
    6808 
    6809 
    6810 
    6811 
    6812 
    6813 
    6814  </p>
    6815 
    6816 
    6817 
    6818 
    6819 
    6820 
    6821  
    6822      
    6823      
    6824      
    6825      
    6826      
    6827      
    6828       <p>By default, the filter is
    6829 switched off (= <i>0.0</i>).
    6830 It is exclusively applied to the tendencies calculated by the
    6831 upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
    6832 and <a href="#scalar_advec">scalar_advec</a>),
    6833 not to the prognostic variables themselves. At the bottom and top
    6834 boundary of the model domain the filter effect for vertical
    6835 2-delta-waves is reduced. There, the amplitude of these waves is only
    6836 reduced by approx. 50%, otherwise by nearly 100%.&nbsp; <br>
    6837 
    6838 
    6839 
    6840 
    6841 
    6842 
    6843 
    6844 Filter factors with values &gt; <i>0.01</i> also
    6845 reduce the amplitudes
    6846 of waves with wavelengths longer than 2-delta (see the paper by Mahrer
    6847 and
    6848 Pielke, quoted above). </p>
    6849 
    6850 
    6851 
    6852 
    6853 
    6854 
    6855  </td>
    6856 
    6857 
    6858 
    6859 
    6860 
    6861 
    6862  </tr>
    6863 
    6864 
    6865 
    6866 
    6867 
    6868 
    6869  <tr>
    6870 
    6871 
    6872 
    6873 
    6874 
    6875 
    6876       <td style="vertical-align: top;"><a name="loop_optimization"></a><span style="font-weight: bold;">loop_optimization</span></td>
    6877 
    6878 
    6879 
    6880 
    6881 
    6882 
    6883       <td style="vertical-align: top;">C*16</td>
    6884 
    6885 
    6886 
    6887 
    6888 
    6889 
    6890       <td style="vertical-align: top;"><span style="font-style: italic;">see right</span></td>
    6891 
    6892 
    6893 
    6894 
    6895 
    6896 
    6897       <td>Method used to optimize loops for solving the prognostic equations .<br>
    6898 
    6899 
    6900 
    6901 
    6902 
    6903 
    6904       <br>
    6905 
    6906 
    6907 
    6908 
    6909 
    6910 
    6911 By
    6912 default, the optimization method depends on the host on which PALM is
    6913 running. On machines with vector-type CPUs, single 3d-loops are used to
    6914 calculate each tendency term of each prognostic equation, while on all
    6915 other machines, all prognostic equations are solved within one big loop
    6916 over the two horizontal indices<span style="font-family: Courier New,Courier,monospace;"> i </span>and<span style="font-family: Courier New,Courier,monospace;"> j </span>(giving a good cache uitilization).<br>
    6917 
    6918 
    6919 
    6920 
    6921 
    6922 
    6923       <br>
    6924 
    6925 
    6926 
    6927 
    6928 
    6929 
    6930 The default behaviour can be changed by setting either <span style="font-weight: bold;">loop_optimization</span> = <span style="font-style: italic;">'vector'</span> or <span style="font-weight: bold;">loop_optimization</span> = <span style="font-style: italic;">'cache'</span>.</td>
    6931 
    6932 
    6933 
    6934 
    6935 
    6936 
    6937     </tr>
    6938 
    6939 
    6940 
    6941 
    6942 
    6943 
    6944     <tr>
    6945 
    6946 
    6947 
    6948 
    6949 
    6950 
    6951 
    6952       <td style="vertical-align: top;"><a name="mixing_length_1d"></a><span style="font-weight: bold;">mixing_length_1d</span><br>
    6953 
    6954 
    6955 
    6956 
    6957 
    6958 
    6959 
    6960       </td>
    6961 
    6962 
    6963 
    6964 
    6965 
    6966 
    6967  <td style="vertical-align: top;">C*20<br>
    6968 
    6969 
    6970 
    6971 
    6972 
    6973 
    6974 
    6975       </td>
    6976 
    6977 
    6978 
    6979 
    6980 
    6981 
    6982  <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
    6983 
    6984 
    6985 
    6986 
    6987 
    6988 
    6989  <span style="font-style: italic;">model'</span><br>
    6990 
    6991 
    6992 
    6993 
    6994 
    6995 
    6996  </td>
    6997 
    6998 
    6999 
    7000 
    7001 
    7002 
    7003 
    7004       <td style="vertical-align: top;">Mixing length used in the
    7005 1d-model.<br>
    7006 
    7007 
    7008 
    7009 
    7010 
    7011 
    7012  <br>
    7013 
    7014 
    7015 
    7016 
    7017 
    7018 
    7019 
    7020 By default the mixing length is calculated as in the 3d-model (i.e. it
    7021 depends on the grid spacing).<br>
    7022 
    7023 
    7024 
    7025 
    7026 
    7027 
    7028  <br>
    7029 
    7030 
    7031 
    7032 
    7033 
    7034 
    7035 
    7036 By setting <span style="font-weight: bold;">mixing_length_1d</span>
    7037 = <span style="font-style: italic;">'blackadar'</span>,
    7038 the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
    7039 kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).<br>
    7040 
    7041 
    7042 
    7043 
    7044 
    7045 
    7046 
    7047       </td>
    7048 
    7049 
    7050 
    7051 
    7052 
    7053 
    7054  </tr>
    7055 
    7056 
    7057 
    7058 
    7059 
    7060 
    7061  
    7062 
    7063 
    7064 
    7065 
    7066 
    7067 
    7068 
    7069     <tr>
    7070 
    7071 
    7072 
    7073 
    7074 
    7075 
    7076  <td style="vertical-align: top;">
    7077      
    7078      
    7079      
    7080      
    7081      
    7082      
    7083       <p><a name="momentum_advec"></a><b>momentum_advec</b></p>
    7084 
    7085 
    7086 
    7087 
    7088 
    7089 
    7090 
    7091       </td>
    7092 
    7093 
    7094 
    7095 
    7096 
    7097 
    7098  <td style="vertical-align: top;">C * 10</td>
    7099 
    7100 
    7101 
    7102 
    7103 
    7104 
    7105 
    7106       <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
    7107 
    7108 
    7109 
    7110 
    7111 
    7112 
    7113 
    7114       <td style="vertical-align: top;">
    7115      
    7116      
    7117      
    7118      
    7119      
    7120      
    7121       <p>Advection
    7122 scheme to be used for the momentum equations.<br>
    7123 
    7124 
    7125 
    7126 
    7127 
    7128 
    7129  <br>
    7130 
    7131 
    7132 
    7133 
    7134 
    7135 
    7136 
    7137 The user can choose between the following schemes:<br>
    7138 
    7139 
    7140 
    7141 
    7142 
    7143 
    7144 
    7145 &nbsp;<br>
    7146 
    7147 
    7148 
    7149 
    7150 
    7151 
    7152  <br>
    7153 
    7154 
    7155 
    7156 
    7157 
    7158 
    7159  <span style="font-style: italic;">'pw-scheme'</span><br>
    7160 
    7161 
    7162 
    7163 
    7164 
    7165 
    7166 
    7167       </p>
    7168 
    7169 
    7170 
    7171 
    7172 
    7173 
    7174  
    7175      
    7176      
    7177      
    7178      
    7179      
    7180      
    7181       <div style="margin-left: 40px;">The scheme of
    7182 Piascek and
    7183 Williams (1970, J. Comp. Phys., 6,
    7184 392-405) with central differences in the form C3 is used.<br>
    7185 
    7186 
    7187 
    7188 
    7189 
    7190 
    7191 
    7192 If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
    7193 = <span style="font-style: italic;">'leapfrog+euler'</span>
    7194 the
    7195 advection scheme is - for the Euler-timestep - automatically switched
    7196 to an upstream-scheme.<br>
    7197 
    7198 
    7199 
    7200 
    7201 
    7202 
    7203  </div>
    7204 
    7205 
    7206 
    7207 
    7208 
    7209 
    7210  
    7211      
    7212      
    7213      
    7214      
    7215      
    7216      
    7217       <p> </p>
    7218 
    7219 
    7220 
    7221 
    7222 
    7223 
    7224  
    7225      
    7226      
    7227      
    7228      
    7229      
    7230      
    7231       <p><span style="font-style: italic;">'ups-scheme'</span><br>
    7232 
    7233 
    7234 
    7235 
    7236 
    7237 
    7238 
    7239       </p>
    7240 
    7241 
    7242 
    7243 
    7244 
    7245 
    7246  
    7247      
    7248      
    7249      
    7250      
    7251      
    7252      
    7253       <div style="margin-left: 40px;">The
    7254 upstream-spline scheme is
    7255 used
    7256 (see Mahrer and Pielke,
    7257 1978: Mon. Wea. Rev., 106, 818-830). In opposite to the
    7258 Piascek-Williams scheme, this is characterized by much better numerical
    7259 features (less numerical diffusion, better preservation of flow
    7260 structures, e.g. vortices), but computationally it is much more
    7261 expensive. In
    7262 addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
    7263 = <span style="font-style: italic;">'</span><i>euler'</i>),
    7264 i.e. the
    7265 timestep accuracy is only of first order.
    7266 For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
    7267 should then also be carried out with the upstream-spline scheme,
    7268 because otherwise the scalar variables would
    7269 be subject to large numerical diffusion due to the upstream
    7270 scheme.&nbsp; </div>
    7271 
    7272 
    7273 
    7274 
    7275 
    7276 
    7277  
    7278      
    7279      
    7280      
    7281      
    7282      
    7283      
    7284       <p style="margin-left: 40px;">Since
    7285 the cubic splines used tend
    7286 to overshoot under
    7287 certain circumstances, this effect must be adjusted by suitable
    7288 filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
    7289       <a href="#long_filter_factor">long_filter_factor</a>,
    7290       <a href="#ups_limit_pt">ups_limit_pt</a>, <a href="#ups_limit_u">ups_limit_u</a>, <a href="#ups_limit_v">ups_limit_v</a>, <a href="#ups_limit_w">ups_limit_w</a>).
    7291 This is always neccessary for runs with stable stratification,
    7292 even if this stratification appears only in parts of the model domain.<br>
    7293 
    7294 
    7295 
    7296 
    7297 
    7298 
    7299 
    7300       </p>
    7301 
    7302 
    7303 
    7304 
    7305 
    7306 
    7307  
    7308      
    7309      
    7310      
    7311      
    7312      
    7313      
    7314       <div style="margin-left: 40px;">With stable
    7315 stratification the
    7316 upstream-spline scheme also
    7317 produces gravity waves wi