/[MITgcm]/manual/s_getstarted/text/getting_started.tex

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-revision 1.16 by edhill,
Thu Jan 29 03:02:33 2004 UTC
+revision 1.30 by edhill,
Sat Oct 16 03:40:13 2004 UTC
 Line 15 
 structure are described more fully in ch
  this section, we provide information on how to customize the code when
  you are ready to try implementing the configuration you have in mind.
  \section{Where to find information}
  \label{sect:whereToFindInfo}
+ \begin{rawhtml}
+ <!-- CMIREDIR:whereToFindInfo: -->
+ \end{rawhtml}
  A web site is maintained for release 2 (``Pelican'') of MITgcm:
  \begin{rawhtml} <A href=http://mitgcm.org/pelican/ target="idontexist"> \end{rawhtml}
-Line 50 
 http://mitgcm.org/htdig/
+Line 54 
 http://mitgcm.org/htdig/
  \section{Obtaining the code}
  \label{sect:obtainingCode}
+ \begin{rawhtml}
+ <!-- CMIREDIR:obtainingCode: -->
+ \end{rawhtml}
  MITgcm can be downloaded from our system by following
  the instructions below. As a courtesy we ask that you send e-mail to us at
-Line 79 
 provide easy support for maintenance upd
+Line 86 
 provide easy support for maintenance upd
  \end{enumerate}
+ \subsection{Method 1 - Checkout from CVS}
+ \label{sect:cvs_checkout}
  If CVS is available on your system, we strongly encourage you to use it. CVS
  provides an efficient and elegant way of organizing your code and keeping
  track of your changes. If CVS is not available on your machine, you can also
-Line 93 
 in your .cshrc or .tcshrc file.  For bas
+Line 103 
 in your .cshrc or .tcshrc file.  For bas
  \begin{verbatim}
  % export CVSROOT=':pserver:cvsanon@mitgcm.org:/u/gcmpack'
  \end{verbatim}
- in your .profile or .bashrc file.
+ in your \texttt{.profile} or \texttt{.bashrc} file.
  To get MITgcm through CVS, first register with the MITgcm CVS server
-Line 115 
 The MITgcm web site contains further dir
+Line 125 
 The MITgcm web site contains further dir
  code and CVS.  It also contains a web interface to our CVS archive so
  that one may easily view the state of files, revisions, and other
  development milestones:
- \begin{rawhtml} <A href=http://mitgcm.org/download target="idontexist"> \end{rawhtml}
+ \begin{rawhtml} <A href=''http://mitgcm.org/download'' target="idontexist"> \end{rawhtml}
  \begin{verbatim}
- http://mitgcm.org/source\_code.html
+ http://mitgcm.org/source_code.html
  \end{verbatim}
  \begin{rawhtml} </A> \end{rawhtml}
+ As a convenience, the MITgcm CVS server contains aliases which are
+ named subsets of the codebase.  These aliases can be especially
+ helpful when used over slow internet connections or on machines with
+ restricted storage space.  Table \ref{tab:cvsModules} contains a list
+ of CVS aliases
+ \begin{table}[htb]
+   \centering
+   \begin{tabular}[htb]{|lp{3.25in}|}\hline
+     \textbf{Alias Name}    &  \textbf{Information (directories) Contained}  \\\hline
+     \texttt{MITgcm\_code}  &  Only the source code -- none of the verification examples.  \\
+     \texttt{MITgcm\_verif\_basic}
+     &  Source code plus a small set of the verification examples
+     (\texttt{global\_ocean.90x40x15}, \texttt{aim.5l\_cs}, \texttt{hs94.128x64x5},
+     \texttt{front\_relax}, and \texttt{plume\_on\_slope}).  \\
+     \texttt{MITgcm\_verif\_atmos}  &  Source code plus all of the atmospheric examples.  \\
+     \texttt{MITgcm\_verif\_ocean}  &  Source code plus all of the oceanic examples.  \\
+     \texttt{MITgcm\_verif\_all}    &  Source code plus all of the
+     verification examples. \\\hline
+   \end{tabular}
+   \caption{MITgcm CVS Modules}
+   \label{tab:cvsModules}
+ \end{table}
  The checkout process creates a directory called \textit{MITgcm}. If
  the directory \textit{MITgcm} exists this command updates your code
-Line 130 
 track of your file versions with respect
+Line 162 
 track of your file versions with respect
  the files in \textit{CVS}!  You can also use CVS to download code
  updates.  More extensive information on using CVS for maintaining
  MITgcm code can be found
- \begin{rawhtml} <A href=http://mitgcm.org/usingcvstoget.html target="idontexist"> \end{rawhtml}
+ \begin{rawhtml} <A href=''http://mitgcm.org/usingcvstoget.html'' target="idontexist"> \end{rawhtml}
  here
  \begin{rawhtml} </A> \end{rawhtml}
  .
+ It is important to note that the CVS aliases in Table
+ \ref{tab:cvsModules} cannot be used in conjunction with the CVS
+ \texttt{-d DIRNAME} option.  However, the \texttt{MITgcm} directories
+ they create can be changed to a different name following the check-out:
+ \begin{verbatim}
+    %  cvs co MITgcm_verif_basic
+    %  mv MITgcm MITgcm_verif_basic
+ \end{verbatim}
- \paragraph*{Conventional download method}
+ \subsection{Method 2 - Tar file download}
  \label{sect:conventionalDownload}
  If you do not have CVS on your system, you can download the model as a
-Line 150 
 The tar file still contains CVS informat
+Line 190 
 The tar file still contains CVS informat
  delete; even if you do not use CVS yourself the information can help
  us if you should need to send us your copy of the code.  If a recent
  tar file does not exist, then please contact the developers through
- the MITgcm-support list.
+ the
+ \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
+ MITgcm-support@mitgcm.org
+ \begin{rawhtml} </A> \end{rawhtml}
+ mailing list.
- \paragraph*{Upgrading from an earlier version}
+ \subsubsection{Upgrading from an earlier version}
  If you already have an earlier version of the code you can ``upgrade''
  your copy instead of downloading the entire repository again. First,
-Line 178 
 If the list of conflicts scrolled off th
+Line 222 
 If the list of conflicts scrolled off th
  cvs update command and it will report the conflicts. Conflicts are
  indicated in the code by the delimites ``$<<<<<<<$'', ``======='' and
  ``$>>>>>>>$''. For example,
+ {\small
  \begin{verbatim}
  <<<<<<< ini_parms.F
       & bottomDragLinear,myOwnBottomDragCoefficient,
-Line 185 
 indicated in the code by the delimites `
+Line 230 
 indicated in the code by the delimites `
       & bottomDragLinear,bottomDragQuadratic,
  >>>>>>> 1.18
  \end{verbatim}
+ }
  means that you added ``myOwnBottomDragCoefficient'' to a namelist at
  the same time and place that we added ``bottomDragQuadratic''. You
  need to resolve this conflict and in this case the line should be
  changed to:
+ {\small
  \begin{verbatim}
       & bottomDragLinear,bottomDragQuadratic,myOwnBottomDragCoefficient,
  \end{verbatim}
+ }
  and the lines with the delimiters ($<<<<<<$,======,$>>>>>>$) be deleted.
  Unless you are making modifications which exactly parallel
  developments we make, these types of conflicts should be rare.
-Line 215 
 also means we can't tell what version of
+Line 263 
 also means we can't tell what version of
  with. So please be sure you understand what you're doing.
  \section{Model and directory structure}
+ \begin{rawhtml}
+ <!-- CMIREDIR:directory_structure: -->
+ \end{rawhtml}
  The ``numerical'' model is contained within a execution environment
  support wrapper. This wrapper is designed to provide a general
-Line 225 
 model code. The execution environment su
+Line 276 
 model code. The execution environment su
  \textit{eesupp} directory. The grid point model code is held under the
  \textit{model} directory. Code execution actually starts in the
  \textit{eesupp} routines and not in the \textit{model} routines. For
- this reason the top-level
+ this reason the top-level \textit{MAIN.F} is in the
- \textit{MAIN.F} is in the \textit{eesupp/src} directory. In general,
+ \textit{eesupp/src} directory. In general, end-users should not need
- end-users should not need to worry about this level. The top-level routine
+ to worry about this level. The top-level routine for the numerical
- for the numerical part of the code is in \textit{model/src/THE\_MODEL\_MAIN.F%
+ part of the code is in \textit{model/src/THE\_MODEL\_MAIN.F}. Here is
- }. Here is a brief description of the directory structure of the model under
+ a brief description of the directory structure of the model under the
- the root tree (a detailed description is given in section 3: Code structure).
+ root tree (a detailed description is given in section 3: Code
+ structure).
  \begin{itemize}
- \item \textit{bin}: this directory is initially empty. It is the default
- directory in which to compile the code.
+ \item \textit{bin}: this directory is initially empty. It is the
+   default directory in which to compile the code.
  \item \textit{diags}: contains the code relative to time-averaged
- diagnostics. It is subdivided into two subdirectories \textit{inc} and
+   diagnostics. It is subdivided into two subdirectories \textit{inc}
- \textit{src} that contain include files (*.\textit{h} files) and Fortran
+   and \textit{src} that contain include files (*.\textit{h} files) and
- subroutines (*.\textit{F} files), respectively.
+   Fortran subroutines (*.\textit{F} files), respectively.
  \item \textit{doc}: contains brief documentation notes.
- \item \textit{eesupp}: contains the execution environment source code. Also
+ \item \textit{eesupp}: contains the execution environment source code.
- subdivided into two subdirectories \textit{inc} and \textit{src}.
+   Also subdivided into two subdirectories \textit{inc} and
+   \textit{src}.
- \item \textit{exe}: this directory is initially empty. It is the default
- directory in which to execute the code.
+ \item \textit{exe}: this directory is initially empty. It is the
+   default directory in which to execute the code.
- \item \textit{model}: this directory contains the main source code. Also
- subdivided into two subdirectories \textit{inc} and \textit{src}.
+ \item \textit{model}: this directory contains the main source code.
+   Also subdivided into two subdirectories \textit{inc} and
- \item \textit{pkg}: contains the source code for the packages. Each package
+   \textit{src}.
- corresponds to a subdirectory. For example, \textit{gmredi} contains the
- code related to the Gent-McWilliams/Redi scheme, \textit{aim} the code
+ \item \textit{pkg}: contains the source code for the packages. Each
- relative to the atmospheric intermediate physics. The packages are described
+   package corresponds to a subdirectory. For example, \textit{gmredi}
- in detail in section 3.
+   contains the code related to the Gent-McWilliams/Redi scheme,
+   \textit{aim} the code relative to the atmospheric intermediate
- \item \textit{tools}: this directory contains various useful tools. For
+   physics. The packages are described in detail in section 3.
- example, \textit{genmake2} is a script written in csh (C-shell) that should
- be used to generate your makefile. The directory \textit{adjoint} contains
+ \item \textit{tools}: this directory contains various useful tools.
- the makefile specific to the Tangent linear and Adjoint Compiler (TAMC) that
+   For example, \textit{genmake2} is a script written in csh (C-shell)
- generates the adjoint code. The latter is described in details in part V.
+   that should be used to generate your makefile. The directory
+   \textit{adjoint} contains the makefile specific to the Tangent
+   linear and Adjoint Compiler (TAMC) that generates the adjoint code.
+   The latter is described in details in part V.
  \item \textit{utils}: this directory contains various utilities. The
- subdirectory \textit{knudsen2} contains code and a makefile that
+   subdirectory \textit{knudsen2} contains code and a makefile that
- compute coefficients of the polynomial approximation to the knudsen
+   compute coefficients of the polynomial approximation to the knudsen
- formula for an ocean nonlinear equation of state. The \textit{matlab}
+   formula for an ocean nonlinear equation of state. The
- subdirectory contains matlab scripts for reading model output directly
+   \textit{matlab} subdirectory contains matlab scripts for reading
- into matlab. \textit{scripts} contains C-shell post-processing
+   model output directly into matlab. \textit{scripts} contains C-shell
- scripts for joining processor-based and tiled-based model output.
+   post-processing scripts for joining processor-based and tiled-based
+   model output.
+ \item \textit{verification}: this directory contains the model
+   examples. See section \ref{sect:modelExamples}.
- \item \textit{verification}: this directory contains the model examples. See
- section \ref{sect:modelExamples}.
  \end{itemize}
- \section{Example experiments}
+ \section[MITgcm Example Experiments]{Example experiments}
  \label{sect:modelExamples}
+ \begin{rawhtml}
+ <!-- CMIREDIR:modelExamples: -->
+ \end{rawhtml}
  %% a set of twenty-four pre-configured numerical experiments
-Line 295 
 below.
+Line 356 
 below.
  \subsection{Full list of model examples}
  \begin{enumerate}
  \item \textit{exp0} - single layer, ocean double gyre (barotropic with
    free-surface). This experiment is described in detail in section
    \ref{sect:eg-baro}.
-Line 420 
 Each example directory has the following
+Line 482 
 Each example directory has the following
      of the number of threads to use in $X$ and $Y$ under multithreaded
      execution.
    \end{itemize}
- In addition, you will also find in this directory the forcing and
+   In addition, you will also find in this directory the forcing and
- topography files as well as the files describing the initial state of
+   topography files as well as the files describing the initial state
- the experiment.  This varies from experiment to experiment. See
+   of the experiment.  This varies from experiment to experiment. See
- section 2 for more details.
+   section 2 for more details.
  \item \textit{results}: this directory contains the output file
    \textit{output.txt} produced by the simulation example. This file is
-Line 432 
 section 2 for more details.
+Line 494 
 section 2 for more details.
    experiment.
  \end{itemize}
- Once you have chosen the example you want to run, you are ready to compile
+ Once you have chosen the example you want to run, you are ready to
- the code.
+ compile the code.
- \section{Building the code}
+ \section[Building MITgcm]{Building the code}
  \label{sect:buildingCode}
+ \begin{rawhtml}
+ <!-- CMIREDIR:buildingCode: -->
+ \end{rawhtml}
  To compile the code, we use the {\em make} program. This uses a file
  ({\em Makefile}) that allows us to pre-process source files, specify
-Line 458 
 First, build the {\em Makefile}:
+Line 523 
 First, build the {\em Makefile}:
  % ../../../tools/genmake2 -mods=../code
  \end{verbatim}
  The command line option tells {\em genmake} to override model source
- code with any files in the directory {\em ./code/}.
+ code with any files in the directory {\em ../code/}.
  On many systems, the {\em genmake2} program will be able to
  automatically recognize the hardware, find compilers and other tools
  within the user's path (``echo \$PATH''), and then choose an
- appropriate set of options from the files contained in the {\em
+ appropriate set of options from the files (``optfiles'') contained in
-   tools/build\_options} directory.  Under some circumstances, a user
+ the {\em tools/build\_options} directory.  Under some circumstances, a
- may have to create a new ``optfile'' in order to specify the exact
+ user may have to create a new ``optfile'' in order to specify the
- combination of compiler, compiler flags, libraries, and other options
+ exact combination of compiler, compiler flags, libraries, and other
- necessary to build a particular configuration of MITgcm.  In such
+ options necessary to build a particular configuration of MITgcm.  In
- cases, it is generally helpful to read the existing ``optfiles'' and
+ such cases, it is generally helpful to read the existing ``optfiles''
- mimic their syntax.
+ and mimic their syntax.
  Through the MITgcm-support list, the MITgcm developers are willing to
  provide help writing or modifing ``optfiles''.  And we encourage users
  to post new ``optfiles'' (particularly ones for new machines or
- architectures) to the MITgcm-support list.
+ architectures) to the
+ \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
+ MITgcm-support@mitgcm.org
+ \begin{rawhtml} </A> \end{rawhtml}
+ list.
  To specify an optfile to {\em genmake2}, the syntax is:
  \begin{verbatim}
-Line 489 
 This modifies the {\em Makefile} by atta
+Line 558 
 This modifies the {\em Makefile} by atta
  upon which other files depend. The purpose of this is to reduce
  re-compilation if and when you start to modify the code. The {\tt make
    depend} command also creates links from the model source to this
- directory.
+ directory.  It is important to note that the {\tt make depend} stage
+ will occasionally produce warnings or errors since the dependency
+ parsing tool is unable to find all of the necessary header files
+ (\textit{eg.}  \texttt{netcdf.inc}).  In these circumstances, it is
+ usually OK to ignore the warnings/errors and proceed to the next step.
  Next compile the code:
  \begin{verbatim}
-Line 508 
 where we are re-directing the stream of
+Line 581 
 where we are re-directing the stream of
  output.txt}.
- \subsection{Building/compiling the code elsewhere}
+ \section[Running MITgcm]{Running the model in prognostic mode}
- In the example above (section \ref{sect:buildingCode}) we built the
- executable in the {\em input} directory of the experiment for
- convenience. You can also configure and compile the code in other
- locations, for example on a scratch disk with out having to copy the
- entire source tree. The only requirement to do so is you have {\tt
-   genmake2} in your path or you know the absolute path to {\tt
-   genmake2}.
- The following sections outline some possible methods of organizing
- your source and data.
- \subsubsection{Building from the {\em ../code directory}}
- This is just as simple as building in the {\em input/} directory:
- \begin{verbatim}
- % cd verification/exp2/code
- % ../../../tools/genmake2
- % make depend
- % make
- \end{verbatim}
- However, to run the model the executable ({\em mitgcmuv}) and input
- files must be in the same place. If you only have one calculation to make:
- \begin{verbatim}
- % cd ../input
- % cp ../code/mitgcmuv ./
- % ./mitgcmuv > output.txt
- \end{verbatim}
- or if you will be making multiple runs with the same executable:
- \begin{verbatim}
- % cd ../
- % cp -r input run1
- % cp code/mitgcmuv run1
- % cd run1
- % ./mitgcmuv > output.txt
- \end{verbatim}
- \subsubsection{Building from a new directory}
- Since the {\em input} directory contains input files it is often more
- useful to keep {\em input} pristine and build in a new directory
- within {\em verification/exp2/}:
- \begin{verbatim}
- % cd verification/exp2
- % mkdir build
- % cd build
- % ../../../tools/genmake2 -mods=../code
- % make depend
- % make
- \end{verbatim}
- This builds the code exactly as before but this time you need to copy
- either the executable or the input files or both in order to run the
- model. For example,
- \begin{verbatim}
- % cp ../input/* ./
- % ./mitgcmuv > output.txt
- \end{verbatim}
- or if you tend to make multiple runs with the same executable then
- running in a new directory each time might be more appropriate:
- \begin{verbatim}
- % cd ../
- % mkdir run1
- % cp build/mitgcmuv run1/
- % cp input/* run1/
- % cd run1
- % ./mitgcmuv > output.txt
- \end{verbatim}
- \subsubsection{Building on a scratch disk}
- Model object files and output data can use up large amounts of disk
- space so it is often the case that you will be operating on a large
- scratch disk. Assuming the model source is in {\em ~/MITgcm} then the
- following commands will build the model in {\em /scratch/exp2-run1}:
- \begin{verbatim}
- % cd /scratch/exp2-run1
- % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
-   -mods=~/MITgcm/verification/exp2/code
- % make depend
- % make
- \end{verbatim}
- To run the model here, you'll need the input files:
- \begin{verbatim}
- % cp ~/MITgcm/verification/exp2/input/* ./
- % ./mitgcmuv > output.txt
- \end{verbatim}
- As before, you could build in one directory and make multiple runs of
- the one experiment:
- \begin{verbatim}
- % cd /scratch/exp2
- % mkdir build
- % cd build
- % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \
-   -mods=~/MITgcm/verification/exp2/code
- % make depend
- % make
- % cd ../
- % cp -r ~/MITgcm/verification/exp2/input run2
- % cd run2
- % ./mitgcmuv > output.txt
- \end{verbatim}
- \subsection{Using \textit{genmake2}}
- \label{sect:genmake}
- To compile the code, first use the program \texttt{genmake2} (located
- in the \textit{tools} directory) to generate a Makefile.
- \texttt{genmake2} is a shell script written to work with all
- ``sh''--compatible shells including bash v1, bash v2, and Bourne.
- Internally, \texttt{genmake2} determines the locations of needed
- files, the compiler, compiler options, libraries, and Unix tools.  It
- relies upon a number of ``optfiles'' located in the {\em
-   tools/build\_options} directory.
- The purpose of the optfiles is to provide all the compilation options
- for particular ``platforms'' (where ``platform'' roughly means the
- combination of the hardware and the compiler) and code configurations.
- Given the combinations of possible compilers and library dependencies
- ({\it eg.}  MPI and NetCDF) there may be numerous optfiles available
- for a single machine.  The naming scheme for the majority of the
- optfiles shipped with the code is
- \begin{center}
-   {\bf OS\_HARDWARE\_COMPILER }
- \end{center}
- where
- \begin{description}
- \item[OS] is the name of the operating system (generally the
-   lower-case output of the {\tt 'uname'} command)
- \item[HARDWARE] is a string that describes the CPU type and
-   corresponds to output from the  {\tt 'uname -m'} command:
-   \begin{description}
-   \item[ia32] is for ``x86'' machines such as i386, i486, i586, i686,
-     and athlon
-   \item[ia64] is for Intel IA64 systems (eg. Itanium, Itanium2)
-   \item[amd64] is AMD x86\_64 systems
-   \item[ppc] is for Mac PowerPC systems
-   \end{description}
- \item[COMPILER] is the compiler name (generally, the name of the
-   FORTRAN executable)
- \end{description}
- In many cases, the default optfiles are sufficient and will result in
- usable Makefiles.  However, for some machines or code configurations,
- new ``optfiles'' must be written. To create a new optfile, it is
- generally best to start with one of the defaults and modify it to suit
- your needs.  Like \texttt{genmake2}, the optfiles are all written
- using a simple ``sh''--compatible syntax.  While nearly all variables
- used within \texttt{genmake2} may be specified in the optfiles, the
- critical ones that should be defined are:
- \begin{description}
- \item[FC] the FORTRAN compiler (executable) to use
- \item[DEFINES] the command-line DEFINE options passed to the compiler
- \item[CPP] the C pre-processor to use
- \item[NOOPTFLAGS] options flags for special files that should not be
-   optimized
- \end{description}
- For example, the optfile for a typical Red Hat Linux machine (``ia32''
- architecture) using the GCC (g77) compiler is
- \begin{verbatim}
- FC=g77
- DEFINES='-D_BYTESWAPIO -DWORDLENGTH=4'
- CPP='cpp  -traditional -P'
- NOOPTFLAGS='-O0'
- #  For IEEE, use the "-ffloat-store" option
- if test "x$IEEE" = x ; then
-     FFLAGS='-Wimplicit -Wunused -Wuninitialized'
-     FOPTIM='-O3 -malign-double -funroll-loops'
- else
-     FFLAGS='-Wimplicit -Wunused -ffloat-store'
-     FOPTIM='-O0 -malign-double'
- fi
- \end{verbatim}
- If you write an optfile for an unrepresented machine or compiler, you
- are strongly encouraged to submit the optfile to the MITgcm project
- for inclusion.  Please send the file to the
- \begin{rawhtml} <A href="mail-to:MITgcm-support@mitgcm.org"> \end{rawhtml}
- \begin{center}
-   MITgcm-support@mitgcm.org
- \end{center}
- \begin{rawhtml} </A> \end{rawhtml}
- mailing list.
- In addition to the optfiles, \texttt{genmake2} supports a number of
- helpful command-line options.  A complete list of these options can be
- obtained from:
- \begin{verbatim}
- % genmake2 -h
- \end{verbatim}
- The most important command-line options are:
- \begin{description}
- \item[--optfile=/PATH/FILENAME] specifies the optfile that should be
-   used for a particular build.
-   If no "optfile" is specified (either through the command line or the
-   MITGCM\_OPTFILE environment variable), genmake2 will try to make a
-   reasonable guess from the list provided in {\em
-     tools/build\_options}.  The method used for making this guess is
-   to first determine the combination of operating system and hardware
-   (eg. "linux\_ia32") and then find a working FORTRAN compiler within
-   the user's path.  When these three items have been identified,
-   genmake2 will try to find an optfile that has a matching name.
- \item[--pdepend=/PATH/FILENAME] specifies the dependency file used for
-   packages.
-   If not specified, the default dependency file {\em pkg/pkg\_depend}
-   is used.  The syntax for this file is parsed on a line-by-line basis
-   where each line containes either a comment ("\#") or a simple
-   "PKGNAME1 (+|-)PKGNAME2" pairwise rule where the "+" or "-" symbol
-   specifies a "must be used with" or a "must not be used with"
-   relationship, respectively.  If no rule is specified, then it is
-   assumed that the two packages are compatible and will function
-   either with or without each other.
- \item[--pdefault='PKG1 PKG2 PKG3 ...'] specifies the default set of
-   packages to be used.
-   If not set, the default package list will be read from {\em
-     pkg/pkg\_default}
- \item[--adof=/path/to/file] specifies the "adjoint" or automatic
-   differentiation options file to be used.  The file is analogous to
-   the ``optfile'' defined above but it specifies information for the
-   AD build process.
-   The default file is located in {\em
-     tools/adjoint\_options/adjoint\_default} and it defines the "TAF"
-   and "TAMC" compilers.  An alternate version is also available at
-   {\em tools/adjoint\_options/adjoint\_staf} that selects the newer
-   "STAF" compiler.  As with any compilers, it is helpful to have their
-   directories listed in your {\tt \$PATH} environment variable.
- \item[--mods='DIR1 DIR2 DIR3 ...'] specifies a list of directories
-   containing ``modifications''.  These directories contain files with
-   names that may (or may not) exist in the main MITgcm source tree but
-   will be overridden by any identically-named sources within the
-   ``MODS'' directories.
-   The order of precedence for this "name-hiding" is as follows:
-   \begin{itemize}
-   \item ``MODS'' directories (in the order given)
-   \item Packages either explicitly specified or provided by default
-     (in the order given)
-   \item Packages included due to package dependencies (in the order
-     that that package dependencies are parsed)
-   \item The "standard dirs" (which may have been specified by the
-     ``-standarddirs'' option)
-   \end{itemize}
- \item[--make=/path/to/gmake] Due to the poor handling of soft-links and
-   other bugs common with the \texttt{make} versions provided by
-   commercial Unix vendors, GNU \texttt{make} (sometimes called
-   \texttt{gmake}) should be preferred.  This option provides a means
-   for specifying the make executable to be used.
- \end{description}
- \section{Running the model}
  \label{sect:runModel}
+ \begin{rawhtml}
+ <!-- CMIREDIR:runModel: -->
+ \end{rawhtml}
+ If compilation finished succesfuully (section \ref{sect:buildingCode})
+ then an executable called \texttt{mitgcmuv} will now exist in the
+ local directory.
- If compilation finished succesfuully (section \ref{sect:buildModel})
+ To run the model as a single process (\textit{ie.} not in parallel)
- then an executable called {\em mitgcmuv} will now exist in the local
+ simply type:
- directory.
- To run the model as a single process (ie. not in parallel) simply
- type:
  \begin{verbatim}
  % ./mitgcmuv
  \end{verbatim}
-Line 798 
 normally re-direct the {\em stdout} stre
+Line 606 
 normally re-direct the {\em stdout} stre
  \begin{verbatim}
  % ./mitgcmuv > output.txt
  \end{verbatim}
+ In the event that the model encounters an error and stops, it is very
- For the example experiments in {\em vericication}, an example of the
+ helpful to include the last few line of this \texttt{output.txt} file
- output is kept in {\em results/output.txt} for comparison. You can compare
+ along with the (\texttt{stderr}) error message within any bug reports.
- your {\em output.txt} with this one to check that the set-up works.
+ For the example experiments in {\em verification}, an example of the
+ output is kept in {\em results/output.txt} for comparison. You can
+ compare your {\em output.txt} with the corresponding one for that
+ experiment to check that the set-up works.
  \subsection{Output files}
- The model produces various output files. At a minimum, the instantaneous
+ The model produces various output files.  Depending upon the I/O
- ``state'' of the model is written out, which is made of the following files:
+ package selected (either \texttt{mdsio} or \texttt{mnc} or both as
+ determined by both the compile-time settings and the run-time flags in
+ \texttt{data.pkg}), the following output may appear.
+ \subsubsection{MDSIO output files}
+ The ``traditional'' output files are generated by the \texttt{mdsio}
+ package.  At a minimum, the instantaneous ``state'' of the model is
+ written out, which is made of the following files:
  \begin{itemize}
  \item \textit{U.00000nIter} - zonal component of velocity field (m/s and $>
-Line 856 
 as the pickup files but are named differ
+Line 677 
 as the pickup files but are named differ
  used to restart the model but are overwritten every other time they are
  output to save disk space during long integrations.
+ \subsubsection{MNC output files}
+ Unlike the \texttt{mdsio} output, the \texttt{mnc}--generated output
+ is usually (though not necessarily) placed within a subdirectory with
+ a name such as \texttt{mnc\_test\_\${DATE}\_\${SEQ}}.  The files
+ within this subdirectory are all in the ``self-describing'' netCDF
+ format and can thus be browsed and/or plotted using tools such as:
+ \begin{itemize}
+ \item At a minimum, the \texttt{ncdump} utility is typically included
+   with every netCDF install:
+   \begin{rawhtml} <A href="http://www.unidata.ucar.edu/packages/netcdf/"> \end{rawhtml}
+ \begin{verbatim}
+ http://www.unidata.ucar.edu/packages/netcdf/
+ \end{verbatim}
+   \begin{rawhtml} </A> \end{rawhtml}
+ \item The \texttt{ncview} utility is a very convenient and quick way
+   to plot netCDF data and it runs on most OSes:
+   \begin{rawhtml} <A href="http://meteora.ucsd.edu/~pierce/ncview_home_page.html"> \end{rawhtml}
+ \begin{verbatim}
+ http://meteora.ucsd.edu/~pierce/ncview_home_page.html
+ \end{verbatim}
+   \begin{rawhtml} </A> \end{rawhtml}
+ \item MatLAB(c) and other common post-processing environments provide
+   various netCDF interfaces including:
+   \begin{rawhtml} <A href="http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html"> \end{rawhtml}
+ \begin{verbatim}
+ http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html
+ \end{verbatim}
+   \begin{rawhtml} </A> \end{rawhtml}
+ \end{itemize}
  \subsection{Looking at the output}
- All the model data are written according to a ``meta/data'' file format.
+ The ``traditional'' or mdsio model data are written according to a
- Each variable is associated with two files with suffix names \textit{.data}
+ ``meta/data'' file format.  Each variable is associated with two files
- and \textit{.meta}. The \textit{.data} file contains the data written in
+ with suffix names \textit{.data} and \textit{.meta}. The
- binary form (big\_endian by default). The \textit{.meta} file is a
+ \textit{.data} file contains the data written in binary form
- ``header'' file that contains information about the size and the structure
+ (big\_endian by default). The \textit{.meta} file is a ``header'' file
- of the \textit{.data} file. This way of organizing the output is
+ that contains information about the size and the structure of the
- particularly useful when running multi-processors calculations. The base
+ \textit{.data} file. This way of organizing the output is particularly
- version of the model includes a few matlab utilities to read output files
+ useful when running multi-processors calculations. The base version of
- written in this format. The matlab scripts are located in the directory
+ the model includes a few matlab utilities to read output files written
- \textit{utils/matlab} under the root tree. The script \textit{rdmds.m} reads
+ in this format. The matlab scripts are located in the directory
- the data. Look at the comments inside the script to see how to use it.
+ \textit{utils/matlab} under the root tree. The script \textit{rdmds.m}
+ reads the data. Look at the comments inside the script to see how to
+ use it.
  Some examples of reading and visualizing some output in {\em Matlab}:
  \begin{verbatim}
-Line 885 
 Some examples of reading and visualizing
+Line 745 
 Some examples of reading and visualizing
  >> for n=1:11; imagesc(eta(:,:,n)');axis ij;colorbar;pause(.5);end
  \end{verbatim}
- \section{Doing it yourself: customizing the code}
+ Similar scripts for netCDF output (\texttt{rdmnc.m}) are available.
- When you are ready to run the model in the configuration you want, the
- easiest thing is to use and adapt the setup of the case studies experiment
- (described previously) that is the closest to your configuration. Then, the
- amount of setup will be minimized. In this section, we focus on the setup
- relative to the ''numerical model'' part of the code (the setup relative to
- the ''execution environment'' part is covered in the parallel implementation
- section) and on the variables and parameters that you are likely to change.
- \subsection{Configuration and setup}
- The CPP keys relative to the ''numerical model'' part of the code are all
- defined and set in the file \textit{CPP\_OPTIONS.h }in the directory \textit{%
- model/inc }or in one of the \textit{code }directories of the case study
- experiments under \textit{verification.} The model parameters are defined
- and declared in the file \textit{model/inc/PARAMS.h }and their default
- values are set in the routine \textit{model/src/set\_defaults.F. }The
- default values can be modified in the namelist file \textit{data }which
- needs to be located in the directory where you will run the model. The
- parameters are initialized in the routine \textit{model/src/ini\_parms.F}.
- Look at this routine to see in what part of the namelist the parameters are
- located.
- In what follows the parameters are grouped into categories related to the
- computational domain, the equations solved in the model, and the simulation
- controls.
- \subsection{Computational domain, geometry and time-discretization}
- \begin{itemize}
- \item dimensions
- \end{itemize}
- The number of points in the x, y,\textit{\ }and r\textit{\ }directions are
- represented by the variables \textbf{sNx}\textit{, }\textbf{sNy}\textit{, }%
- and \textbf{Nr}\textit{\ }respectively which are declared and set in the
- file \textit{model/inc/SIZE.h. }(Again, this assumes a mono-processor
- calculation. For multiprocessor calculations see section on parallel
- implementation.)
- \begin{itemize}
- \item grid
- \end{itemize}
- Three different grids are available: cartesian, spherical polar, and
- curvilinear (including the cubed sphere). The grid is set through the
- logical variables \textbf{usingCartesianGrid}\textit{, }\textbf{%
- usingSphericalPolarGrid}\textit{, }and \textit{\ }\textbf{%
- usingCurvilinearGrid}\textit{. }In the case of spherical and curvilinear
- grids, the southern boundary is defined through the variable \textbf{phiMin}%
- \textit{\ }which corresponds to the latitude of the southern most cell face
- (in degrees). The resolution along the x and y directions is controlled by
- the 1D arrays \textbf{delx}\textit{\ }and \textbf{dely}\textit{\ }(in meters
- in the case of a cartesian grid, in degrees otherwise). The vertical grid
- spacing is set through the 1D array \textbf{delz }for the ocean (in meters)
- or \textbf{delp}\textit{\ }for the atmosphere (in Pa). The variable \textbf{%
- Ro\_SeaLevel} represents the standard position of Sea-Level in ''R''
- coordinate. This is typically set to 0m for the ocean (default value) and 10$%
- ^{5}$Pa for the atmosphere. For the atmosphere, also set the logical
- variable \textbf{groundAtK1} to '.\texttt{TRUE}.'. which put the first level
- (k=1) at the lower boundary (ground).
- For the cartesian grid case, the Coriolis parameter $f$ is set through the
- variables \textbf{f0}\textit{\ }and \textbf{beta}\textit{\ }which correspond
- to the reference Coriolis parameter (in s$^{-1}$) and $\frac{\partial f}{%
- \partial y}$(in m$^{-1}$s$^{-1}$) respectively. If \textbf{beta }\textit{\ }%
- is set to a nonzero value, \textbf{f0}\textit{\ }is the value of $f$ at the
- southern edge of the domain.
- \begin{itemize}
- \item topography - full and partial cells
- \end{itemize}
- The domain bathymetry is read from a file that contains a 2D (x,y) map of
- depths (in m) for the ocean or pressures (in Pa) for the atmosphere. The
- file name is represented by the variable \textbf{bathyFile}\textit{. }The
- file is assumed to contain binary numbers giving the depth (pressure) of the
- model at each grid cell, ordered with the x coordinate varying fastest. The
- points are ordered from low coordinate to high coordinate for both axes. The
- model code applies without modification to enclosed, periodic, and double
- periodic domains. Periodicity is assumed by default and is suppressed by
- setting the depths to 0m for the cells at the limits of the computational
- domain (note: not sure this is the case for the atmosphere). The precision
- with which to read the binary data is controlled by the integer variable
- \textbf{readBinaryPrec }which can take the value \texttt{32} (single
- precision) or \texttt{64} (double precision). See the matlab program \textit{%
- gendata.m }in the \textit{input }directories under \textit{verification }to
- see how the bathymetry files are generated for the case study experiments.
- To use the partial cell capability, the variable \textbf{hFacMin}\textit{\ }%
- needs to be set to a value between 0 and 1 (it is set to 1 by default)
- corresponding to the minimum fractional size of the cell. For example if the
- bottom cell is 500m thick and \textbf{hFacMin}\textit{\ }is set to 0.1, the
- actual thickness of the cell (i.e. used in the code) can cover a range of
- discrete values 50m apart from 50m to 500m depending on the value of the
- bottom depth (in \textbf{bathyFile}) at this point.
- Note that the bottom depths (or pressures) need not coincide with the models
- levels as deduced from \textbf{delz}\textit{\ }or\textit{\ }\textbf{delp}%
- \textit{. }The model will interpolate the numbers in \textbf{bathyFile}%
- \textit{\ }so that they match the levels obtained from \textbf{delz}\textit{%
- \ }or\textit{\ }\textbf{delp}\textit{\ }and \textbf{hFacMin}\textit{. }
- (Note: the atmospheric case is a bit more complicated than what is written
- here I think. To come soon...)
- \begin{itemize}
- \item time-discretization
- \end{itemize}
- The time steps are set through the real variables \textbf{deltaTMom}
- and \textbf{deltaTtracer} (in s) which represent the time step for the
- momentum and tracer equations, respectively. For synchronous
- integrations, simply set the two variables to the same value (or you
- can prescribe one time step only through the variable
- \textbf{deltaT}). The Adams-Bashforth stabilizing parameter is set
- through the variable \textbf{abEps} (dimensionless). The stagger
- baroclinic time stepping can be activated by setting the logical
- variable \textbf{staggerTimeStep} to '.\texttt{TRUE}.'.
- \subsection{Equation of state}
- First, because the model equations are written in terms of
- perturbations, a reference thermodynamic state needs to be specified.
- This is done through the 1D arrays \textbf{tRef} and \textbf{sRef}.
- \textbf{tRef} specifies the reference potential temperature profile
- (in $^{o}$C for the ocean and $^{o}$K for the atmosphere) starting
- from the level k=1. Similarly, \textbf{sRef} specifies the reference
- salinity profile (in ppt) for the ocean or the reference specific
- humidity profile (in g/kg) for the atmosphere.
- The form of the equation of state is controlled by the character
- variables \textbf{buoyancyRelation} and \textbf{eosType}.
- \textbf{buoyancyRelation} is set to '\texttt{OCEANIC}' by default and
- needs to be set to '\texttt{ATMOSPHERIC}' for atmosphere simulations.
- In this case, \textbf{eosType} must be set to '\texttt{IDEALGAS}'.
- For the ocean, two forms of the equation of state are available:
- linear (set \textbf{eosType} to '\texttt{LINEAR}') and a polynomial
- approximation to the full nonlinear equation ( set
- \textbf{eosType}\textit{\ }to '\texttt{POLYNOMIAL}'). In the linear
- case, you need to specify the thermal and haline expansion
- coefficients represented by the variables \textbf{tAlpha}\textit{\
-   }(in K$^{-1}$) and \textbf{sBeta} (in ppt$^{-1}$). For the nonlinear
- case, you need to generate a file of polynomial coefficients called
- \textit{POLY3.COEFFS}. To do this, use the program
- \textit{utils/knudsen2/knudsen2.f} under the model tree (a Makefile is
- available in the same directory and you will need to edit the number
- and the values of the vertical levels in \textit{knudsen2.f} so that
- they match those of your configuration).
- There there are also higher polynomials for the equation of state:
- \begin{description}
- \item['\texttt{UNESCO}':] The UNESCO equation of state formula of
-   Fofonoff and Millard \cite{fofonoff83}. This equation of state
-   assumes in-situ temperature, which is not a model variable; \emph{its use
-   is therefore discouraged, and it is only listed for completeness}.
- \item['\texttt{JMD95Z}':] A modified UNESCO formula by Jackett and
-   McDougall \cite{jackett95}, which uses the model variable potential
-   temperature as input. The '\texttt{Z}' indicates that this equation
-   of state uses a horizontally and temporally constant pressure
-   $p_{0}=-g\rho_{0}z$.
- \item['\texttt{JMD95P}':] A modified UNESCO formula by Jackett and
-   McDougall \cite{jackett95}, which uses the model variable potential
-   temperature as input. The '\texttt{P}' indicates that this equation
-   of state uses the actual hydrostatic pressure of the last time
-   step. Lagging the pressure in this way requires an additional pickup
-   file for restarts.
- \item['\texttt{MDJWF}':] The new, more accurate and less expensive
-   equation of state by McDougall et~al. \cite{mcdougall03}. It also
-   requires lagging the pressure and therefore an additional pickup
-   file for restarts.
- \end{description}
- For none of these options an reference profile of temperature or
- salinity is required.
- \subsection{Momentum equations}
- In this section, we only focus for now on the parameters that you are likely
- to change, i.e. the ones relative to forcing and dissipation for example.
- The details relevant to the vector-invariant form of the equations and the
- various advection schemes are not covered for the moment. We assume that you
- use the standard form of the momentum equations (i.e. the flux-form) with
- the default advection scheme. Also, there are a few logical variables that
- allow you to turn on/off various terms in the momentum equation. These
- variables are called \textbf{momViscosity, momAdvection, momForcing,
- useCoriolis, momPressureForcing, momStepping}\textit{, }and \textit{\ }%
- \textbf{metricTerms }and are assumed to be set to '.\texttt{TRUE}.' here.
- Look at the file \textit{model/inc/PARAMS.h }for a precise definition of
- these variables.
- \begin{itemize}
- \item initialization
- \end{itemize}
- The velocity components are initialized to 0 unless the simulation is
- starting from a pickup file (see section on simulation control parameters).
- \begin{itemize}
- \item forcing
- \end{itemize}
- This section only applies to the ocean. You need to generate wind-stress
- data into two files \textbf{zonalWindFile}\textit{\ }and \textbf{%
- meridWindFile }corresponding to the zonal and meridional components of the
- wind stress, respectively (if you want the stress to be along the direction
- of only one of the model horizontal axes, you only need to generate one
- file). The format of the files is similar to the bathymetry file. The zonal
- (meridional) stress data are assumed to be in Pa and located at U-points
- (V-points). As for the bathymetry, the precision with which to read the
- binary data is controlled by the variable \textbf{readBinaryPrec}.\textbf{\ }
- See the matlab program \textit{gendata.m }in the \textit{input }directories
- under \textit{verification }to see how simple analytical wind forcing data
- are generated for the case study experiments.
- There is also the possibility of prescribing time-dependent periodic
- forcing. To do this, concatenate the successive time records into a single
- file (for each stress component) ordered in a (x, y, t) fashion and set the
- following variables: \textbf{periodicExternalForcing }to '.\texttt{TRUE}.',
- \textbf{externForcingPeriod }to the period (in s) of which the forcing
- varies (typically 1 month), and \textbf{externForcingCycle }to the repeat
- time (in s) of the forcing (typically 1 year -- note: \textbf{%
- externForcingCycle }must be a multiple of \textbf{externForcingPeriod}).
- With these variables set up, the model will interpolate the forcing linearly
- at each iteration.
- \begin{itemize}
- \item dissipation
- \end{itemize}
- The lateral eddy viscosity coefficient is specified through the variable
- \textbf{viscAh}\textit{\ }(in m$^{2}$s$^{-1}$). The vertical eddy viscosity
- coefficient is specified through the variable \textbf{viscAz }(in m$^{2}$s$%
- ^{-1}$) for the ocean and \textbf{viscAp}\textit{\ }(in Pa$^{2}$s$^{-1}$)
- for the atmosphere. The vertical diffusive fluxes can be computed implicitly
- by setting the logical variable \textbf{implicitViscosity }to '.\texttt{TRUE}%
- .'. In addition, biharmonic mixing can be added as well through the variable
- \textbf{viscA4}\textit{\ }(in m$^{4}$s$^{-1}$). On a spherical polar grid,
- you might also need to set the variable \textbf{cosPower} which is set to 0
- by default and which represents the power of cosine of latitude to multiply
- viscosity. Slip or no-slip conditions at lateral and bottom boundaries are
- specified through the logical variables \textbf{no\_slip\_sides}\textit{\ }%
- and \textbf{no\_slip\_bottom}. If set to '\texttt{.FALSE.}', free-slip
- boundary conditions are applied. If no-slip boundary conditions are applied
- at the bottom, a bottom drag can be applied as well. Two forms are
- available: linear (set the variable \textbf{bottomDragLinear}\textit{\ }in s$%
- ^{-1}$) and quadratic (set the variable \textbf{bottomDragQuadratic}\textit{%
- \ }in m$^{-1}$).
- The Fourier and Shapiro filters are described elsewhere.
- \begin{itemize}
- \item C-D scheme
- \end{itemize}
- If you run at a sufficiently coarse resolution, you will need the C-D scheme
- for the computation of the Coriolis terms. The variable\textbf{\ tauCD},
- which represents the C-D scheme coupling timescale (in s) needs to be set.
- \begin{itemize}
- \item calculation of pressure/geopotential
- \end{itemize}
- First, to run a non-hydrostatic ocean simulation, set the logical variable
- \textbf{nonHydrostatic} to '.\texttt{TRUE}.'. The pressure field is then
- inverted through a 3D elliptic equation. (Note: this capability is not
- available for the atmosphere yet.) By default, a hydrostatic simulation is
- assumed and a 2D elliptic equation is used to invert the pressure field. The
- parameters controlling the behaviour of the elliptic solvers are the
- variables \textbf{cg2dMaxIters}\textit{\ }and \textbf{cg2dTargetResidual }%
- for the 2D case and \textbf{cg3dMaxIters}\textit{\ }and \textbf{%
- cg3dTargetResidual }for the 3D case. You probably won't need to alter the
- default values (are we sure of this?).
- For the calculation of the surface pressure (for the ocean) or surface
- geopotential (for the atmosphere) you need to set the logical variables
- \textbf{rigidLid} and \textbf{implicitFreeSurface}\textit{\ }(set one to '.%
- \texttt{TRUE}.' and the other to '.\texttt{FALSE}.' depending on how you
- want to deal with the ocean upper or atmosphere lower boundary).
- \subsection{Tracer equations}
- This section covers the tracer equations i.e. the potential temperature
- equation and the salinity (for the ocean) or specific humidity (for the
- atmosphere) equation. As for the momentum equations, we only describe for
- now the parameters that you are likely to change. The logical variables
- \textbf{tempDiffusion}\textit{, }\textbf{tempAdvection}\textit{, }\textbf{%
- tempForcing}\textit{,} and \textbf{tempStepping} allow you to turn on/off
- terms in the temperature equation (same thing for salinity or specific
- humidity with variables \textbf{saltDiffusion}\textit{, }\textbf{%
- saltAdvection}\textit{\ }etc). These variables are all assumed here to be
- set to '.\texttt{TRUE}.'. Look at file \textit{model/inc/PARAMS.h }for a
- precise definition.
- \begin{itemize}
- \item initialization
- \end{itemize}
- The initial tracer data can be contained in the binary files \textbf{%
- hydrogThetaFile }and \textbf{hydrogSaltFile}. These files should contain 3D
- data ordered in an (x, y, r) fashion with k=1 as the first vertical level.
- If no file names are provided, the tracers are then initialized with the
- values of \textbf{tRef }and \textbf{sRef }mentioned above (in the equation
- of state section). In this case, the initial tracer data are uniform in x
- and y for each depth level.
- \begin{itemize}
- \item forcing
- \end{itemize}
- This part is more relevant for the ocean, the procedure for the atmosphere
- not being completely stabilized at the moment.
- A combination of fluxes data and relaxation terms can be used for driving
- the tracer equations. \ For potential temperature, heat flux data (in W/m$%
- ^{2}$) can be stored in the 2D binary file \textbf{surfQfile}\textit{. }%
- Alternatively or in addition, the forcing can be specified through a
- relaxation term. The SST data to which the model surface temperatures are
- restored to are supposed to be stored in the 2D binary file \textbf{%
- thetaClimFile}\textit{. }The corresponding relaxation time scale coefficient
- is set through the variable \textbf{tauThetaClimRelax}\textit{\ }(in s). The
- same procedure applies for salinity with the variable names \textbf{EmPmRfile%
- }\textit{, }\textbf{saltClimFile}\textit{, }and \textbf{tauSaltClimRelax}%
- \textit{\ }for freshwater flux (in m/s) and surface salinity (in ppt) data
- files and relaxation time scale coefficient (in s), respectively. Also for
- salinity, if the CPP key \textbf{USE\_NATURAL\_BCS} is turned on, natural
- boundary conditions are applied i.e. when computing the surface salinity
- tendency, the freshwater flux is multiplied by the model surface salinity
- instead of a constant salinity value.
- As for the other input files, the precision with which to read the data is
- controlled by the variable \textbf{readBinaryPrec}. Time-dependent, periodic
- forcing can be applied as well following the same procedure used for the
- wind forcing data (see above).
- \begin{itemize}
- \item dissipation
- \end{itemize}
- Lateral eddy diffusivities for temperature and salinity/specific humidity
- are specified through the variables \textbf{diffKhT }and \textbf{diffKhS }%
- (in m$^{2}$/s). Vertical eddy diffusivities are specified through the
- variables \textbf{diffKzT }and \textbf{diffKzS }(in m$^{2}$/s) for the ocean
- and \textbf{diffKpT }and \textbf{diffKpS }(in Pa$^{2}$/s) for the
- atmosphere. The vertical diffusive fluxes can be computed implicitly by
- setting the logical variable \textbf{implicitDiffusion }to '.\texttt{TRUE}%
- .'. In addition, biharmonic diffusivities can be specified as well through
- the coefficients \textbf{diffK4T }and \textbf{diffK4S }(in m$^{4}$/s). Note
- that the cosine power scaling (specified through \textbf{cosPower }- see the
- momentum equations section) is applied to the tracer diffusivities
- (Laplacian and biharmonic) as well. The Gent and McWilliams parameterization
- for oceanic tracers is described in the package section. Finally, note that
- tracers can be also subject to Fourier and Shapiro filtering (see the
- corresponding section on these filters).
- \begin{itemize}
- \item ocean convection
- \end{itemize}
- Two options are available to parameterize ocean convection: one is to use
- the convective adjustment scheme. In this case, you need to set the variable
- \textbf{cadjFreq}, which represents the frequency (in s) with which the
- adjustment algorithm is called, to a non-zero value (if set to a negative
- value by the user, the model will set it to the tracer time step). The other
- option is to parameterize convection with implicit vertical diffusion. To do
- this, set the logical variable \textbf{implicitDiffusion }to '.\texttt{TRUE}%
- .' and the real variable \textbf{ivdc\_kappa }to a value (in m$^{2}$/s) you
- wish the tracer vertical diffusivities to have when mixing tracers
- vertically due to static instabilities. Note that \textbf{cadjFreq }and
- \textbf{ivdc\_kappa }can not both have non-zero value.
- \subsection{Simulation controls}
- The model ''clock'' is defined by the variable \textbf{deltaTClock }(in s)
- which determines the IO frequencies and is used in tagging output.
- Typically, you will set it to the tracer time step for accelerated runs
- (otherwise it is simply set to the default time step \textbf{deltaT}).
- Frequency of checkpointing and dumping of the model state are referenced to
- this clock (see below).
- \begin{itemize}
- \item run duration
- \end{itemize}
- The beginning of a simulation is set by specifying a start time (in s)
- through the real variable \textbf{startTime }or by specifying an initial
- iteration number through the integer variable \textbf{nIter0}. If these
- variables are set to nonzero values, the model will look for a ''pickup''
- file \textit{pickup.0000nIter0 }to restart the integration\textit{. }The end
- of a simulation is set through the real variable \textbf{endTime }(in s).
- Alternatively, you can specify instead the number of time steps to execute
- through the integer variable \textbf{nTimeSteps}.
- \begin{itemize}
- \item frequency of output
- \end{itemize}
- Real variables defining frequencies (in s) with which output files are
- written on disk need to be set up. \textbf{dumpFreq }controls the frequency
- with which the instantaneous state of the model is saved. \textbf{chkPtFreq }%
- and \textbf{pchkPtFreq }control the output frequency of rolling and
- permanent checkpoint files, respectively. See section 1.5.1 Output files for the
- definition of model state and checkpoint files. In addition, time-averaged
- fields can be written out by setting the variable \textbf{taveFreq} (in s).
- The precision with which to write the binary data is controlled by the
- integer variable w\textbf{riteBinaryPrec }(set it to \texttt{32} or \texttt{%
-}).
- %%% Local Variables:
- %%% mode: latex
- %%% TeX-master: t
- %%% End:

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