/[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 1.41 by jmc,
Fri Jan 22 00:38:16 2010 UTC
 Line 3
  %\section{Getting started}
- In this section, we describe how to use the model. In the first
+ We believe the best way to familiarize yourself with the
- section, we provide enough information to help you get started with
- the model. We believe the best way to familiarize yourself with the
  model is to run the case study examples provided with the base
  version. Information on how to obtain, compile, and run the code is
- found there as well as a brief description of the model structure
+ found here as well as a brief description of the model structure
- directory and the case study examples.  The latter and the code
+ directory and the case study examples. Information is also provided
- structure are described more fully in chapters
+ here on how to customize the code when you are ready to try implementing
- \ref{chap:discretization} and \ref{chap:sarch}, respectively. Here, in
+ the configuration you have in mind.  The code and algorithm
- this section, we provide information on how to customize the code when
+ are described more fully in chapters \ref{chap:discretization} and
- you are ready to try implementing the configuration you have in mind.
+ \ref{chap:sarch}.
  \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:
+ There is a web-archived support mailing list for the model that
- \begin{rawhtml} <A href=http://mitgcm.org/pelican/ target="idontexist"> \end{rawhtml}
- \begin{verbatim}
- http://mitgcm.org/pelican
- \end{verbatim}
- \begin{rawhtml} </A> \end{rawhtml}
- Here you will find an on-line version of this document, a
- ``browsable'' copy of the code and a searchable database of the model
- and site, as well as links for downloading the model and
- documentation, to data-sources, and other related sites.
- There is also a web-archived support mailing list for the model that
  you can email at \texttt{MITgcm-support@mitgcm.org} or browse at:
  \begin{rawhtml} <A href=http://mitgcm.org/mailman/listinfo/mitgcm-support/ target="idontexist"> \end{rawhtml}
  \begin{verbatim}
-Line 37 
 http://mitgcm.org/mailman/listinfo/mitgc
+Line 27 
 http://mitgcm.org/mailman/listinfo/mitgc
  http://mitgcm.org/pipermail/mitgcm-support/
  \end{verbatim}
  \begin{rawhtml} </A> \end{rawhtml}
- Essentially all of the MITgcm web pages can be searched using a
- popular web crawler such as Google or through our own search facility:
- \begin{rawhtml} <A href=http://mitgcm.org/mailman/htdig/ target="idontexist"> \end{rawhtml}
- \begin{verbatim}
- http://mitgcm.org/htdig/
- \end{verbatim}
- \begin{rawhtml} </A> \end{rawhtml}
- %%% http://www.google.com/search?q=hydrostatic+site%3Amitgcm.org
  \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 62 
 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 89 
 be set within your shell.  For a csh or
+Line 75 
 be set within your shell.  For a csh or
  \begin{verbatim}
  % setenv CVSROOT :pserver:cvsanon@mitgcm.org:/u/gcmpack
  \end{verbatim}
- in your .cshrc or .tcshrc file.  For bash or sh shells, put:
+ in your \texttt{.cshrc} or \texttt{.tcshrc} file.  For bash or sh
+ shells, put:
  \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 102 
 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{rawhtml} <A href="http://mitgcm.org/viewvc/MITgcm/MITgcm/" 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 checkout process creates a directory called \texttt{MITgcm}. If
- the directory \textit{MITgcm} exists this command updates your code
+ the directory \texttt{MITgcm} 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
+ directory \texttt{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}!  You can also use CVS to download code
+ the files in \texttt{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/public/using_cvs.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
- \paragraph*{Conventional download method}
+ \texttt{-d DIRNAME} option.  However, the \texttt{MITgcm} directories
- \label{sect:conventionalDownload}
+ they create can be changed to a different name following the check-out:
- If you do not have CVS on your system, you can download the model as a
- tar file from the web site at:
- \begin{rawhtml} <A href=http://mitgcm.org/download target="idontexist"> \end{rawhtml}
  \begin{verbatim}
- http://mitgcm.org/download/
+    %  cvs co MITgcm_verif_basic
+    %  mv MITgcm MITgcm_verif_basic
  \end{verbatim}
- \begin{rawhtml} </A> \end{rawhtml}
- The tar file still contains CVS information which we urge you not to
- 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.
- \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 179 
 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 187 
 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 214 
 that you may only have part of a patch.
+Line 219 
 that you may only have part of a patch.
  also means we can't tell what version of the code you are working
  with. So please be sure you understand what you're doing.
+ \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
+ tar file from the web site at:
+ \begin{rawhtml} <A href=http://mitgcm.org/download/ target="idontexist"> \end{rawhtml}
+ \begin{verbatim}
+ http://mitgcm.org/download/
+ \end{verbatim}
+ \begin{rawhtml} </A> \end{rawhtml}
+ The tar file still contains CVS information which we urge you not to
+ 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
+ \begin{rawhtml} <A href="mailto:MITgcm-support@mitgcm.org"> \end{rawhtml}
+ MITgcm-support@mitgcm.org
+ \begin{rawhtml} </A> \end{rawhtml}
+ mailing list.
  \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 222 
 framework for grid-point models. MITgcmU
+Line 250 
 framework for grid-point models. MITgcmU
  model that uses the framework. Under this structure the model is split
  into execution environment support code and conventional numerical
  model code. The execution environment support code is held under the
- \textit{eesupp} directory. The grid point model code is held under the
+ \texttt{eesupp} directory. The grid point model code is held under the
- \textit{model} directory. Code execution actually starts in the
+ \texttt{model} directory. Code execution actually starts in the
- \textit{eesupp} routines and not in the \textit{model} routines. For
+ \texttt{eesupp} routines and not in the \texttt{model} routines. For
- this reason the top-level
+ this reason the top-level \texttt{MAIN.F} is in the
- \textit{MAIN.F} is in the \textit{eesupp/src} directory. In general,
+ \texttt{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 \texttt{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{diags}: contains the code relative to time-averaged
- diagnostics. It is subdivided into two subdirectories \textit{inc} and
- \textit{src} that contain include files (*.\textit{h} files) and Fortran
- subroutines (*.\textit{F} files), respectively.
- \item \textit{doc}: contains brief documentation notes.
- \item \textit{eesupp}: contains the execution environment source code. 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{model}: this directory contains the main source code. Also
- subdivided into two subdirectories \textit{inc} and \textit{src}.
- \item \textit{pkg}: contains the source code for the packages. Each package
- corresponds to a subdirectory. For example, \textit{gmredi} contains the
- code related to the Gent-McWilliams/Redi scheme, \textit{aim} the code
- relative to the atmospheric intermediate physics. The packages are described
- in detail in section 3.
- \item \textit{tools}: this directory contains various useful tools. For
- example, \textit{genmake2} is a script written in csh (C-shell) 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
- compute coefficients of the polynomial approximation to the knudsen
- formula for an ocean nonlinear equation of state. The \textit{matlab}
- subdirectory contains matlab scripts for reading model output directly
- into matlab. \textit{scripts} contains C-shell 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}.
- \end{itemize}
- \section{Example experiments}
- \label{sect:modelExamples}
- %% a set of twenty-four pre-configured numerical experiments
- The MITgcm distribution comes with more than a dozen pre-configured
- numerical experiments. Some of these example experiments are tests of
- individual parts of the model code, but many are fully fledged
- numerical simulations. A few of the examples are used for tutorial
- documentation in sections \ref{sect:eg-baro} - \ref{sect:eg-global}.
- The other examples follow the same general structure as the tutorial
- examples. However, they only include brief instructions in a text file
- called {\it README}.  The examples are located in subdirectories under
- the directory \textit{verification}. Each example is briefly described
- 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}.
- \item \textit{exp1} - Four layer, ocean double gyre. This experiment
-   is described in detail in section \ref{sect:eg-baroc}.
- \item \textit{exp2} - 4x4 degree global ocean simulation with steady
-   climatological forcing. This experiment is described in detail in
-   section \ref{sect:eg-global}.
- \item \textit{exp4} - Flow over a Gaussian bump in open-water or
-   channel with open boundaries.
- \item \textit{exp5} - Inhomogenously forced ocean convection in a
-   doubly periodic box.
- \item \textit{front\_relax} - Relaxation of an ocean thermal front (test for
- Gent/McWilliams scheme). 2D (Y-Z).
- \item \textit{internal wave} - Ocean internal wave forced by open
-   boundary conditions.
- \item \textit{natl\_box} - Eastern subtropical North Atlantic with KPP
-   scheme; 1 month integration
- \item \textit{hs94.1x64x5} - Zonal averaged atmosphere using Held and
-   Suarez '94 forcing.
- \item \textit{hs94.128x64x5} - 3D atmosphere dynamics using Held and
-   Suarez '94 forcing.
- \item \textit{hs94.cs-32x32x5} - 3D atmosphere dynamics using Held and
-   Suarez '94 forcing on the cubed sphere.
- \item \textit{aim.5l\_zon-ave} - Intermediate Atmospheric physics.
-   Global Zonal Mean configuration, 1x64x5 resolution.
- \item \textit{aim.5l\_XZ\_Equatorial\_Slice} - Intermediate
-   Atmospheric physics, equatorial Slice configuration.  2D (X-Z).
- \item \textit{aim.5l\_Equatorial\_Channel} - Intermediate Atmospheric
-   physics. 3D Equatorial Channel configuration.
- \item \textit{aim.5l\_LatLon} - Intermediate Atmospheric physics.
-   Global configuration, on latitude longitude grid with 128x64x5 grid
-   points ($2.8^\circ{\rm degree}$ resolution).
- \item \textit{adjustment.128x64x1} Barotropic adjustment problem on
-   latitude longitude grid with 128x64 grid points ($2.8^\circ{\rm
-     degree}$ resolution).
- \item \textit{adjustment.cs-32x32x1} Barotropic adjustment problem on
-   cube sphere grid with 32x32 points per face ( roughly $2.8^\circ{\rm
-     degree}$ resolution).
- \item \textit{advect\_cs} Two-dimensional passive advection test on
-   cube sphere grid.
- \item \textit{advect\_xy} Two-dimensional (horizontal plane) passive
-   advection test on Cartesian grid.
- \item \textit{advect\_yz} Two-dimensional (vertical plane) passive
-   advection test on Cartesian grid.
- \item \textit{carbon} Simple passive tracer experiment. Includes
-   derivative calculation. Described in detail in section
-   \ref{sect:eg-carbon-ad}.
- \item \textit{flt\_example} Example of using float package.
- \item \textit{global\_ocean.90x40x15} Global circulation with GM, flux
-   boundary conditions and poles.
- \item \textit{global\_ocean\_pressure} Global circulation in pressure
-   coordinate (non-Boussinesq ocean model). Described in detail in
-   section \ref{sect:eg-globalpressure}.
- \item \textit{solid-body.cs-32x32x1} Solid body rotation test for cube
-   sphere grid.
- \end{enumerate}
- \subsection{Directory structure of model examples}
- Each example directory has the following subdirectories:
  \begin{itemize}
- \item \textit{code}: contains the code particular to the example. At a
-   minimum, this directory includes the following files:
-   \begin{itemize}
+ \item \texttt{doc}: contains brief documentation notes.
-   \item \textit{code/CPP\_EEOPTIONS.h}: declares CPP keys relative to
-     the ``execution environment'' part of the code. The default
+ \item \texttt{eesupp}: contains the execution environment source code.
-     version is located in \textit{eesupp/inc}.
+   Also subdivided into two subdirectories \texttt{inc} and
+   \texttt{src}.
-   \item \textit{code/CPP\_OPTIONS.h}: declares CPP keys relative to
-     the ``numerical model'' part of the code. The default version is
+ \item \texttt{model}: this directory contains the main source code.
-     located in \textit{model/inc}.
+   Also subdivided into two subdirectories \texttt{inc} and
+   \texttt{src}.
-   \item \textit{code/SIZE.h}: declares size of underlying
-     computational grid.  The default version is located in
+ \item \texttt{pkg}: contains the source code for the packages. Each
-     \textit{model/inc}.
+   package corresponds to a subdirectory. For example, \texttt{gmredi}
-   \end{itemize}
+   contains the code related to the Gent-McWilliams/Redi scheme,
+   \texttt{aim} the code relative to the atmospheric intermediate
+   physics. The packages are described in detail in chapter \ref{chap.packagesI}.
+ \item \texttt{tools}: this directory contains various useful tools.
+   For example, \texttt{genmake2} is a script written in csh (C-shell)
+   that should be used to generate your makefile. The directory
+   \texttt{adjoint} contains the makefile specific to the Tangent
+   linear and Adjoint Compiler (TAMC) that generates the adjoint code.
+   The latter is described in detail in part \ref{chap.ecco}.
+   This directory also contains the subdirectory build\_options, which
+   contains the `optfiles' with the compiler options for the different
+   compilers and machines that can run MITgcm.
+ \item \texttt{utils}: this directory contains various utilities. The
+   subdirectory \texttt{knudsen2} contains code and a makefile that
+   compute coefficients of the polynomial approximation to the knudsen
+   formula for an ocean nonlinear equation of state. The
+   \texttt{matlab} subdirectory contains matlab scripts for reading
+   model output directly into matlab. \texttt{scripts} contains C-shell
+   post-processing scripts for joining processor-based and tiled-based
+   model output. The subdirectory exch2 contains the code needed for
+   the exch2 package to work with different combinations of domain
+   decompositions.
+ \item \texttt{verification}: this directory contains the model
+   examples. See section \ref{sect:modelExamples}.
+ \item \texttt{jobs}: contains sample job scripts for running MITgcm.
-   In addition, other include files and subroutines might be present in
+ \item \texttt{lsopt}: Line search code used for optimization.
-   \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 minimum, the \textit{input} directory contains the
-   following files:
-   \begin{itemize}
-   \item \textit{input/data}: this file, written as a namelist,
-     specifies the main parameters for the experiment.
-   \item \textit{input/data.pkg}: contains parameters relative to the
+ \item \texttt{optim}: Interface between MITgcm and line search code.
-     packages used in the experiment.
-   \item \textit{input/eedata}: this file contains ``execution
-     environment'' data. At present, this consists of a specification
-     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
- topography files as well as the files describing the initial state of
- the experiment.  This varies from experiment to experiment. See
- 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
-   useful for comparison with your own output when you run the
-   experiment.
  \end{itemize}
- Once you have chosen the example you want to run, you are ready to compile
+ \section[Building MITgcm]{Building the code}
- the code.
- \section{Building the code}
  \label{sect:buildingCode}
+ \begin{rawhtml}
- To compile the code, we use the {\em make} program. This uses a file
+ <!-- CMIREDIR:buildingCode: -->
- ({\em Makefile}) that allows us to pre-process source files, specify
+ \end{rawhtml}
- compiler and optimization options and also figures out any file
- dependencies. We supply a script ({\em genmake2}), described in
+ To compile the code, we use the \texttt{make} program. This uses a
- section \ref{sect:genmake}, that automatically creates the {\em
+ file (\texttt{Makefile}) that allows us to pre-process source files,
-   Makefile} for you. You then need to build the dependencies and
+ specify compiler and optimization options and also figures out any
+ file dependencies. We supply a script (\texttt{genmake2}), described
+ in section \ref{sect:genmake}, that automatically creates the
+ \texttt{Makefile} for you. You then need to build the dependencies and
  compile the code.
- As an example, let's assume that you want to build and run experiment
+ As an example, assume that you want to build and run experiment
- \textit{verification/exp2}. The are multiple ways and places to
+ \texttt{verification/exp2}. The are multiple ways and places to
  actually do this but here let's build the code in
- \textit{verification/exp2/input}:
+ \texttt{verification/exp2/build}:
  \begin{verbatim}
- % cd verification/exp2/input
+ % cd verification/exp2/build
  \end{verbatim}
- First, build the {\em Makefile}:
+ First, build the \texttt{Makefile}:
  \begin{verbatim}
  % ../../../tools/genmake2 -mods=../code
  \end{verbatim}
- The command line option tells {\em genmake} to override model source
+ The command line option tells \texttt{genmake} to override model source
- code with any files in the directory {\em ./code/}.
+ code with any files in the directory \texttt{../code/}.
- On many systems, the {\em genmake2} program will be able to
+ On many systems, the \texttt{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
+ within the user's path (``\texttt{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 \texttt{tools/build\_options} directory.  Under some
- may have to create a new ``optfile'' in order to specify the exact
+ circumstances, a user may have to create a new ``optfile'' in order to
- combination of compiler, compiler flags, libraries, and other options
+ specify the exact combination of compiler, compiler flags, libraries,
- necessary to build a particular configuration of MITgcm.  In such
+ and other options necessary to build a particular configuration of
- cases, it is generally helpful to read the existing ``optfiles'' and
+ MITgcm.  In such cases, it is generally helpful to read the existing
- mimic their syntax.
+ ``optfiles'' 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:
+ To specify an optfile to \texttt{genmake2}, the syntax is:
  \begin{verbatim}
  % ../../../tools/genmake2 -mods=../code -of /path/to/optfile
  \end{verbatim}
- Once a {\em Makefile} has been generated, we create the dependencies:
+ Once a \texttt{Makefile} has been generated, we create the
+ dependencies with the command:
  \begin{verbatim}
  % make depend
  \end{verbatim}
- This modifies the {\em Makefile} by attaching a [long] list of files
+ This modifies the \texttt{Makefile} by attaching a (usually, long)
- upon which other files depend. The purpose of this is to reduce
+ list of files upon which other files depend. The purpose of this is to
- re-compilation if and when you start to modify the code. The {\tt make
+ reduce re-compilation if and when you start to modify the code. The
-   depend} command also creates links from the model source to this
+ {\tt make depend} command also creates links from the model source to
- directory.
+ this 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:
+ Next one can compile the code using:
  \begin{verbatim}
  % make
  \end{verbatim}
- The {\tt make} command creates an executable called \textit{mitgcmuv}.
+ The {\tt make} command creates an executable called \texttt{mitgcmuv}.
  Additional make ``targets'' are defined within the makefile to aid in
- the production of adjoint and other versions of MITgcm.
+ the production of adjoint and other versions of MITgcm.  On SMP
+ (shared multi-processor) systems, the build process can often be sped
+ up appreciably using the command:
+ \begin{verbatim}
+ % make -j 2
+ \end{verbatim}
+ where the ``2'' can be replaced with a number that corresponds to the
+ number of CPUs available.
  Now you are ready to run the model. General instructions for doing so are
- given in section \ref{sect:runModel}. Here, we can run the model with:
+ given in section \ref{sect:runModel}. Here, we can run the model by
+ first creating links to all the input files:
+ \begin{verbatim}
+ ln -s ../input/* .
+ \end{verbatim}
+ and then calling the executable with:
  \begin{verbatim}
  ./mitgcmuv > output.txt
  \end{verbatim}
- where we are re-directing the stream of text output to the file {\em
+ where we are re-directing the stream of text output to the file
- output.txt}.
+ \texttt{output.txt}.
  \subsection{Building/compiling the code elsewhere}
-Line 613 
 the one experiment:
+Line 513 
 the one experiment:
  \end{verbatim}
+ \subsection{Using \texttt{genmake2}}
- \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.
+ in the \texttt{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
+ relies upon a number of ``optfiles'' located in the
-   tools/build\_options} directory.
+ \texttt{tools/build\_options} directory.
  The purpose of the optfiles is to provide all the compilation options
  for particular ``platforms'' (where ``platform'' roughly means the
-Line 707 
 obtained from:
+Line 606 
 obtained from:
  The most important command-line options are:
  \begin{description}
- \item[--optfile=/PATH/FILENAME] specifies the optfile that should be
+ \item[\texttt{--optfile=/PATH/FILENAME}] specifies the optfile that
-   used for a particular build.
+   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
-Line 719 
 The most important command-line options
+Line 618 
 The most important command-line options
    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
+ \item[\texttt{--pdefault='PKG1 PKG2 PKG3 ...'}] specifies the default
-   packages.
+   set of packages to be used.  The normal order of precedence for
+   packages is as follows:
+   \begin{enumerate}
+   \item If available, the command line (\texttt{--pdefault}) settings
+     over-rule any others.
+   \item Next, \texttt{genmake2} will look for a file named
+     ``\texttt{packages.conf}'' in the local directory or in any of the
+     directories specified with the \texttt{--mods} option.
+   \item Finally, if neither of the above are available,
+     \texttt{genmake2} will use the \texttt{/pkg/pkg\_default} file.
+   \end{enumerate}
+ \item[\texttt{--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
-Line 731 
 The most important command-line options
+Line 645 
 The most important command-line options
    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
+ \item[\texttt{--adof=/path/to/file}] specifies the "adjoint" or
-   packages to be used.
+   automatic differentiation options file to be used.  The file is
+   analogous to the ``optfile'' defined above but it specifies
-   If not set, the default package list will be read from {\em
+   information for the AD build process.
-     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"
-Line 749 
 The most important command-line options
+Line 657 
 The most important command-line options
    "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
+ \item[\texttt{--mods='DIR1 DIR2 DIR3 ...'}] specifies a list of
-   containing ``modifications''.  These directories contain files with
+   directories containing ``modifications''.  These directories contain
-   names that may (or may not) exist in the main MITgcm source tree but
+   files with names that may (or may not) exist in the main MITgcm
-   will be overridden by any identically-named sources within the
+   source tree but will be overridden by any identically-named sources
-   ``MODS'' directories.
+   within the ``MODS'' directories.
    The order of precedence for this "name-hiding" is as follows:
    \begin{itemize}
-Line 766 
 The most important command-line options
+Line 674 
 The most important command-line options
      ``-standarddirs'' option)
    \end{itemize}
- \item[--make=/path/to/gmake] Due to the poor handling of soft-links and
+ \item[\texttt{--mpi}] This option enables certain MPI features (using
-   other bugs common with the \texttt{make} versions provided by
+   CPP \texttt{\#define}s) within the code and is necessary for MPI
-   commercial Unix vendors, GNU \texttt{make} (sometimes called
+   builds (see Section \ref{sect:mpi-build}).
-   \texttt{gmake}) should be preferred.  This option provides a means
-   for specifying the make executable to be used.
+ \item[\texttt{--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.
+ \item[\texttt{--bash=/path/to/sh}] On some (usually older UNIX)
+   machines, the ``bash'' shell is unavailable.  To run on these
+   systems, \texttt{genmake2} can be invoked using an ``sh'' (that is,
+   a Bourne, POSIX, or compatible) shell.  The syntax in these
+   circumstances is:
+   \begin{center}
+     \texttt{\%  /bin/sh genmake2 -bash=/bin/sh [...options...]}
+   \end{center}
+   where \texttt{/bin/sh} can be replaced with the full path and name
+   of the desired shell.
  \end{description}
+ \subsection{Building with MPI}
+ \label{sect:mpi-build}
- \section{Running the model}
+ Building MITgcm to use MPI libraries can be complicated due to the
- \label{sect:runModel}
+ variety of different MPI implementations available, their dependencies
+ or interactions with different compilers, and their often ad-hoc
+ locations within file systems.  For these reasons, its generally a
+ good idea to start by finding and reading the documentation for your
+ machine(s) and, if necessary, seeking help from your local systems
+ administrator.
+ The steps for building MITgcm with MPI support are:
+ \begin{enumerate}
+ \item Determine the locations of your MPI-enabled compiler and/or MPI
+   libraries and put them into an options file as described in Section
+   \ref{sect:genmake}.  One can start with one of the examples in:
+   \begin{rawhtml} <A
+     href="http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/build_options/">
+   \end{rawhtml}
+   \begin{center}
+     \texttt{MITgcm/tools/build\_options/}
+   \end{center}
+   \begin{rawhtml} </A> \end{rawhtml}
+   such as \texttt{linux\_ia32\_g77+mpi\_cg01} or
+   \texttt{linux\_ia64\_efc+mpi} and then edit it to suit the machine at
+   hand.  You may need help from your user guide or local systems
+   administrator to determine the exact location of the MPI libraries.
+   If libraries are not installed, MPI implementations and related
+   tools are available including:
+   \begin{itemize}
+   \item \begin{rawhtml} <A
+       href="http://www-unix.mcs.anl.gov/mpi/mpich/">
+     \end{rawhtml}
+     MPICH
+     \begin{rawhtml} </A> \end{rawhtml}
+   \item \begin{rawhtml} <A
+       href="http://www.lam-mpi.org/">
+     \end{rawhtml}
+     LAM/MPI
+     \begin{rawhtml} </A> \end{rawhtml}
+   \item \begin{rawhtml} <A
+       href="http://www.osc.edu/~pw/mpiexec/">
+     \end{rawhtml}
+     MPIexec
+     \begin{rawhtml} </A> \end{rawhtml}
+   \end{itemize}
+ \item Build the code with the \texttt{genmake2} \texttt{-mpi} option
+   (see Section \ref{sect:genmake}) using commands such as:
+ {\footnotesize \begin{verbatim}
+   %  ../../../tools/genmake2 -mods=../code -mpi -of=YOUR_OPTFILE
+   %  make depend
+   %  make
+ \end{verbatim} }
+ \item Run the code with the appropriate MPI ``run'' or ``exec''
+   program provided with your particular implementation of MPI.
+   Typical MPI packages such as MPICH will use something like:
+ \begin{verbatim}
+   %  mpirun -np 4 -machinefile mf ./mitgcmuv
+ \end{verbatim}
+   Sightly more complicated scripts may be needed for many machines
+   since execution of the code may be controlled by both the MPI
+   library and a job scheduling and queueing system such as PBS,
+   LoadLeveller, Condor, or any of a number of similar tools.  A few
+   example scripts (those used for our \begin{rawhtml} <A
+     href="http://mitgcm.org/public/testing.html"> \end{rawhtml}regular
+   verification runs\begin{rawhtml} </A> \end{rawhtml}) are available
+   at:
+   \begin{rawhtml} <A
+     href="http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/example_scripts/">
+   \end{rawhtml}
+   {\footnotesize \tt
+     http://mitgcm.org/viewvc/MITgcm/MITgcm/tools/example\_scripts/ }
+   \begin{rawhtml} </A> \end{rawhtml}
+   or at:
+   \begin{rawhtml} <A
+     href="http://mitgcm.org/viewvc/MITgcm/MITgcm_contrib/test_scripts/">
+   \end{rawhtml}
+   {\footnotesize \tt
+     http://mitgcm.org/viewvc/MITgcm/MITgcm\_contrib/test\_scripts/ }
+   \begin{rawhtml} </A> \end{rawhtml}
- If compilation finished succesfuully (section \ref{sect:buildModel})
+ \end{enumerate}
- then an executable called {\em mitgcmuv} will now exist in the local
- directory.
- To run the model as a single process (ie. not in parallel) simply
+ An example of the above process on the MITgcm cluster (``cg01'') using
- type:
+ the GNU g77 compiler and the mpich MPI library is:
+ {\footnotesize \begin{verbatim}
+   %  cd MITgcm/verification/exp5
+   %  mkdir build
+   %  cd build
+   %  ../../../tools/genmake2 -mpi -mods=../code \
+        -of=../../../tools/build_options/linux_ia32_g77+mpi_cg01
+   %  make depend
+   %  make
+   %  cd ../input
+   %  /usr/local/pkg/mpi/mpi-1.2.4..8a-gm-1.5/g77/bin/mpirun.ch_gm \
+        -machinefile mf --gm-kill 5 -v -np 2  ../build/mitgcmuv
+ \end{verbatim} }
+ \section[Running MITgcm]{Running the model in prognostic mode}
+ \label{sect:runModel}
+ \begin{rawhtml}
+ <!-- CMIREDIR:runModel: -->
+ \end{rawhtml}
+ If compilation finished succesfully (section \ref{sect:buildingCode})
+ then an executable called \texttt{mitgcmuv} will now exist in the
+ local directory.
+ To run the model as a single process (\textit{ie.} not in parallel)
+ simply type:
  \begin{verbatim}
  % ./mitgcmuv
  \end{verbatim}
-Line 794 
 do!). The above command will spew out ma
+Line 823 
 do!). The above command will spew out ma
  your screen.  This output contains details such as parameter values as
  well as diagnostics such as mean Kinetic energy, largest CFL number,
  etc. It is worth keeping this text output with the binary output so we
- normally re-direct the {\em stdout} stream as follows:
+ normally re-direct the \texttt{stdout} stream as follows:
  \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 \texttt{verification}, an example of the
+ output is kept in \texttt{results/output.txt} for comparison. You can
+ compare your \texttt{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 and, when using \texttt{mnc},
- ``state'' of the model is written out, which is made of the following files:
+ sometimes even directories.  Depending upon the I/O package(s)
+ selected at compile time (either \texttt{mdsio} or \texttt{mnc} or
+ both as determined by \texttt{code/packages.conf}) and the run-time
+ flags set (in \texttt{input/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 $>
+ \item \texttt{U.00000nIter} - zonal component of velocity field (m/s
-$ eastward).
+   and positive eastward).
- \item \textit{V.00000nIter} - meridional component of velocity field (m/s
+ \item \texttt{V.00000nIter} - meridional component of velocity field
- and $> 0$ northward).
+   (m/s and positive northward).
- \item \textit{W.00000nIter} - vertical component of velocity field (ocean:
+ \item \texttt{W.00000nIter} - vertical component of velocity field
- m/s and $> 0$ upward, atmosphere: Pa/s and $> 0$ towards increasing pressure
+   (ocean: m/s and positive upward, atmosphere: Pa/s and positive
- i.e. downward).
+   towards increasing pressure i.e. downward).
- \item \textit{T.00000nIter} - potential temperature (ocean: $^{0}$C,
+ \item \texttt{T.00000nIter} - potential temperature (ocean:
- atmosphere: $^{0}$K).
+   $^{\circ}\mathrm{C}$, atmosphere: $^{\circ}\mathrm{K}$).
- \item \textit{S.00000nIter} - ocean: salinity (psu), atmosphere: water vapor
+ \item \texttt{S.00000nIter} - ocean: salinity (psu), atmosphere: water
- (g/kg).
+   vapor (g/kg).
- \item \textit{Eta.00000nIter} - ocean: surface elevation (m), atmosphere:
+ \item \texttt{Eta.00000nIter} - ocean: surface elevation (m),
- surface pressure anomaly (Pa).
+   atmosphere: surface pressure anomaly (Pa).
  \end{itemize}
- The chain \textit{00000nIter} consists of ten figures that specify the
+ The chain \texttt{00000nIter} consists of ten figures that specify the
- iteration number at which the output is written out. For example, \textit{%
+ iteration number at which the output is written out. For example,
- U.0000000300} is the zonal velocity at iteration 300.
+ \texttt{U.0000000300} is the zonal velocity at iteration 300.
  In addition, a ``pickup'' or ``checkpoint'' file called:
  \begin{itemize}
- \item \textit{pickup.00000nIter}
+ \item \texttt{pickup.00000nIter}
  \end{itemize}
  is written out. This file represents the state of the model in a condensed
-Line 846 
 form and is used for restarting the inte
+Line 890 
 form and is used for restarting the inte
  there is an additional ``pickup'' file:
  \begin{itemize}
- \item \textit{pickup\_cd.00000nIter}
+ \item \texttt{pickup\_cd.00000nIter}
  \end{itemize}
  containing the D-grid velocity data and that has to be written out as well
  in order to restart the integration. Rolling checkpoint files are the same
  as the pickup files but are named differently. Their name contain the chain
- \textit{ckptA} or \textit{ckptB} instead of \textit{00000nIter}. They can be
+ \texttt{ckptA} or \texttt{ckptB} instead of \texttt{00000nIter}. They can be
  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}}.
  \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 \texttt{.data} and \texttt{.meta}. The
- binary form (big\_endian by default). The \textit{.meta} file is a
+ \texttt{.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 \texttt{.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
+ \texttt{.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.
+ \texttt{utils/matlab} under the root tree. The script \texttt{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 937 
 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 and
+ they are described in Section \ref{sec:pkg:mnc}.
- 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.
+ The MNC output files are all in the ``self-describing'' netCDF
+ format and can thus be browsed and/or plotted using tools such as:
  \begin{itemize}
- \item initialization
+ \item \texttt{ncdump} is a utility which is typically included
- \end{itemize}
+   with every netCDF install:
+   \begin{rawhtml} <A href="http://www.unidata.ucar.edu/packages/netcdf/"> \end{rawhtml}
- The velocity components are initialized to 0 unless the simulation is
+ \begin{verbatim}
- starting from a pickup file (see section on simulation control parameters).
+ http://www.unidata.ucar.edu/packages/netcdf/
+ \end{verbatim}
- \begin{itemize}
+   \begin{rawhtml} </A> \end{rawhtml} and it converts the netCDF
- \item forcing
+   binaries into formatted ASCII text files.
- \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 \texttt{ncview} utility is a very convenient and quick way
- \item frequency of output
+   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://mexcdf.sourceforge.net/"> \end{rawhtml}
+ \begin{verbatim}
+ http://mexcdf.sourceforge.net/
+ \end{verbatim}
+   \begin{rawhtml} </A> \end{rawhtml}
+   \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}
- 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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