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1  % $Header$  % $Header$
2  % $Name$  % $Name$
3    
4  \section{Getting started}  %\section{Getting started}
5    
6  In this part, we describe how to use the model. In the first section, we  In this section, we describe how to use the model. In the first
7  provide enough information to help you get started with the model. We  section, we provide enough information to help you get started with
8  believe the best way to familiarize yourself with the model is to run the  the model. We believe the best way to familiarize yourself with the
9  case study examples provided with the base version. Information on how to  model is to run the case study examples provided with the base
10  obtain, compile, and run the code is found there as well as a brief  version. Information on how to obtain, compile, and run the code is
11  description of the model structure directory and the case study examples.  found there as well as a brief description of the model structure
12  The latter and the code structure are described more fully in sections 2 and  directory and the case study examples.  The latter and the code
13  3, respectively. In section 4, we provide information on how to customize  structure are described more fully in chapters
14  the code when you are ready to try implementing the configuration you have  \ref{chap:discretization} and \ref{chap:sarch}, respectively. Here, in
15  in mind.  this section, we provide information on how to customize the code when
16    you are ready to try implementing the configuration you have in mind.
17    
18  \subsection{Obtaining the code}  \section{Where to find information}
19    \label{sect:whereToFindInfo}
20    
21  The reference web site for the model is:  A web site is maintained for release 2 (``Pelican'') of MITgcm:
22    \begin{rawhtml} <A href=http://mitgcm.org/pelican/ target="idontexist"> \end{rawhtml}
23  \begin{verbatim}  \begin{verbatim}
24  http://mitgcm.org  http://mitgcm.org/pelican
25  \end{verbatim}  \end{verbatim}
26    \begin{rawhtml} </A> \end{rawhtml}
27  On this site, you can download the model as well as find useful information,  Here you will find an on-line version of this document, a
28  some of which might overlap with what is written here. There is also a  ``browsable'' copy of the code and a searchable database of the model
29  support news group for the model located at (send your message to \texttt{%  and site, as well as links for downloading the model and
30  support@mitgcm.org}):  documentation, to data-sources, and other related sites.
31    
32    There is also a web-archived support mailing list for the model that
33    you can email at \texttt{MITgcm-support@mitgcm.org} or browse at:
34    \begin{rawhtml} <A href=http://mitgcm.org/mailman/listinfo/mitgcm-support/ target="idontexist"> \end{rawhtml}
35    \begin{verbatim}
36    http://mitgcm.org/mailman/listinfo/mitgcm-support/
37    http://mitgcm.org/pipermail/mitgcm-support/
38    \end{verbatim}
39    \begin{rawhtml} </A> \end{rawhtml}
40    Essentially all of the MITgcm web pages can be searched using a
41    popular web crawler such as Google or through our own search facility:
42    \begin{rawhtml} <A href=http://mitgcm.org/mailman/htdig/ target="idontexist"> \end{rawhtml}
43  \begin{verbatim}  \begin{verbatim}
44  news://mitgcm.org/mitgcm.support  http://mitgcm.org/htdig/
45  \end{verbatim}  \end{verbatim}
46    \begin{rawhtml} </A> \end{rawhtml}
47    %%% http://www.google.com/search?q=hydrostatic+site%3Amitgcm.org
48    
49    
50    
51    \section{Obtaining the code}
52    \label{sect:obtainingCode}
53    
54    MITgcm can be downloaded from our system by following
55    the instructions below. As a courtesy we ask that you send e-mail to us at
56    \begin{rawhtml} <A href=mailto:MITgcm-support@mitgcm.org> \end{rawhtml}
57    MITgcm-support@mitgcm.org
58    \begin{rawhtml} </A> \end{rawhtml}
59    to enable us to keep track of who's using the model and in what application.
60    You can download the model two ways:
61    
62    \begin{enumerate}
63    \item Using CVS software. CVS is a freely available source code management
64    tool. To use CVS you need to have the software installed. Many systems
65    come with CVS pre-installed, otherwise good places to look for
66    the software for a particular platform are
67    \begin{rawhtml} <A href=http://www.cvshome.org/ target="idontexist"> \end{rawhtml}
68    cvshome.org
69    \begin{rawhtml} </A> \end{rawhtml}
70    and
71    \begin{rawhtml} <A href=http://www.wincvs.org/ target="idontexist"> \end{rawhtml}
72    wincvs.org
73    \begin{rawhtml} </A> \end{rawhtml}
74    .
75    
76    \item Using a tar file. This method is simple and does not
77    require any special software. However, this method does not
78    provide easy support for maintenance updates.
79    
80    \end{enumerate}
81    
82  If CVS is available on your system, we strongly encourage you to use it. CVS  If CVS is available on your system, we strongly encourage you to use it. CVS
83  provides an efficient and elegant way of organizing your code and keeping  provides an efficient and elegant way of organizing your code and keeping
84  track of your changes. If CVS is not available on your machine, you can also  track of your changes. If CVS is not available on your machine, you can also
85  download a tar file.  download a tar file.
86    
87  \subsubsection{Using CVS}  Before you can use CVS, the following environment variable(s) should
88    be set within your shell.  For a csh or tcsh shell, put the following
89    \begin{verbatim}
90    % setenv CVSROOT :pserver:cvsanon@mitgcm.org:/u/gcmpack
91    \end{verbatim}
92    in your .cshrc or .tcshrc file.  For bash or sh shells, put:
93    \begin{verbatim}
94    % export CVSROOT=':pserver:cvsanon@mitgcm.org:/u/gcmpack'
95    \end{verbatim}
96    in your .profile or .bashrc file.
97    
98  Before you can use CVS, the following environment variable has to be set in  
99  your .cshrc or .tcshrc:  To get MITgcm through CVS, first register with the MITgcm CVS server
100    using command:
101  \begin{verbatim}  \begin{verbatim}
 % setenv CVSROOT :pserver:cvsanon@mitgcm.org:/u/u0/gcmpack  
102  % cvs login ( CVS password: cvsanon )  % cvs login ( CVS password: cvsanon )
103  \end{verbatim}  \end{verbatim}
104    You only need to do a ``cvs login'' once.
105    
106  You only need to do ``cvs login'' once. To obtain the source for the release:  To obtain the latest sources type:
107  \begin{verbatim}  \begin{verbatim}
108  % cvs co -d directory -P -r release1 MITgcmUV  % cvs co MITgcm
109  \end{verbatim}  \end{verbatim}
110    or to get a specific release type:
 This creates a directory called \textit{directory}. If \textit{directory}  
 exists this command updates your code based on the repository. Each  
 directory in the source tree contains a directory \textit{CVS}. This  
 information is required by CVS to keep track of your file versions with  
 respect to the repository. Don't edit the files in \textit{CVS}! To obtain a  
 different \textit{version} that is not the latest source:  
111  \begin{verbatim}  \begin{verbatim}
112  % cvs co -d directory -P -r version MITgcm  % cvs co -P -r checkpoint52i_post  MITgcm
113  \end{verbatim}  \end{verbatim}
114  or the latest development version:  The MITgcm web site contains further directions concerning the source
115    code and CVS.  It also contains a web interface to our CVS archive so
116    that one may easily view the state of files, revisions, and other
117    development milestones:
118    \begin{rawhtml} <A href=''http://mitgcm.org/download'' target="idontexist"> \end{rawhtml}
119  \begin{verbatim}  \begin{verbatim}
120  % cvs co -d directory -P MITgcm  http://mitgcm.org/source_code.html
121  \end{verbatim}  \end{verbatim}
122    \begin{rawhtml} </A> \end{rawhtml}
123    
 \subsubsection{other methods}  
124    
125  You can download the model as a tar file from the reference web site at:  The checkout process creates a directory called \textit{MITgcm}. If
126    the directory \textit{MITgcm} exists this command updates your code
127    based on the repository. Each directory in the source tree contains a
128    directory \textit{CVS}. This information is required by CVS to keep
129    track of your file versions with respect to the repository. Don't edit
130    the files in \textit{CVS}!  You can also use CVS to download code
131    updates.  More extensive information on using CVS for maintaining
132    MITgcm code can be found
133    \begin{rawhtml} <A href=''http://mitgcm.org/usingcvstoget.html'' target="idontexist"> \end{rawhtml}
134    here
135    \begin{rawhtml} </A> \end{rawhtml}
136    .
137    
138    
139    \paragraph*{Conventional download method}
140    \label{sect:conventionalDownload}
141    
142    If you do not have CVS on your system, you can download the model as a
143    tar file from the web site at:
144    \begin{rawhtml} <A href=http://mitgcm.org/download target="idontexist"> \end{rawhtml}
145  \begin{verbatim}  \begin{verbatim}
146  http://mitgcm.org/download/  http://mitgcm.org/download/
147  \end{verbatim}  \end{verbatim}
148    \begin{rawhtml} </A> \end{rawhtml}
149  \subsection{Model and directory structure}  The tar file still contains CVS information which we urge you not to
150    delete; even if you do not use CVS yourself the information can help
151  The ``numerical'' model is contained within a execution environment support  us if you should need to send us your copy of the code.  If a recent
152  wrapper. This wrapper is designed to provide a general framework for  tar file does not exist, then please contact the developers through
153  grid-point models. MITgcmUV is a specific numerical model that uses the  the
154  framework. Under this structure the model is split into execution  \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
155  environment support code and conventional numerical model code. The  MITgcm-support@mitgcm.org
156  execution environment support code is held under the \textit{eesupp}  \begin{rawhtml} </A> \end{rawhtml}
157  directory. The grid point model code is held under the \textit{model}  mailing list.
158  directory. Code execution actually starts in the \textit{eesupp} routines  
159  and not in the \textit{model} routines. For this reason the top-level  \paragraph*{Upgrading from an earlier version}
160  \textit{MAIN.F} is in the \textit{eesupp/src} directory. In general,  
161  end-users should not need to worry about this level. The top-level routine  If you already have an earlier version of the code you can ``upgrade''
162  for the numerical part of the code is in \textit{model/src/THE\_MODEL\_MAIN.F%  your copy instead of downloading the entire repository again. First,
163  }. Here is a brief description of the directory structure of the model under  ``cd'' (change directory) to the top of your working copy:
164  the root tree (a detailed description is given in section 3: Code structure).  \begin{verbatim}
165    % cd MITgcm
166    \end{verbatim}
167    and then issue the cvs update command such as:
168    \begin{verbatim}
169    % cvs -q update -r checkpoint52i_post -d -P
170    \end{verbatim}
171    This will update the ``tag'' to ``checkpoint52i\_post'', add any new
172    directories (-d) and remove any empty directories (-P). The -q option
173    means be quiet which will reduce the number of messages you'll see in
174    the terminal. If you have modified the code prior to upgrading, CVS
175    will try to merge your changes with the upgrades. If there is a
176    conflict between your modifications and the upgrade, it will report
177    that file with a ``C'' in front, e.g.:
178    \begin{verbatim}
179    C model/src/ini_parms.F
180    \end{verbatim}
181    If the list of conflicts scrolled off the screen, you can re-issue the
182    cvs update command and it will report the conflicts. Conflicts are
183    indicated in the code by the delimites ``$<<<<<<<$'', ``======='' and
184    ``$>>>>>>>$''. For example,
185    {\small
186    \begin{verbatim}
187    <<<<<<< ini_parms.F
188         & bottomDragLinear,myOwnBottomDragCoefficient,
189    =======
190         & bottomDragLinear,bottomDragQuadratic,
191    >>>>>>> 1.18
192    \end{verbatim}
193    }
194    means that you added ``myOwnBottomDragCoefficient'' to a namelist at
195    the same time and place that we added ``bottomDragQuadratic''. You
196    need to resolve this conflict and in this case the line should be
197    changed to:
198    {\small
199    \begin{verbatim}
200         & bottomDragLinear,bottomDragQuadratic,myOwnBottomDragCoefficient,
201    \end{verbatim}
202    }
203    and the lines with the delimiters ($<<<<<<$,======,$>>>>>>$) be deleted.
204    Unless you are making modifications which exactly parallel
205    developments we make, these types of conflicts should be rare.
206    
207    \paragraph*{Upgrading to the current pre-release version}
208    
209    We don't make a ``release'' for every little patch and bug fix in
210    order to keep the frequency of upgrades to a minimum. However, if you
211    have run into a problem for which ``we have already fixed in the
212    latest code'' and we haven't made a ``tag'' or ``release'' since that
213    patch then you'll need to get the latest code:
214    \begin{verbatim}
215    % cvs -q update -A -d -P
216    \end{verbatim}
217    Unlike, the ``check-out'' and ``update'' procedures above, there is no
218    ``tag'' or release name. The -A tells CVS to upgrade to the
219    very latest version. As a rule, we don't recommend this since you
220    might upgrade while we are in the processes of checking in the code so
221    that you may only have part of a patch. Using this method of updating
222    also means we can't tell what version of the code you are working
223    with. So please be sure you understand what you're doing.
224    
225    \section{Model and directory structure}
226    
227    The ``numerical'' model is contained within a execution environment
228    support wrapper. This wrapper is designed to provide a general
229    framework for grid-point models. MITgcmUV is a specific numerical
230    model that uses the framework. Under this structure the model is split
231    into execution environment support code and conventional numerical
232    model code. The execution environment support code is held under the
233    \textit{eesupp} directory. The grid point model code is held under the
234    \textit{model} directory. Code execution actually starts in the
235    \textit{eesupp} routines and not in the \textit{model} routines. For
236    this reason the top-level \textit{MAIN.F} is in the
237    \textit{eesupp/src} directory. In general, end-users should not need
238    to worry about this level. The top-level routine for the numerical
239    part of the code is in \textit{model/src/THE\_MODEL\_MAIN.F}. Here is
240    a brief description of the directory structure of the model under the
241    root tree (a detailed description is given in section 3: Code
242    structure).
243    
244  \begin{itemize}  \begin{itemize}
 \item \textit{bin}: this directory is initially empty. It is the default  
 directory in which to compile the code.  
245    
246    \item \textit{bin}: this directory is initially empty. It is the
247      default directory in which to compile the code.
248      
249  \item \textit{diags}: contains the code relative to time-averaged  \item \textit{diags}: contains the code relative to time-averaged
250  diagnostics. It is subdivided into two subdirectories \textit{inc} and    diagnostics. It is subdivided into two subdirectories \textit{inc}
251  \textit{src} that contain include files (*.\textit{h} files) and fortran    and \textit{src} that contain include files (*.\textit{h} files) and
252  subroutines (*.\textit{F} files), respectively.    Fortran subroutines (*.\textit{F} files), respectively.
253    
254  \item \textit{doc}: contains brief documentation notes.  \item \textit{doc}: contains brief documentation notes.
255      
256  \item \textit{eesupp}: contains the execution environment source code. Also  \item \textit{eesupp}: contains the execution environment source code.
257  subdivided into two subdirectories \textit{inc} and \textit{src}.    Also subdivided into two subdirectories \textit{inc} and
258      \textit{src}.
259  \item \textit{exe}: this directory is initially empty. It is the default    
260  directory in which to execute the code.  \item \textit{exe}: this directory is initially empty. It is the
261      default directory in which to execute the code.
262  \item \textit{model}: this directory contains the main source code. Also    
263  subdivided into two subdirectories \textit{inc} and \textit{src}.  \item \textit{model}: this directory contains the main source code.
264      Also subdivided into two subdirectories \textit{inc} and
265  \item \textit{pkg}: contains the source code for the packages. Each package    \textit{src}.
266  corresponds to a subdirectory. For example, \textit{gmredi} contains the    
267  code related to the Gent-McWilliams/Redi scheme, \textit{aim} the code  \item \textit{pkg}: contains the source code for the packages. Each
268  relative to the atmospheric intermediate physics. The packages are described    package corresponds to a subdirectory. For example, \textit{gmredi}
269  in detail in section 3.    contains the code related to the Gent-McWilliams/Redi scheme,
270      \textit{aim} the code relative to the atmospheric intermediate
271  \item \textit{tools}: this directory contains various useful tools. For    physics. The packages are described in detail in section 3.
272  example, \textit{genmake} is a script written in csh (C-shell) that should    
273  be used to generate your makefile. The directory \textit{adjoint} contains  \item \textit{tools}: this directory contains various useful tools.
274  the makefile specific to the Tangent linear and Adjoint Compiler (TAMC) that    For example, \textit{genmake2} is a script written in csh (C-shell)
275  generates the adjoint code. The latter is described in details in part V.    that should be used to generate your makefile. The directory
276      \textit{adjoint} contains the makefile specific to the Tangent
277      linear and Adjoint Compiler (TAMC) that generates the adjoint code.
278      The latter is described in details in part V.
279      
280  \item \textit{utils}: this directory contains various utilities. The  \item \textit{utils}: this directory contains various utilities. The
281  subdirectory \textit{knudsen2} contains code and a makefile that compute    subdirectory \textit{knudsen2} contains code and a makefile that
282  coefficients of the polynomial approximation to the knudsen formula for an    compute coefficients of the polynomial approximation to the knudsen
283  ocean nonlinear equation of state. The \textit{matlab} subdirectory contains    formula for an ocean nonlinear equation of state. The
284  matlab scripts for reading model output directly into matlab. \textit{scripts%    \textit{matlab} subdirectory contains matlab scripts for reading
285  } contains C-shell post-processing scripts for joining processor-based and    model output directly into matlab. \textit{scripts} contains C-shell
286  tiled-based model output.    post-processing scripts for joining processor-based and tiled-based
287      model output.
288      
289    \item \textit{verification}: this directory contains the model
290      examples. See section \ref{sect:modelExamples}.
291    
 \item \textit{verification}: this directory contains the model examples. See  
 below.  
292  \end{itemize}  \end{itemize}
293    
294  \subsection{Model examples}  \section{Example experiments}
295    \label{sect:modelExamples}
296  Now that you have successfully downloaded the model code we recommend that  
297  you first try to run the examples provided with the base version. You will  %% a set of twenty-four pre-configured numerical experiments
298  probably want to run the example that is the closest to the configuration  
299  you will use eventually. The examples are located in subdirectories under  The MITgcm distribution comes with more than a dozen pre-configured
300  the directory \textit{verification} and are briefly described below (a full  numerical experiments. Some of these example experiments are tests of
301  description is given in section 2):  individual parts of the model code, but many are fully fledged
302    numerical simulations. A few of the examples are used for tutorial
303    documentation in sections \ref{sect:eg-baro} - \ref{sect:eg-global}.
304    The other examples follow the same general structure as the tutorial
305    examples. However, they only include brief instructions in a text file
306    called {\it README}.  The examples are located in subdirectories under
307    the directory \textit{verification}. Each example is briefly described
308    below.
309    
310  \subsubsection{List of model examples}  \subsection{Full list of model examples}
311    
312  \begin{itemize}  \begin{enumerate}
313      
314  \item \textit{exp0} - single layer, ocean double gyre (barotropic with  \item \textit{exp0} - single layer, ocean double gyre (barotropic with
315  free-surface).    free-surface). This experiment is described in detail in section
316      \ref{sect:eg-baro}.
 \item \textit{exp1} - 4 layers, ocean double gyre.  
317    
318    \item \textit{exp1} - Four layer, ocean double gyre. This experiment
319      is described in detail in section \ref{sect:eg-baroc}.
320      
321  \item \textit{exp2} - 4x4 degree global ocean simulation with steady  \item \textit{exp2} - 4x4 degree global ocean simulation with steady
322  climatological forcing.    climatological forcing. This experiment is described in detail in
323      section \ref{sect:eg-global}.
324  \item \textit{exp4} - flow over a Gaussian bump in open-water or channel    
325  with open boundaries.  \item \textit{exp4} - Flow over a Gaussian bump in open-water or
326      channel with open boundaries.
327  \item \textit{exp5} - inhomogenously forced ocean convection in a doubly    
328  periodic box.  \item \textit{exp5} - Inhomogenously forced ocean convection in a
329      doubly periodic box.
330    
331  \item \textit{front\_relax} - relaxation of an ocean thermal front (test for  \item \textit{front\_relax} - Relaxation of an ocean thermal front (test for
332  Gent/McWilliams scheme). 2D (Y-Z).  Gent/McWilliams scheme). 2D (Y-Z).
333    
334  \item \textit{internal wave} - ocean internal wave forced by open boundary  \item \textit{internal wave} - Ocean internal wave forced by open
335  conditions.    boundary conditions.
336      
337  \item \textit{natl\_box} - eastern subtropical North Atlantic with KPP  \item \textit{natl\_box} - Eastern subtropical North Atlantic with KPP
338  scheme; 1 month integration    scheme; 1 month integration
339      
340  \item \textit{hs94.1x64x5} - zonal averaged atmosphere using Held and Suarez  \item \textit{hs94.1x64x5} - Zonal averaged atmosphere using Held and
341  '94 forcing.    Suarez '94 forcing.
342      
343  \item \textit{hs94.128x64x5} - 3D atmosphere dynamics using Held and Suarez  \item \textit{hs94.128x64x5} - 3D atmosphere dynamics using Held and
344  '94 forcing.    Suarez '94 forcing.
345      
346  \item \textit{hs94.cs-32x32x5} - 3D atmosphere dynamics using Held and  \item \textit{hs94.cs-32x32x5} - 3D atmosphere dynamics using Held and
347  Suarez '94 forcing on the cubed sphere.    Suarez '94 forcing on the cubed sphere.
348      
349  \item \textit{aim.5l\_zon-ave} - Intermediate Atmospheric physics, 5 layers  \item \textit{aim.5l\_zon-ave} - Intermediate Atmospheric physics.
350  Molteni physics package. Global Zonal Mean configuration, 1x64x5 resolution.    Global Zonal Mean configuration, 1x64x5 resolution.
351      
352  \item \textit{aim.5l\_XZ\_Equatorial\_Slice} - Intermediate Atmospheric  \item \textit{aim.5l\_XZ\_Equatorial\_Slice} - Intermediate
353  physics, 5 layers Molteni physics package. Equatorial Slice configuration.    Atmospheric physics, equatorial Slice configuration.  2D (X-Z).
354  2D (X-Z).    
   
355  \item \textit{aim.5l\_Equatorial\_Channel} - Intermediate Atmospheric  \item \textit{aim.5l\_Equatorial\_Channel} - Intermediate Atmospheric
356  physics, 5 layers Molteni physics package. 3D Equatorial Channel    physics. 3D Equatorial Channel configuration.
357  configuration (not completely tested).    
358    \item \textit{aim.5l\_LatLon} - Intermediate Atmospheric physics.
359  \item \textit{aim.5l\_LatLon} - Intermediate Atmospheric physics, 5 layers    Global configuration, on latitude longitude grid with 128x64x5 grid
360  Molteni physics package. Global configuration, 128x64x5 resolution.    points ($2.8^\circ{\rm degree}$ resolution).
361      
362    \item \textit{adjustment.128x64x1} Barotropic adjustment problem on
363      latitude longitude grid with 128x64 grid points ($2.8^\circ{\rm
364        degree}$ resolution).
365      
366    \item \textit{adjustment.cs-32x32x1} Barotropic adjustment problem on
367      cube sphere grid with 32x32 points per face ( roughly $2.8^\circ{\rm
368        degree}$ resolution).
369      
370    \item \textit{advect\_cs} Two-dimensional passive advection test on
371      cube sphere grid.
372      
373    \item \textit{advect\_xy} Two-dimensional (horizontal plane) passive
374      advection test on Cartesian grid.
375      
376    \item \textit{advect\_yz} Two-dimensional (vertical plane) passive
377      advection test on Cartesian grid.
378      
379    \item \textit{carbon} Simple passive tracer experiment. Includes
380      derivative calculation. Described in detail in section
381      \ref{sect:eg-carbon-ad}.
382    
383    \item \textit{flt\_example} Example of using float package.
384      
385    \item \textit{global\_ocean.90x40x15} Global circulation with GM, flux
386      boundary conditions and poles.
387    
388    \item \textit{global\_ocean\_pressure} Global circulation in pressure
389      coordinate (non-Boussinesq ocean model). Described in detail in
390      section \ref{sect:eg-globalpressure}.
391      
392    \item \textit{solid-body.cs-32x32x1} Solid body rotation test for cube
393      sphere grid.
394    
395  \item \textit{adjustment.128x64x1}  \end{enumerate}
396    
397  \item \textit{adjustment.cs-32x32x1}  \subsection{Directory structure of model examples}
 \end{itemize}  
   
 \subsubsection{Directory structure of model examples}  
398    
399  Each example directory has the following subdirectories:  Each example directory has the following subdirectories:
400    
401  \begin{itemize}  \begin{itemize}
402  \item \textit{code}: contains the code particular to the example. At a  \item \textit{code}: contains the code particular to the example. At a
403  minimum, this directory includes the following files:    minimum, this directory includes the following files:
   
 \begin{itemize}  
 \item \textit{code/CPP\_EEOPTIONS.h}: declares CPP keys relative to the  
 ``execution environment'' part of the code. The default version is located  
 in \textit{eesupp/inc}.  
   
 \item \textit{code/CPP\_OPTIONS.h}: declares CPP keys relative to the  
 ``numerical model'' part of the code. The default version is located in  
 \textit{model/inc}.  
   
 \item \textit{code/SIZE.h}: declares size of underlying computational grid.  
 The default version is located in \textit{model/inc}.  
 \end{itemize}  
   
 In addition, other include files and subroutines might be present in \textit{%  
 code} depending on the particular experiment. See section 2 for more details.  
   
 \item \textit{input}: contains the input data files required to run the  
 example. At a mimimum, the \textit{input} directory contains the following  
 files:  
404    
405  \begin{itemize}    \begin{itemize}
406  \item \textit{input/data}: this file, written as a namelist, specifies the    \item \textit{code/CPP\_EEOPTIONS.h}: declares CPP keys relative to
407  main parameters for the experiment.      the ``execution environment'' part of the code. The default
408        version is located in \textit{eesupp/inc}.
409  \item \textit{input/data.pkg}: contains parameters relative to the packages    
410  used in the experiment.    \item \textit{code/CPP\_OPTIONS.h}: declares CPP keys relative to
411        the ``numerical model'' part of the code. The default version is
412        located in \textit{model/inc}.
413      
414      \item \textit{code/SIZE.h}: declares size of underlying
415        computational grid.  The default version is located in
416        \textit{model/inc}.
417      \end{itemize}
418      
419      In addition, other include files and subroutines might be present in
420      \textit{code} depending on the particular experiment. See Section 2
421      for more details.
422      
423    \item \textit{input}: contains the input data files required to run
424      the example. At a minimum, the \textit{input} directory contains the
425      following files:
426    
427      \begin{itemize}
428      \item \textit{input/data}: this file, written as a namelist,
429        specifies the main parameters for the experiment.
430      
431      \item \textit{input/data.pkg}: contains parameters relative to the
432        packages used in the experiment.
433      
434      \item \textit{input/eedata}: this file contains ``execution
435        environment'' data. At present, this consists of a specification
436        of the number of threads to use in $X$ and $Y$ under multithreaded
437        execution.
438      \end{itemize}
439      
440      In addition, you will also find in this directory the forcing and
441      topography files as well as the files describing the initial state
442      of the experiment.  This varies from experiment to experiment. See
443      section 2 for more details.
444    
445    \item \textit{results}: this directory contains the output file
446      \textit{output.txt} produced by the simulation example. This file is
447      useful for comparison with your own output when you run the
448      experiment.
449    \end{itemize}
450    
451    Once you have chosen the example you want to run, you are ready to
452    compile the code.
453    
454    \section{Building the code}
455    \label{sect:buildingCode}
456    
457    To compile the code, we use the {\em make} program. This uses a file
458    ({\em Makefile}) that allows us to pre-process source files, specify
459    compiler and optimization options and also figures out any file
460    dependencies. We supply a script ({\em genmake2}), described in
461    section \ref{sect:genmake}, that automatically creates the {\em
462      Makefile} for you. You then need to build the dependencies and
463    compile the code.
464    
465    As an example, let's assume that you want to build and run experiment
466    \textit{verification/exp2}. The are multiple ways and places to
467    actually do this but here let's build the code in
468    \textit{verification/exp2/input}:
469    \begin{verbatim}
470    % cd verification/exp2/input
471    \end{verbatim}
472    First, build the {\em Makefile}:
473    \begin{verbatim}
474    % ../../../tools/genmake2 -mods=../code
475    \end{verbatim}
476    The command line option tells {\em genmake} to override model source
477    code with any files in the directory {\em ./code/}.
478    
479  \item \textit{input/eedata}: this file contains ``execution environment''  On many systems, the {\em genmake2} program will be able to
480  data. At present, this consists of a specification of the number of threads  automatically recognize the hardware, find compilers and other tools
481  to use in $X$ and $Y$ under multithreaded execution.  within the user's path (``echo \$PATH''), and then choose an
482  \end{itemize}  appropriate set of options from the files contained in the {\em
483      tools/build\_options} directory.  Under some circumstances, a user
484    may have to create a new ``optfile'' in order to specify the exact
485    combination of compiler, compiler flags, libraries, and other options
486    necessary to build a particular configuration of MITgcm.  In such
487    cases, it is generally helpful to read the existing ``optfiles'' and
488    mimic their syntax.
489    
490    Through the MITgcm-support list, the MITgcm developers are willing to
491    provide help writing or modifing ``optfiles''.  And we encourage users
492    to post new ``optfiles'' (particularly ones for new machines or
493    architectures) to the
494    \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
495    MITgcm-support@mitgcm.org
496    \begin{rawhtml} </A> \end{rawhtml}
497    list.
498    
499  In addition, you will also find in this directory the forcing and topography  To specify an optfile to {\em genmake2}, the syntax is:
500  files as well as the files describing the initial state of the experiment.  \begin{verbatim}
501  This varies from experiment to experiment. See section 2 for more details.  % ../../../tools/genmake2 -mods=../code -of /path/to/optfile
502    \end{verbatim}
 \item \textit{results}: this directory contains the output file \textit{%  
 output.txt} produced by the simulation example. This file is useful for  
 comparison with your own output when you run the experiment.  
 \end{itemize}  
503    
504  Once you have chosen the example you want to run, you are ready to compile  Once a {\em Makefile} has been generated, we create the dependencies:
505  the code.  \begin{verbatim}
506    % make depend
507    \end{verbatim}
508    This modifies the {\em Makefile} by attaching a [long] list of files
509    upon which other files depend. The purpose of this is to reduce
510    re-compilation if and when you start to modify the code. The {\tt make
511      depend} command also creates links from the model source to this
512    directory.
513    
514  \subsection{Compiling the code}  Next compile the code:
515    \begin{verbatim}
516    % make
517    \end{verbatim}
518    The {\tt make} command creates an executable called \textit{mitgcmuv}.
519    Additional make ``targets'' are defined within the makefile to aid in
520    the production of adjoint and other versions of MITgcm.
521    
522  \subsubsection{The script \textit{genmake}}  Now you are ready to run the model. General instructions for doing so are
523    given in section \ref{sect:runModel}. Here, we can run the model with:
524    \begin{verbatim}
525    ./mitgcmuv > output.txt
526    \end{verbatim}
527    where we are re-directing the stream of text output to the file {\em
528    output.txt}.
529    
 To compile the code, use the script \textit{genmake} located in the \textit{%  
 tools} directory. \textit{genmake} is a script that generates the makefile.  
 It has been written so that the code can be compiled on a wide diversity of  
 machines and systems. However, if it doesn't work the first time on your  
 platform, you might need to edit certain lines of \textit{genmake} in the  
 section containing the setups for the different machines. The file is  
 structured like this:  
 \begin{verbatim}  
         .  
         .  
         .  
 general instructions (machine independent)  
         .  
         .  
         .  
     - setup machine 1  
     - setup machine 2  
     - setup machine 3  
     - setup machine 4  
        etc  
         .  
         .  
         .  
 \end{verbatim}  
   
 For example, the setup corresponding to a DEC alpha machine is reproduced  
 here:  
 \begin{verbatim}  
   case OSF1+mpi:  
     echo "Configuring for DEC Alpha"  
     set CPP        = ( '/usr/bin/cpp -P' )  
     set DEFINES    = ( ${DEFINES}  '-DTARGET_DEC -DWORDLENGTH=1' )  
     set KPP        = ( 'kapf' )  
     set KPPFILES   = ( 'main.F' )  
     set KFLAGS1    = ( '-scan=132 -noconc -cmp=' )  
     set FC         = ( 'f77' )  
     set FFLAGS     = ( '-convert big_endian -r8 -extend_source -automatic -call_shared -notransform_loops -align dcommons' )  
     set FOPTIM     = ( '-O5 -fast -tune host -inline all' )  
     set NOOPTFLAGS = ( '-O0' )  
     set LIBS       = ( '-lfmpi -lmpi -lkmp_osfp10 -pthread' )  
     set NOOPTFILES = ( 'barrier.F different_multiple.F external_fields_load.F')  
     set RMFILES    = ( '*.p.out' )  
     breaksw  
 \end{verbatim}  
   
 Typically, these are the lines that you might need to edit to make \textit{%  
 genmake} work on your platform if it doesn't work the first time. \textit{%  
 genmake} understands several options that are described here:  
530    
531  \begin{itemize}  \subsection{Building/compiling the code elsewhere}
 \item -rootdir=dir  
532    
533  indicates where the model root directory is relative to the directory where  In the example above (section \ref{sect:buildingCode}) we built the
534  you are compiling. This option is not needed if you compile in the \textit{%  executable in the {\em input} directory of the experiment for
535  bin} directory (which is the default compilation directory) or within the  convenience. You can also configure and compile the code in other
536  \textit{verification} tree.  locations, for example on a scratch disk with out having to copy the
537    entire source tree. The only requirement to do so is you have {\tt
538      genmake2} in your path or you know the absolute path to {\tt
539      genmake2}.
540    
541  \item -mods=dir1,dir2,...  The following sections outline some possible methods of organizing
542    your source and data.
543    
544  indicates the relative or absolute paths directories where the sources  \subsubsection{Building from the {\em ../code directory}}
 should take precedence over the default versions (located in \textit{model},  
 \textit{eesupp},...). Typically, this option is used when running the  
 examples, see below.  
545    
546  \item -enable=pkg1,pkg2,...  This is just as simple as building in the {\em input/} directory:
547    \begin{verbatim}
548    % cd verification/exp2/code
549    % ../../../tools/genmake2
550    % make depend
551    % make
552    \end{verbatim}
553    However, to run the model the executable ({\em mitgcmuv}) and input
554    files must be in the same place. If you only have one calculation to make:
555    \begin{verbatim}
556    % cd ../input
557    % cp ../code/mitgcmuv ./
558    % ./mitgcmuv > output.txt
559    \end{verbatim}
560    or if you will be making multiple runs with the same executable:
561    \begin{verbatim}
562    % cd ../
563    % cp -r input run1
564    % cp code/mitgcmuv run1
565    % cd run1
566    % ./mitgcmuv > output.txt
567    \end{verbatim}
568    
569  enables packages source code \textit{pkg1}, \textit{pkg2},... when creating  \subsubsection{Building from a new directory}
 the makefile.  
570    
571  \item -disable=pkg1,pkg2,...  Since the {\em input} directory contains input files it is often more
572    useful to keep {\em input} pristine and build in a new directory
573    within {\em verification/exp2/}:
574    \begin{verbatim}
575    % cd verification/exp2
576    % mkdir build
577    % cd build
578    % ../../../tools/genmake2 -mods=../code
579    % make depend
580    % make
581    \end{verbatim}
582    This builds the code exactly as before but this time you need to copy
583    either the executable or the input files or both in order to run the
584    model. For example,
585    \begin{verbatim}
586    % cp ../input/* ./
587    % ./mitgcmuv > output.txt
588    \end{verbatim}
589    or if you tend to make multiple runs with the same executable then
590    running in a new directory each time might be more appropriate:
591    \begin{verbatim}
592    % cd ../
593    % mkdir run1
594    % cp build/mitgcmuv run1/
595    % cp input/* run1/
596    % cd run1
597    % ./mitgcmuv > output.txt
598    \end{verbatim}
599    
600  disables packages source code \textit{pkg1}, \textit{pkg2},... when creating  \subsubsection{Building on a scratch disk}
 the makefile.  
601    
602  \item -platform=machine  Model object files and output data can use up large amounts of disk
603    space so it is often the case that you will be operating on a large
604    scratch disk. Assuming the model source is in {\em ~/MITgcm} then the
605    following commands will build the model in {\em /scratch/exp2-run1}:
606    \begin{verbatim}
607    % cd /scratch/exp2-run1
608    % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
609      -mods=~/MITgcm/verification/exp2/code
610    % make depend
611    % make
612    \end{verbatim}
613    To run the model here, you'll need the input files:
614    \begin{verbatim}
615    % cp ~/MITgcm/verification/exp2/input/* ./
616    % ./mitgcmuv > output.txt
617    \end{verbatim}
618    
619  specifies the platform for which you want the makefile. In general, you  As before, you could build in one directory and make multiple runs of
620  won't need this option. \textit{genmake} will select the right machine for  the one experiment:
621  you (the one you're working on!). However, this option is useful if you have  \begin{verbatim}
622  a choice of several compilers on one machine and you want to use the one  % cd /scratch/exp2
623  that is not the default (ex: \texttt{pgf77} instead of \texttt{f77} under  % mkdir build
624  Linux).  % cd build
625    % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
626      -mods=~/MITgcm/verification/exp2/code
627    % make depend
628    % make
629    % cd ../
630    % cp -r ~/MITgcm/verification/exp2/input run2
631    % cd run2
632    % ./mitgcmuv > output.txt
633    \end{verbatim}
634    
 \item -mpi  
635    
 this is used when you want to run the model in parallel processing mode  
 under mpi (see section on parallel computation for more details).  
636    
637  \item -jam  \subsection{Using \textit{genmake2}}
638    \label{sect:genmake}
639    
640  this is used when you want to run the model in parallel processing mode  To compile the code, first use the program \texttt{genmake2} (located
641  under jam (see section on parallel computation for more details).  in the \textit{tools} directory) to generate a Makefile.
642  \end{itemize}  \texttt{genmake2} is a shell script written to work with all
643    ``sh''--compatible shells including bash v1, bash v2, and Bourne.
644    Internally, \texttt{genmake2} determines the locations of needed
645    files, the compiler, compiler options, libraries, and Unix tools.  It
646    relies upon a number of ``optfiles'' located in the {\em
647      tools/build\_options} directory.
648    
649    The purpose of the optfiles is to provide all the compilation options
650    for particular ``platforms'' (where ``platform'' roughly means the
651    combination of the hardware and the compiler) and code configurations.
652    Given the combinations of possible compilers and library dependencies
653    ({\it eg.}  MPI and NetCDF) there may be numerous optfiles available
654    for a single machine.  The naming scheme for the majority of the
655    optfiles shipped with the code is
656    \begin{center}
657      {\bf OS\_HARDWARE\_COMPILER }
658    \end{center}
659    where
660    \begin{description}
661    \item[OS] is the name of the operating system (generally the
662      lower-case output of the {\tt 'uname'} command)
663    \item[HARDWARE] is a string that describes the CPU type and
664      corresponds to output from the  {\tt 'uname -m'} command:
665      \begin{description}
666      \item[ia32] is for ``x86'' machines such as i386, i486, i586, i686,
667        and athlon
668      \item[ia64] is for Intel IA64 systems (eg. Itanium, Itanium2)
669      \item[amd64] is AMD x86\_64 systems
670      \item[ppc] is for Mac PowerPC systems
671      \end{description}
672    \item[COMPILER] is the compiler name (generally, the name of the
673      FORTRAN executable)
674    \end{description}
675    
676    In many cases, the default optfiles are sufficient and will result in
677    usable Makefiles.  However, for some machines or code configurations,
678    new ``optfiles'' must be written. To create a new optfile, it is
679    generally best to start with one of the defaults and modify it to suit
680    your needs.  Like \texttt{genmake2}, the optfiles are all written
681    using a simple ``sh''--compatible syntax.  While nearly all variables
682    used within \texttt{genmake2} may be specified in the optfiles, the
683    critical ones that should be defined are:
684    
685    \begin{description}
686    \item[FC] the FORTRAN compiler (executable) to use
687    \item[DEFINES] the command-line DEFINE options passed to the compiler
688    \item[CPP] the C pre-processor to use
689    \item[NOOPTFLAGS] options flags for special files that should not be
690      optimized
691    \end{description}
692    
693  For some of the examples, there is a file called \textit{.genmakerc} in the  For example, the optfile for a typical Red Hat Linux machine (``ia32''
694  \textit{input} directory that has the relevant \textit{genmake} options for  architecture) using the GCC (g77) compiler is
 that particular example. In this way you don't need to type the options when  
 invoking \textit{genmake}.  
   
 \subsubsection{Compiling}  
   
 Let's assume that you want to run, say, example \textit{exp2} in the \textit{%  
 input} directory. To compile the code, type the following commands from the  
 model root tree:  
695  \begin{verbatim}  \begin{verbatim}
696  % cd verification/exp2/input  FC=g77
697  % ../../../tools/genmake  DEFINES='-D_BYTESWAPIO -DWORDLENGTH=4'
698  % make depend  CPP='cpp  -traditional -P'
699  % make  NOOPTFLAGS='-O0'
700    #  For IEEE, use the "-ffloat-store" option
701    if test "x$IEEE" = x ; then
702        FFLAGS='-Wimplicit -Wunused -Wuninitialized'
703        FOPTIM='-O3 -malign-double -funroll-loops'
704    else
705        FFLAGS='-Wimplicit -Wunused -ffloat-store'
706        FOPTIM='-O0 -malign-double'
707    fi
708  \end{verbatim}  \end{verbatim}
709    
710  If there is no \textit{.genmakerc} in the \textit{input} directory, you have  If you write an optfile for an unrepresented machine or compiler, you
711  to use the following options when invoking \textit{genmake}:  are strongly encouraged to submit the optfile to the MITgcm project
712    for inclusion.  Please send the file to the
713    \begin{rawhtml} <A href="mail-to:MITgcm-support@mitgcm.org"> \end{rawhtml}
714    \begin{center}
715      MITgcm-support@mitgcm.org
716    \end{center}
717    \begin{rawhtml} </A> \end{rawhtml}
718    mailing list.
719    
720    In addition to the optfiles, \texttt{genmake2} supports a number of
721    helpful command-line options.  A complete list of these options can be
722    obtained from:
723  \begin{verbatim}  \begin{verbatim}
724  % ../../../tools/genmake  -mods=../code  % genmake2 -h
725  \end{verbatim}  \end{verbatim}
726    
727  In addition, you will probably want to disable some of the packages. Taking  The most important command-line options are:
728  again the case of \textit{exp2}, the full \textit{genmake} command will  \begin{description}
729  probably look like this:    
730    \item[\texttt{--optfile=/PATH/FILENAME}] specifies the optfile that
731      should be used for a particular build.
732      
733      If no "optfile" is specified (either through the command line or the
734      MITGCM\_OPTFILE environment variable), genmake2 will try to make a
735      reasonable guess from the list provided in {\em
736        tools/build\_options}.  The method used for making this guess is
737      to first determine the combination of operating system and hardware
738      (eg. "linux\_ia32") and then find a working FORTRAN compiler within
739      the user's path.  When these three items have been identified,
740      genmake2 will try to find an optfile that has a matching name.
741      
742    \item[\texttt{--pdepend=/PATH/FILENAME}] specifies the dependency file
743      used for packages.
744      
745      If not specified, the default dependency file {\em pkg/pkg\_depend}
746      is used.  The syntax for this file is parsed on a line-by-line basis
747      where each line containes either a comment ("\#") or a simple
748      "PKGNAME1 (+|-)PKGNAME2" pairwise rule where the "+" or "-" symbol
749      specifies a "must be used with" or a "must not be used with"
750      relationship, respectively.  If no rule is specified, then it is
751      assumed that the two packages are compatible and will function
752      either with or without each other.
753      
754    \item[\texttt{--pdefault='PKG1 PKG2 PKG3 ...'}] specifies the default
755      set of packages to be used.
756      
757      If not set, the default package list will be read from {\em
758        pkg/pkg\_default}
759      
760    \item[\texttt{--adof=/path/to/file}] specifies the "adjoint" or
761      automatic differentiation options file to be used.  The file is
762      analogous to the ``optfile'' defined above but it specifies
763      information for the AD build process.
764      
765      The default file is located in {\em
766        tools/adjoint\_options/adjoint\_default} and it defines the "TAF"
767      and "TAMC" compilers.  An alternate version is also available at
768      {\em tools/adjoint\_options/adjoint\_staf} that selects the newer
769      "STAF" compiler.  As with any compilers, it is helpful to have their
770      directories listed in your {\tt \$PATH} environment variable.
771      
772    \item[\texttt{--mods='DIR1 DIR2 DIR3 ...'}] specifies a list of
773      directories containing ``modifications''.  These directories contain
774      files with names that may (or may not) exist in the main MITgcm
775      source tree but will be overridden by any identically-named sources
776      within the ``MODS'' directories.
777      
778      The order of precedence for this "name-hiding" is as follows:
779      \begin{itemize}
780      \item ``MODS'' directories (in the order given)
781      \item Packages either explicitly specified or provided by default
782        (in the order given)
783      \item Packages included due to package dependencies (in the order
784        that that package dependencies are parsed)
785      \item The "standard dirs" (which may have been specified by the
786        ``-standarddirs'' option)
787      \end{itemize}
788      
789    \item[\texttt{--make=/path/to/gmake}] Due to the poor handling of
790      soft-links and other bugs common with the \texttt{make} versions
791      provided by commercial Unix vendors, GNU \texttt{make} (sometimes
792      called \texttt{gmake}) should be preferred.  This option provides a
793      means for specifying the make executable to be used.
794    
795    \end{description}
796    
797    
798    
799    \section{Running the model}
800    \label{sect:runModel}
801    
802    If compilation finished succesfuully (section \ref{sect:buildModel})
803    then an executable called {\em mitgcmuv} will now exist in the local
804    directory.
805    
806    To run the model as a single process (ie. not in parallel) simply
807    type:
808  \begin{verbatim}  \begin{verbatim}
809  % ../../../tools/genmake  -mods=../code  -disable=kpp,gmredi,aim,...  % ./mitgcmuv
810  \end{verbatim}  \end{verbatim}
811    The ``./'' is a safe-guard to make sure you use the local executable
812  The make command creates an executable called \textit{mitgcmuv}.  in case you have others that exist in your path (surely odd if you
813    do!). The above command will spew out many lines of text output to
814  Note that you can compile and run the code in another directory than \textit{%  your screen.  This output contains details such as parameter values as
815  input}. You just need to make sure that you copy the input data files into  well as diagnostics such as mean Kinetic energy, largest CFL number,
816  the directory where you want to run the model. For example to compile from  etc. It is worth keeping this text output with the binary output so we
817  \textit{code}:  normally re-direct the {\em stdout} stream as follows:
818  \begin{verbatim}  \begin{verbatim}
819  % cd verification/exp2/code  % ./mitgcmuv > output.txt
 % ../../../tools/genmake  
 % make depend  
 % make  
820  \end{verbatim}  \end{verbatim}
821    
822  \subsection{Running the model}  For the example experiments in {\em verification}, an example of the
823    output is kept in {\em results/output.txt} for comparison. You can compare
824    your {\em output.txt} with this one to check that the set-up works.
825    
826    
 The first thing to do is to run the code by typing \textit{mitgcmuv} and see  
 what happens. You can compare what you get with what is in the \textit{%  
 results} directory. Unless noted otherwise, most examples are set up to run  
 for a few time steps only so that you can quickly figure out whether the  
 model is working or not.  
827    
828  \subsubsection{Output files}  \subsection{Output files}
829    
830  The model produces various output files. At a minimum, the instantaneous  The model produces various output files. At a minimum, the instantaneous
831  ``state'' of the model is written out, which is made of the following files:  ``state'' of the model is written out, which is made of the following files:
# Line 445  as the pickup files but are named differ Line 876  as the pickup files but are named differ
876  used to restart the model but are overwritten every other time they are  used to restart the model but are overwritten every other time they are
877  output to save disk space during long integrations.  output to save disk space during long integrations.
878    
879  \subsubsection{Looking at the output}  \subsection{Looking at the output}
880    
881  All the model data are written according to a ``meta/data'' file format.  All the model data are written according to a ``meta/data'' file format.
882  Each variable is associated with two files with suffix names \textit{.data}  Each variable is associated with two files with suffix names \textit{.data}
# Line 459  written in this format. The matlab scrip Line 890  written in this format. The matlab scrip
890  \textit{utils/matlab} under the root tree. The script \textit{rdmds.m} reads  \textit{utils/matlab} under the root tree. The script \textit{rdmds.m} reads
891  the data. Look at the comments inside the script to see how to use it.  the data. Look at the comments inside the script to see how to use it.
892    
893  \section{Code structure}  Some examples of reading and visualizing some output in {\em Matlab}:
894    \begin{verbatim}
895    % matlab
896    >> H=rdmds('Depth');
897    >> contourf(H');colorbar;
898    >> title('Depth of fluid as used by model');
899    
900    >> eta=rdmds('Eta',10);
901    >> imagesc(eta');axis ij;colorbar;
902    >> title('Surface height at iter=10');
903    
904  \section{Doing it yourself: customizing the code}  >> eta=rdmds('Eta',[0:10:100]);
905    >> for n=1:11; imagesc(eta(:,:,n)');axis ij;colorbar;pause(.5);end
906    \end{verbatim}
907    
908  \subsection{\protect\bigskip Configuration and setup}  \section{Doing it yourself: customizing the code}
909    
910  When you are ready to run the model in the configuration you want, the  When you are ready to run the model in the configuration you want, the
911  easiest thing is to use and adapt the setup of the case studies experiment  easiest thing is to use and adapt the setup of the case studies
912  (described previously) that is the closest to your configuration. Then, the  experiment (described previously) that is the closest to your
913  amount of setup will be minimized. In this section, we focus on the setup  configuration. Then, the amount of setup will be minimized. In this
914  relative to the ''numerical model'' part of the code (the setup relative to  section, we focus on the setup relative to the ``numerical model''
915  the ''execution environment'' part is covered in the parallel implementation  part of the code (the setup relative to the ``execution environment''
916  section) and on the variables and parameters that you are likely to change.  part is covered in the parallel implementation section) and on the
917    variables and parameters that you are likely to change.
918  The CPP keys relative to the ''numerical model'' part of the code are all  
919  defined and set in the file \textit{CPP\_OPTIONS.h }in the directory \textit{%  \subsection{Configuration and setup}
920  model/inc }or in one of the \textit{code }directories of the case study  
921  experiments under \textit{verification.} The model parameters are defined  The CPP keys relative to the ``numerical model'' part of the code are
922  and declared in the file \textit{model/inc/PARAMS.h }and their default  all defined and set in the file \textit{CPP\_OPTIONS.h }in the
923  values are set in the routine \textit{model/src/set\_defaults.F. }The  directory \textit{ model/inc }or in one of the \textit{code
924  default values can be modified in the namelist file \textit{data }which  }directories of the case study experiments under
925  needs to be located in the directory where you will run the model. The  \textit{verification.} The model parameters are defined and declared
926  parameters are initialized in the routine \textit{model/src/ini\_parms.F}.  in the file \textit{model/inc/PARAMS.h }and their default values are
927  Look at this routine to see in what part of the namelist the parameters are  set in the routine \textit{model/src/set\_defaults.F. }The default
928  located.  values can be modified in the namelist file \textit{data }which needs
929    to be located in the directory where you will run the model. The
930  In what follows the parameters are grouped into categories related to the  parameters are initialized in the routine
931  computational domain, the equations solved in the model, and the simulation  \textit{model/src/ini\_parms.F}.  Look at this routine to see in what
932  controls.  part of the namelist the parameters are located.
933    
934  \subsubsection{Computational domain, geometry and time-discretization}  In what follows the parameters are grouped into categories related to
935    the computational domain, the equations solved in the model, and the
936  \begin{itemize}  simulation controls.
937  \item dimensions  
938  \end{itemize}  \subsection{Computational domain, geometry and time-discretization}
939    
940  The number of points in the x, y,\textit{\ }and r\textit{\ }directions are  \begin{description}
941  represented by the variables \textbf{sNx}\textit{, }\textbf{sNy}\textit{, }%  \item[dimensions] \
942  and \textbf{Nr}\textit{\ }respectively which are declared and set in the    
943  file \textit{model/inc/SIZE.h. }(Again, this assumes a mono-processor    The number of points in the x, y, and r directions are represented
944  calculation. For multiprocessor calculations see section on parallel    by the variables \textbf{sNx}, \textbf{sNy} and \textbf{Nr}
945  implementation.)    respectively which are declared and set in the file
946      \textit{model/inc/SIZE.h}.  (Again, this assumes a mono-processor
947  \begin{itemize}    calculation. For multiprocessor calculations see the section on
948  \item grid    parallel implementation.)
949  \end{itemize}  
950    \item[grid] \
951  Three different grids are available: cartesian, spherical polar, and    
952  curvilinear (including the cubed sphere). The grid is set through the    Three different grids are available: cartesian, spherical polar, and
953  logical variables \textbf{usingCartesianGrid}\textit{, }\textbf{%    curvilinear (which includes the cubed sphere). The grid is set
954  usingSphericalPolarGrid}\textit{, }and \textit{\ }\textbf{%    through the logical variables \textbf{usingCartesianGrid},
955  usingCurvilinearGrid}\textit{. }In the case of spherical and curvilinear    \textbf{usingSphericalPolarGrid}, and \textbf{usingCurvilinearGrid}.
956  grids, the southern boundary is defined through the variable \textbf{phiMin}%    In the case of spherical and curvilinear grids, the southern
957  \textit{\ }which corresponds to the latitude of the southern most cell face    boundary is defined through the variable \textbf{phiMin} which
958  (in degrees). The resolution along the x and y directions is controlled by    corresponds to the latitude of the southern most cell face (in
959  the 1D arrays \textbf{delx}\textit{\ }and \textbf{dely}\textit{\ }(in meters    degrees). The resolution along the x and y directions is controlled
960  in the case of a cartesian grid, in degrees otherwise). The vertical grid    by the 1D arrays \textbf{delx} and \textbf{dely} (in meters in the
961  spacing is set through the 1D array \textbf{delz }for the ocean (in meters)    case of a cartesian grid, in degrees otherwise).  The vertical grid
962  or \textbf{delp}\textit{\ }for the atmosphere (in Pa). The variable \textbf{%    spacing is set through the 1D array \textbf{delz} for the ocean (in
963  Ro\_SeaLevel} represents the standard position of Sea-Level in ''R''    meters) or \textbf{delp} for the atmosphere (in Pa).  The variable
964  coordinate. This is typically set to 0m for the ocean (default value) and 10$%    \textbf{Ro\_SeaLevel} represents the standard position of Sea-Level
965  ^{5}$Pa for the atmosphere. For the atmosphere, also set the logical    in ``R'' coordinate. This is typically set to 0m for the ocean
966  variable \textbf{groundAtK1} to '.\texttt{TRUE}.'. which put the first level    (default value) and 10$^{5}$Pa for the atmosphere. For the
967  (k=1) at the lower boundary (ground).    atmosphere, also set the logical variable \textbf{groundAtK1} to
968      \texttt{'.TRUE.'} which puts the first level (k=1) at the lower
969  For the cartesian grid case, the Coriolis parameter $f$ is set through the    boundary (ground).
970  variables \textbf{f0}\textit{\ }and \textbf{beta}\textit{\ }which correspond    
971  to the reference Coriolis parameter (in s$^{-1}$) and $\frac{\partial f}{%    For the cartesian grid case, the Coriolis parameter $f$ is set
972  \partial y}$(in m$^{-1}$s$^{-1}$) respectively. If \textbf{beta }\textit{\ }%    through the variables \textbf{f0} and \textbf{beta} which correspond
973  is set to a nonzero value, \textbf{f0}\textit{\ }is the value of $f$ at the    to the reference Coriolis parameter (in s$^{-1}$) and
974  southern edge of the domain.    $\frac{\partial f}{ \partial y}$(in m$^{-1}$s$^{-1}$) respectively.
975      If \textbf{beta } is set to a nonzero value, \textbf{f0} is the
976  \begin{itemize}    value of $f$ at the southern edge of the domain.
977  \item topography - full and partial cells  
978  \end{itemize}  \item[topography - full and partial cells] \
979      
980  The domain bathymetry is read from a file that contains a 2D (x,y) map of    The domain bathymetry is read from a file that contains a 2D (x,y)
981  depths (in m) for the ocean or pressures (in Pa) for the atmosphere. The    map of depths (in m) for the ocean or pressures (in Pa) for the
982  file name is represented by the variable \textbf{bathyFile}\textit{. }The    atmosphere. The file name is represented by the variable
983  file is assumed to contain binary numbers giving the depth (pressure) of the    \textbf{bathyFile}. The file is assumed to contain binary numbers
984  model at each grid cell, ordered with the x coordinate varying fastest. The    giving the depth (pressure) of the model at each grid cell, ordered
985  points are ordered from low coordinate to high coordinate for both axes. The    with the x coordinate varying fastest. The points are ordered from
986  model code applies without modification to enclosed, periodic, and double    low coordinate to high coordinate for both axes. The model code
987  periodic domains. Periodicity is assumed by default and is suppressed by    applies without modification to enclosed, periodic, and double
988  setting the depths to 0m for the cells at the limits of the computational    periodic domains. Periodicity is assumed by default and is
989  domain (note: not sure this is the case for the atmosphere). The precision    suppressed by setting the depths to 0m for the cells at the limits
990  with which to read the binary data is controlled by the integer variable    of the computational domain (note: not sure this is the case for the
991  \textbf{readBinaryPrec }which can take the value \texttt{32} (single    atmosphere). The precision with which to read the binary data is
992  precision) or \texttt{64} (double precision). See the matlab program \textit{%    controlled by the integer variable \textbf{readBinaryPrec} which can
993  gendata.m }in the \textit{input }directories under \textit{verification }to    take the value \texttt{32} (single precision) or \texttt{64} (double
994  see how the bathymetry files are generated for the case study experiments.    precision). See the matlab program \textit{gendata.m} in the
995      \textit{input} directories under \textit{verification} to see how
996  To use the partial cell capability, the variable \textbf{hFacMin}\textit{\ }%    the bathymetry files are generated for the case study experiments.
997  needs to be set to a value between 0 and 1 (it is set to 1 by default)    
998  corresponding to the minimum fractional size of the cell. For example if the    To use the partial cell capability, the variable \textbf{hFacMin}
999  bottom cell is 500m thick and \textbf{hFacMin}\textit{\ }is set to 0.1, the    needs to be set to a value between 0 and 1 (it is set to 1 by
1000  actual thickness of the cell (i.e. used in the code) can cover a range of    default) corresponding to the minimum fractional size of the cell.
1001  discrete values 50m apart from 50m to 500m depending on the value of the    For example if the bottom cell is 500m thick and \textbf{hFacMin} is
1002  bottom depth (in \textbf{bathyFile}) at this point.    set to 0.1, the actual thickness of the cell (i.e. used in the code)
1003      can cover a range of discrete values 50m apart from 50m to 500m
1004  Note that the bottom depths (or pressures) need not coincide with the models    depending on the value of the bottom depth (in \textbf{bathyFile})
1005  levels as deduced from \textbf{delz}\textit{\ }or\textit{\ }\textbf{delp}%    at this point.
1006  \textit{. }The model will interpolate the numbers in \textbf{bathyFile}%    
1007  \textit{\ }so that they match the levels obtained from \textbf{delz}\textit{%    Note that the bottom depths (or pressures) need not coincide with
1008  \ }or\textit{\ }\textbf{delp}\textit{\ }and \textbf{hFacMin}\textit{. }    the models levels as deduced from \textbf{delz} or \textbf{delp}.
1009      The model will interpolate the numbers in \textbf{bathyFile} so that
1010  (Note: the atmospheric case is a bit more complicated than what is written    they match the levels obtained from \textbf{delz} or \textbf{delp}
1011  here I think. To come soon...)    and \textbf{hFacMin}.
1012      
1013  \begin{itemize}    (Note: the atmospheric case is a bit more complicated than what is
1014  \item time-discretization    written here I think. To come soon...)
1015  \end{itemize}  
1016    \item[time-discretization] \
1017  The time steps are set through the real variables \textbf{deltaTMom }and    
1018  \textbf{deltaTtracer }(in s) which represent the time step for the momentum    The time steps are set through the real variables \textbf{deltaTMom}
1019  and tracer equations, respectively. For synchronous integrations, simply set    and \textbf{deltaTtracer} (in s) which represent the time step for
1020  the two variables to the same value (or you can prescribe one time step only    the momentum and tracer equations, respectively. For synchronous
1021  through the variable \textbf{deltaT}). The Adams-Bashforth stabilizing    integrations, simply set the two variables to the same value (or you
1022  parameter is set through the variable \textbf{abEps }(dimensionless). The    can prescribe one time step only through the variable
1023  stagger baroclinic time stepping can be activated by setting the logical    \textbf{deltaT}). The Adams-Bashforth stabilizing parameter is set
1024  variable \textbf{staggerTimeStep }to '.\texttt{TRUE}.'.    through the variable \textbf{abEps} (dimensionless). The stagger
1025      baroclinic time stepping can be activated by setting the logical
1026  \subsubsection{Equation of state}    variable \textbf{staggerTimeStep} to \texttt{'.TRUE.'}.
1027    
1028  First, because the model equations are written in terms of perturbations, a  \end{description}
1029  reference thermodynamic state needs to be specified. This is done through  
1030  the 1D arrays \textbf{tRef}\textit{\ }and \textbf{sRef}. \textbf{tRef }%  
1031  specifies the reference potential temperature profile (in $^{o}$C for  \subsection{Equation of state}
1032  the ocean and $^{o}$K for the atmosphere) starting from the level  
1033  k=1. Similarly, \textbf{sRef}\textit{\ }specifies the reference salinity  First, because the model equations are written in terms of
1034  profile (in ppt) for the ocean or the reference specific humidity profile  perturbations, a reference thermodynamic state needs to be specified.
1035  (in g/kg) for the atmosphere.  This is done through the 1D arrays \textbf{tRef} and \textbf{sRef}.
1036    \textbf{tRef} specifies the reference potential temperature profile
1037  The form of the equation of state is controlled by the character variables  (in $^{o}$C for the ocean and $^{o}$K for the atmosphere) starting
1038  \textbf{buoyancyRelation}\textit{\ }and \textbf{eosType}\textit{. }\textbf{%  from the level k=1. Similarly, \textbf{sRef} specifies the reference
1039  buoyancyRelation}\textit{\ }is set to '\texttt{OCEANIC}' by default and  salinity profile (in ppt) for the ocean or the reference specific
1040  needs to be set to '\texttt{ATMOSPHERIC}' for atmosphere simulations. In  humidity profile (in g/kg) for the atmosphere.
1041  this case, \textbf{eosType}\textit{\ }must be set to '\texttt{IDEALGAS}'.  
1042  For the ocean, two forms of the equation of state are available: linear (set  The form of the equation of state is controlled by the character
1043  \textbf{eosType}\textit{\ }to '\texttt{LINEAR}') and a polynomial  variables \textbf{buoyancyRelation} and \textbf{eosType}.
1044  approximation to the full nonlinear equation ( set \textbf{eosType}\textit{\  \textbf{buoyancyRelation} is set to \texttt{'OCEANIC'} by default and
1045  }to '\texttt{POLYNOMIAL}'). In the linear case, you need to specify the  needs to be set to \texttt{'ATMOSPHERIC'} for atmosphere simulations.
1046  thermal and haline expansion coefficients represented by the variables  In this case, \textbf{eosType} must be set to \texttt{'IDEALGAS'}.
1047  \textbf{tAlpha}\textit{\ }(in K$^{-1}$) and \textbf{sBeta}\textit{\ }(in ppt$%  For the ocean, two forms of the equation of state are available:
1048  ^{-1}$). For the nonlinear case, you need to generate a file of polynomial  linear (set \textbf{eosType} to \texttt{'LINEAR'}) and a polynomial
1049  coefficients called \textit{POLY3.COEFFS. }To do this, use the program  approximation to the full nonlinear equation ( set \textbf{eosType} to
1050  \textit{utils/knudsen2/knudsen2.f }under the model tree (a Makefile is  \texttt{'POLYNOMIAL'}). In the linear case, you need to specify the
1051  available in the same directory and you will need to edit the number and the  thermal and haline expansion coefficients represented by the variables
1052  values of the vertical levels in \textit{knudsen2.f }so that they match  \textbf{tAlpha} (in K$^{-1}$) and \textbf{sBeta} (in ppt$^{-1}$). For
1053  those of your configuration). \textit{\ }  the nonlinear case, you need to generate a file of polynomial
1054    coefficients called \textit{POLY3.COEFFS}. To do this, use the program
1055  \subsubsection{Momentum equations}  \textit{utils/knudsen2/knudsen2.f} under the model tree (a Makefile is
1056    available in the same directory and you will need to edit the number
1057  In this section, we only focus for now on the parameters that you are likely  and the values of the vertical levels in \textit{knudsen2.f} so that
1058  to change, i.e. the ones relative to forcing and dissipation for example.  they match those of your configuration).
1059  The details relevant to the vector-invariant form of the equations and the  
1060  various advection schemes are not covered for the moment. We assume that you  There there are also higher polynomials for the equation of state:
1061  use the standard form of the momentum equations (i.e. the flux-form) with  \begin{description}
1062  the default advection scheme. Also, there are a few logical variables that  \item[\texttt{'UNESCO'}:] The UNESCO equation of state formula of
1063  allow you to turn on/off various terms in the momentum equation. These    Fofonoff and Millard \cite{fofonoff83}. This equation of state
1064  variables are called \textbf{momViscosity, momAdvection, momForcing,    assumes in-situ temperature, which is not a model variable; {\em its
1065  useCoriolis, momPressureForcing, momStepping}\textit{, }and \textit{\ }%      use is therefore discouraged, and it is only listed for
1066  \textbf{metricTerms }and are assumed to be set to '.\texttt{TRUE}.' here.      completeness}.
1067  Look at the file \textit{model/inc/PARAMS.h }for a precise definition of  \item[\texttt{'JMD95Z'}:] A modified UNESCO formula by Jackett and
1068  these variables.    McDougall \cite{jackett95}, which uses the model variable potential
1069      temperature as input. The \texttt{'Z'} indicates that this equation
1070  \begin{itemize}    of state uses a horizontally and temporally constant pressure
1071  \item initialization    $p_{0}=-g\rho_{0}z$.
1072  \end{itemize}  \item[\texttt{'JMD95P'}:] A modified UNESCO formula by Jackett and
1073      McDougall \cite{jackett95}, which uses the model variable potential
1074  The velocity components are initialized to 0 unless the simulation is    temperature as input. The \texttt{'P'} indicates that this equation
1075  starting from a pickup file (see section on simulation control parameters).    of state uses the actual hydrostatic pressure of the last time
1076      step. Lagging the pressure in this way requires an additional pickup
1077  \begin{itemize}    file for restarts.
1078  \item forcing  \item[\texttt{'MDJWF'}:] The new, more accurate and less expensive
1079  \end{itemize}    equation of state by McDougall et~al. \cite{mcdougall03}. It also
1080      requires lagging the pressure and therefore an additional pickup
1081  This section only applies to the ocean. You need to generate wind-stress    file for restarts.
1082  data into two files \textbf{zonalWindFile}\textit{\ }and \textbf{%  \end{description}
1083  meridWindFile }corresponding to the zonal and meridional components of the  For none of these options an reference profile of temperature or
1084  wind stress, respectively (if you want the stress to be along the direction  salinity is required.
1085  of only one of the model horizontal axes, you only need to generate one  
1086  file). The format of the files is similar to the bathymetry file. The zonal  \subsection{Momentum equations}
1087  (meridional) stress data are assumed to be in Pa and located at U-points  
1088  (V-points). As for the bathymetry, the precision with which to read the  In this section, we only focus for now on the parameters that you are
1089  binary data is controlled by the variable \textbf{readBinaryPrec}.\textbf{\ }  likely to change, i.e. the ones relative to forcing and dissipation
1090  See the matlab program \textit{gendata.m }in the \textit{input }directories  for example.  The details relevant to the vector-invariant form of the
1091  under \textit{verification }to see how simple analytical wind forcing data  equations and the various advection schemes are not covered for the
1092  are generated for the case study experiments.  moment. We assume that you use the standard form of the momentum
1093    equations (i.e. the flux-form) with the default advection scheme.
1094  There is also the possibility of prescribing time-dependent periodic  Also, there are a few logical variables that allow you to turn on/off
1095  forcing. To do this, concatenate the successive time records into a single  various terms in the momentum equation. These variables are called
1096  file (for each stress component) ordered in a (x, y, t) fashion and set the  \textbf{momViscosity, momAdvection, momForcing, useCoriolis,
1097  following variables: \textbf{periodicExternalForcing }to '.\texttt{TRUE}.',    momPressureForcing, momStepping} and \textbf{metricTerms }and are
1098  \textbf{externForcingPeriod }to the period (in s) of which the forcing  assumed to be set to \texttt{'.TRUE.'} here.  Look at the file
1099  varies (typically 1 month), and \textbf{externForcingCycle }to the repeat  \textit{model/inc/PARAMS.h }for a precise definition of these
1100  time (in s) of the forcing (typically 1 year -- note: \textbf{%  variables.
1101  externForcingCycle }must be a multiple of \textbf{externForcingPeriod}).  
1102  With these variables set up, the model will interpolate the forcing linearly  \begin{description}
1103  at each iteration.  \item[initialization] \
1104      
1105  \begin{itemize}    The velocity components are initialized to 0 unless the simulation
1106  \item dissipation    is starting from a pickup file (see section on simulation control
1107  \end{itemize}    parameters).
1108    
1109  The lateral eddy viscosity coefficient is specified through the variable  \item[forcing] \
1110  \textbf{viscAh}\textit{\ }(in m$^{2}$s$^{-1}$). The vertical eddy viscosity    
1111  coefficient is specified through the variable \textbf{viscAz }(in m$^{2}$s$%    This section only applies to the ocean. You need to generate
1112  ^{-1}$) for the ocean and \textbf{viscAp}\textit{\ }(in Pa$^{2}$s$^{-1}$)    wind-stress data into two files \textbf{zonalWindFile} and
1113  for the atmosphere. The vertical diffusive fluxes can be computed implicitly    \textbf{meridWindFile} corresponding to the zonal and meridional
1114  by setting the logical variable \textbf{implicitViscosity }to '.\texttt{TRUE}%    components of the wind stress, respectively (if you want the stress
1115  .'. In addition, biharmonic mixing can be added as well through the variable    to be along the direction of only one of the model horizontal axes,
1116  \textbf{viscA4}\textit{\ }(in m$^{4}$s$^{-1}$). On a spherical polar grid,    you only need to generate one file). The format of the files is
1117  you might also need to set the variable \textbf{cosPower} which is set to 0    similar to the bathymetry file. The zonal (meridional) stress data
1118  by default and which represents the power of cosine of latitude to multiply    are assumed to be in Pa and located at U-points (V-points). As for
1119  viscosity. Slip or no-slip conditions at lateral and bottom boundaries are    the bathymetry, the precision with which to read the binary data is
1120  specified through the logical variables \textbf{no\_slip\_sides}\textit{\ }%    controlled by the variable \textbf{readBinaryPrec}.  See the matlab
1121  and \textbf{no\_slip\_bottom}. If set to '\texttt{.FALSE.}', free-slip    program \textit{gendata.m} in the \textit{input} directories under
1122  boundary conditions are applied. If no-slip boundary conditions are applied    \textit{verification} to see how simple analytical wind forcing data
1123  at the bottom, a bottom drag can be applied as well. Two forms are    are generated for the case study experiments.
1124  available: linear (set the variable \textbf{bottomDragLinear}\textit{\ }in s$%    
1125  ^{-1}$) and quadratic (set the variable \textbf{bottomDragQuadratic}\textit{%    There is also the possibility of prescribing time-dependent periodic
1126  \ }in m$^{-1}$).    forcing. To do this, concatenate the successive time records into a
1127      single file (for each stress component) ordered in a (x,y,t) fashion
1128  The Fourier and Shapiro filters are described elsewhere.    and set the following variables: \textbf{periodicExternalForcing }to
1129      \texttt{'.TRUE.'}, \textbf{externForcingPeriod }to the period (in s)
1130  \begin{itemize}    of which the forcing varies (typically 1 month), and
1131  \item C-D scheme    \textbf{externForcingCycle} to the repeat time (in s) of the forcing
1132  \end{itemize}    (typically 1 year -- note: \textbf{ externForcingCycle} must be a
1133      multiple of \textbf{externForcingPeriod}).  With these variables set
1134  If you run at a sufficiently coarse resolution, you will need the C-D scheme    up, the model will interpolate the forcing linearly at each
1135  for the computation of the Coriolis terms. The variable\textbf{\ tauCD},    iteration.
1136  which represents the C-D scheme coupling timescale (in s) needs to be set.  
1137    \item[dissipation] \
1138  \begin{itemize}    
1139  \item calculation of pressure/geopotential    The lateral eddy viscosity coefficient is specified through the
1140  \end{itemize}    variable \textbf{viscAh} (in m$^{2}$s$^{-1}$). The vertical eddy
1141      viscosity coefficient is specified through the variable
1142  First, to run a non-hydrostatic ocean simulation, set the logical variable    \textbf{viscAz} (in m$^{2}$s$^{-1}$) for the ocean and
1143  \textbf{nonHydrostatic} to '.\texttt{TRUE}.'. The pressure field is then    \textbf{viscAp} (in Pa$^{2}$s$^{-1}$) for the atmosphere.  The
1144  inverted through a 3D elliptic equation. (Note: this capability is not    vertical diffusive fluxes can be computed implicitly by setting the
1145  available for the atmosphere yet.) By default, a hydrostatic simulation is    logical variable \textbf{implicitViscosity }to \texttt{'.TRUE.'}.
1146  assumed and a 2D elliptic equation is used to invert the pressure field. The    In addition, biharmonic mixing can be added as well through the
1147  parameters controlling the behaviour of the elliptic solvers are the    variable \textbf{viscA4} (in m$^{4}$s$^{-1}$). On a spherical polar
1148  variables \textbf{cg2dMaxIters}\textit{\ }and \textbf{cg2dTargetResidual }%    grid, you might also need to set the variable \textbf{cosPower}
1149  for the 2D case and \textbf{cg3dMaxIters}\textit{\ }and \textbf{%    which is set to 0 by default and which represents the power of
1150  cg3dTargetResidual }for the 3D case. You probably won't need to alter the    cosine of latitude to multiply viscosity. Slip or no-slip conditions
1151  default values (are we sure of this?).    at lateral and bottom boundaries are specified through the logical
1152      variables \textbf{no\_slip\_sides} and \textbf{no\_slip\_bottom}. If
1153  For the calculation of the surface pressure (for the ocean) or surface    set to \texttt{'.FALSE.'}, free-slip boundary conditions are
1154  geopotential (for the atmosphere) you need to set the logical variables    applied. If no-slip boundary conditions are applied at the bottom, a
1155  \textbf{rigidLid} and \textbf{implicitFreeSurface}\textit{\ }(set one to '.%    bottom drag can be applied as well. Two forms are available: linear
1156  \texttt{TRUE}.' and the other to '.\texttt{FALSE}.' depending on how you    (set the variable \textbf{bottomDragLinear} in s$ ^{-1}$) and
1157  want to deal with the ocean upper or atmosphere lower boundary).    quadratic (set the variable \textbf{bottomDragQuadratic} in
1158      m$^{-1}$).
1159  \subsubsection{Tracer equations}  
1160      The Fourier and Shapiro filters are described elsewhere.
1161  This section covers the tracer equations i.e. the potential temperature  
1162  equation and the salinity (for the ocean) or specific humidity (for the  \item[C-D scheme] \
1163  atmosphere) equation. As for the momentum equations, we only describe for    
1164  now the parameters that you are likely to change. The logical variables    If you run at a sufficiently coarse resolution, you will need the
1165  \textbf{tempDiffusion}\textit{, }\textbf{tempAdvection}\textit{, }\textbf{%    C-D scheme for the computation of the Coriolis terms. The
1166  tempForcing}\textit{,} and \textbf{tempStepping} allow you to turn on/off    variable\textbf{\ tauCD}, which represents the C-D scheme coupling
1167  terms in the temperature equation (same thing for salinity or specific    timescale (in s) needs to be set.
1168  humidity with variables \textbf{saltDiffusion}\textit{, }\textbf{%    
1169  saltAdvection}\textit{\ }etc). These variables are all assumed here to be  \item[calculation of pressure/geopotential] \
1170  set to '.\texttt{TRUE}.'. Look at file \textit{model/inc/PARAMS.h }for a    
1171  precise definition.    First, to run a non-hydrostatic ocean simulation, set the logical
1172      variable \textbf{nonHydrostatic} to \texttt{'.TRUE.'}. The pressure
1173  \begin{itemize}    field is then inverted through a 3D elliptic equation. (Note: this
1174  \item initialization    capability is not available for the atmosphere yet.) By default, a
1175  \end{itemize}    hydrostatic simulation is assumed and a 2D elliptic equation is used
1176      to invert the pressure field. The parameters controlling the
1177  The initial tracer data can be contained in the binary files \textbf{%    behaviour of the elliptic solvers are the variables
1178  hydrogThetaFile }and \textbf{hydrogSaltFile}. These files should contain 3D    \textbf{cg2dMaxIters} and \textbf{cg2dTargetResidual } for
1179  data ordered in an (x, y, r) fashion with k=1 as the first vertical level.    the 2D case and \textbf{cg3dMaxIters} and
1180  If no file names are provided, the tracers are then initialized with the    \textbf{cg3dTargetResidual} for the 3D case. You probably won't need to
1181  values of \textbf{tRef }and \textbf{sRef }mentioned above (in the equation    alter the default values (are we sure of this?).
1182  of state section). In this case, the initial tracer data are uniform in x    
1183  and y for each depth level.    For the calculation of the surface pressure (for the ocean) or
1184      surface geopotential (for the atmosphere) you need to set the
1185  \begin{itemize}    logical variables \textbf{rigidLid} and \textbf{implicitFreeSurface}
1186  \item forcing    (set one to \texttt{'.TRUE.'} and the other to \texttt{'.FALSE.'}
1187  \end{itemize}    depending on how you want to deal with the ocean upper or atmosphere
1188      lower boundary).
1189  This part is more relevant for the ocean, the procedure for the atmosphere  
1190  not being completely stabilized at the moment.  \end{description}
1191    
1192  A combination of fluxes data and relaxation terms can be used for driving  \subsection{Tracer equations}
1193  the tracer equations. \ For potential temperature, heat flux data (in W/m$%  
1194  ^{2}$) can be stored in the 2D binary file \textbf{surfQfile}\textit{. }%  This section covers the tracer equations i.e. the potential
1195  Alternatively or in addition, the forcing can be specified through a  temperature equation and the salinity (for the ocean) or specific
1196  relaxation term. The SST data to which the model surface temperatures are  humidity (for the atmosphere) equation. As for the momentum equations,
1197  restored to are supposed to be stored in the 2D binary file \textbf{%  we only describe for now the parameters that you are likely to change.
1198  thetaClimFile}\textit{. }The corresponding relaxation time scale coefficient  The logical variables \textbf{tempDiffusion} \textbf{tempAdvection}
1199  is set through the variable \textbf{tauThetaClimRelax}\textit{\ }(in s). The  \textbf{tempForcing}, and \textbf{tempStepping} allow you to turn
1200  same procedure applies for salinity with the variable names \textbf{EmPmRfile%  on/off terms in the temperature equation (same thing for salinity or
1201  }\textit{, }\textbf{saltClimFile}\textit{, }and \textbf{tauSaltClimRelax}%  specific humidity with variables \textbf{saltDiffusion},
1202  \textit{\ }for freshwater flux (in m/s) and surface salinity (in ppt) data  \textbf{saltAdvection} etc.). These variables are all assumed here to
1203  files and relaxation time scale coefficient (in s), respectively. Also for  be set to \texttt{'.TRUE.'}. Look at file \textit{model/inc/PARAMS.h}
1204  salinity, if the CPP key \textbf{USE\_NATURAL\_BCS} is turned on, natural  for a precise definition.
1205  boundary conditions are applied i.e. when computing the surface salinity  
1206  tendency, the freshwater flux is multiplied by the model surface salinity  \begin{description}
1207  instead of a constant salinity value.  \item[initialization] \
1208      
1209  As for the other input files, the precision with which to read the data is    The initial tracer data can be contained in the binary files
1210  controlled by the variable \textbf{readBinaryPrec}. Time-dependent, periodic    \textbf{hydrogThetaFile} and \textbf{hydrogSaltFile}. These files
1211  forcing can be applied as well following the same procedure used for the    should contain 3D data ordered in an (x,y,r) fashion with k=1 as the
1212  wind forcing data (see above).    first vertical level.  If no file names are provided, the tracers
1213      are then initialized with the values of \textbf{tRef} and
1214  \begin{itemize}    \textbf{sRef} mentioned above (in the equation of state section). In
1215  \item dissipation    this case, the initial tracer data are uniform in x and y for each
1216  \end{itemize}    depth level.
1217    
1218  Lateral eddy diffusivities for temperature and salinity/specific humidity  \item[forcing] \
1219  are specified through the variables \textbf{diffKhT }and \textbf{diffKhS }%    
1220  (in m$^{2}$/s). Vertical eddy diffusivities are specified through the    This part is more relevant for the ocean, the procedure for the
1221  variables \textbf{diffKzT }and \textbf{diffKzS }(in m$^{2}$/s) for the ocean    atmosphere not being completely stabilized at the moment.
1222  and \textbf{diffKpT }and \textbf{diffKpS }(in Pa$^{2}$/s) for the    
1223  atmosphere. The vertical diffusive fluxes can be computed implicitly by    A combination of fluxes data and relaxation terms can be used for
1224  setting the logical variable \textbf{implicitDiffusion }to '.\texttt{TRUE}%    driving the tracer equations.  For potential temperature, heat flux
1225  .'. In addition, biharmonic diffusivities can be specified as well through    data (in W/m$ ^{2}$) can be stored in the 2D binary file
1226  the coefficients \textbf{diffK4T }and \textbf{diffK4S }(in m$^{4}$/s). Note    \textbf{surfQfile}.  Alternatively or in addition, the forcing can
1227  that the cosine power scaling (specified through \textbf{cosPower }- see the    be specified through a relaxation term. The SST data to which the
1228  momentum equations section) is applied to the tracer diffusivities    model surface temperatures are restored to are supposed to be stored
1229  (Laplacian and biharmonic) as well. The Gent and McWilliams parameterization    in the 2D binary file \textbf{thetaClimFile}. The corresponding
1230  for oceanic tracers is described in the package section. Finally, note that    relaxation time scale coefficient is set through the variable
1231  tracers can be also subject to Fourier and Shapiro filtering (see the    \textbf{tauThetaClimRelax} (in s). The same procedure applies for
1232  corresponding section on these filters).    salinity with the variable names \textbf{EmPmRfile},
1233      \textbf{saltClimFile}, and \textbf{tauSaltClimRelax} for freshwater
1234  \begin{itemize}    flux (in m/s) and surface salinity (in ppt) data files and
1235  \item ocean convection    relaxation time scale coefficient (in s), respectively. Also for
1236  \end{itemize}    salinity, if the CPP key \textbf{USE\_NATURAL\_BCS} is turned on,
1237      natural boundary conditions are applied i.e. when computing the
1238  Two options are available to parameterize ocean convection: one is to use    surface salinity tendency, the freshwater flux is multiplied by the
1239  the convective adjustment scheme. In this case, you need to set the variable    model surface salinity instead of a constant salinity value.
1240  \textbf{cadjFreq}, which represents the frequency (in s) with which the    
1241  adjustment algorithm is called, to a non-zero value (if set to a negative    As for the other input files, the precision with which to read the
1242  value by the user, the model will set it to the tracer time step). The other    data is controlled by the variable \textbf{readBinaryPrec}.
1243  option is to parameterize convection with implicit vertical diffusion. To do    Time-dependent, periodic forcing can be applied as well following
1244  this, set the logical variable \textbf{implicitDiffusion }to '.\texttt{TRUE}%    the same procedure used for the wind forcing data (see above).
1245  .' and the real variable \textbf{ivdc\_kappa }to a value (in m$^{2}$/s) you  
1246  wish the tracer vertical diffusivities to have when mixing tracers  \item[dissipation] \
1247  vertically due to static instabilities. Note that \textbf{cadjFreq }and    
1248  \textbf{ivdc\_kappa }can not both have non-zero value.    Lateral eddy diffusivities for temperature and salinity/specific
1249      humidity are specified through the variables \textbf{diffKhT} and
1250  \subsubsection{Simulation controls}    \textbf{diffKhS} (in m$^{2}$/s). Vertical eddy diffusivities are
1251      specified through the variables \textbf{diffKzT} and
1252  The model ''clock'' is defined by the variable \textbf{deltaTClock }(in s)    \textbf{diffKzS} (in m$^{2}$/s) for the ocean and \textbf{diffKpT
1253  which determines the IO frequencies and is used in tagging output.    }and \textbf{diffKpS} (in Pa$^{2}$/s) for the atmosphere. The
1254  Typically, you will set it to the tracer time step for accelerated runs    vertical diffusive fluxes can be computed implicitly by setting the
1255  (otherwise it is simply set to the default time step \textbf{deltaT}).    logical variable \textbf{implicitDiffusion} to \texttt{'.TRUE.'}.
1256  Frequency of checkpointing and dumping of the model state are referenced to    In addition, biharmonic diffusivities can be specified as well
1257  this clock (see below).    through the coefficients \textbf{diffK4T} and \textbf{diffK4S} (in
1258      m$^{4}$/s). Note that the cosine power scaling (specified through
1259  \begin{itemize}    \textbf{cosPower}---see the momentum equations section) is applied to
1260  \item run duration    the tracer diffusivities (Laplacian and biharmonic) as well. The
1261  \end{itemize}    Gent and McWilliams parameterization for oceanic tracers is
1262      described in the package section. Finally, note that tracers can be
1263  The beginning of a simulation is set by specifying a start time (in s)    also subject to Fourier and Shapiro filtering (see the corresponding
1264  through the real variable \textbf{startTime }or by specifying an initial    section on these filters).
1265  iteration number through the integer variable \textbf{nIter0}. If these  
1266  variables are set to nonzero values, the model will look for a ''pickup''  \item[ocean convection] \
1267  file \textit{pickup.0000nIter0 }to restart the integration\textit{. }The end    
1268  of a simulation is set through the real variable \textbf{endTime }(in s).    Two options are available to parameterize ocean convection: one is
1269  Alternatively, you can specify instead the number of time steps to execute    to use the convective adjustment scheme. In this case, you need to
1270  through the integer variable \textbf{nTimeSteps}.    set the variable \textbf{cadjFreq}, which represents the frequency
1271      (in s) with which the adjustment algorithm is called, to a non-zero
1272  \begin{itemize}    value (if set to a negative value by the user, the model will set it
1273  \item frequency of output    to the tracer time step). The other option is to parameterize
1274  \end{itemize}    convection with implicit vertical diffusion. To do this, set the
1275      logical variable \textbf{implicitDiffusion} to \texttt{'.TRUE.'}
1276  Real variables defining frequencies (in s) with which output files are    and the real variable \textbf{ivdc\_kappa} to a value (in m$^{2}$/s)
1277  written on disk need to be set up. \textbf{dumpFreq }controls the frequency    you wish the tracer vertical diffusivities to have when mixing
1278  with which the instantaneous state of the model is saved. \textbf{chkPtFreq }%    tracers vertically due to static instabilities. Note that
1279  and \textbf{pchkPtFreq }control the output frequency of rolling and    \textbf{cadjFreq} and \textbf{ivdc\_kappa}can not both have non-zero
1280  permanent checkpoint files, respectively. See section 1.5.1 Output files for the    value.
1281  definition of model state and checkpoint files. In addition, time-averaged  
1282  fields can be written out by setting the variable \textbf{taveFreq} (in s).  \end{description}
1283  The precision with which to write the binary data is controlled by the  
1284  integer variable w\textbf{riteBinaryPrec }(set it to \texttt{32} or \texttt{%  \subsection{Simulation controls}
1285  64}).  
1286    The model ''clock'' is defined by the variable \textbf{deltaTClock}
1287    (in s) which determines the IO frequencies and is used in tagging
1288    output.  Typically, you will set it to the tracer time step for
1289    accelerated runs (otherwise it is simply set to the default time step
1290    \textbf{deltaT}).  Frequency of checkpointing and dumping of the model
1291    state are referenced to this clock (see below).
1292    
1293    \begin{description}
1294    \item[run duration] \
1295      
1296      The beginning of a simulation is set by specifying a start time (in
1297      s) through the real variable \textbf{startTime} or by specifying an
1298      initial iteration number through the integer variable
1299      \textbf{nIter0}. If these variables are set to nonzero values, the
1300      model will look for a ''pickup'' file \textit{pickup.0000nIter0} to
1301      restart the integration. The end of a simulation is set through the
1302      real variable \textbf{endTime} (in s).  Alternatively, you can
1303      specify instead the number of time steps to execute through the
1304      integer variable \textbf{nTimeSteps}.
1305    
1306    \item[frequency of output] \
1307      
1308      Real variables defining frequencies (in s) with which output files
1309      are written on disk need to be set up. \textbf{dumpFreq} controls
1310      the frequency with which the instantaneous state of the model is
1311      saved. \textbf{chkPtFreq} and \textbf{pchkPtFreq} control the output
1312      frequency of rolling and permanent checkpoint files, respectively.
1313      See section 1.5.1 Output files for the definition of model state and
1314      checkpoint files. In addition, time-averaged fields can be written
1315      out by setting the variable \textbf{taveFreq} (in s).  The precision
1316      with which to write the binary data is controlled by the integer
1317      variable w\textbf{riteBinaryPrec} (set it to \texttt{32} or
1318      \texttt{64}).
1319    
1320    \end{description}
1321    
1322    
1323    %%% Local Variables:
1324    %%% mode: latex
1325    %%% TeX-master: t
1326    %%% End:

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