| 1 | edhill | 1.24 | % $Header: /u/gcmpack/manual/part3/getting_started.tex,v 1.23 2004/04/08 02:24:23 edhill Exp $ | 
| 2 | adcroft | 1.2 | % $Name:  $ | 
| 3 | adcroft | 1.1 |  | 
| 4 | adcroft | 1.4 | %\section{Getting started} | 
| 5 | adcroft | 1.1 |  | 
| 6 | adcroft | 1.4 | In this section, we describe how to use the model. In the first | 
| 7 |  |  | section, we provide enough information to help you get started with | 
| 8 |  |  | the model. We believe the best way to familiarize yourself with the | 
| 9 |  |  | model is to run the case study examples provided with the base | 
| 10 |  |  | version. Information on how to obtain, compile, and run the code is | 
| 11 |  |  | found there as well as a brief description of the model structure | 
| 12 |  |  | directory and the case study examples.  The latter and the code | 
| 13 |  |  | structure are described more fully in chapters | 
| 14 |  |  | \ref{chap:discretization} and \ref{chap:sarch}, respectively. Here, in | 
| 15 |  |  | this section, we provide information on how to customize the code when | 
| 16 |  |  | you are ready to try implementing the configuration you have in mind. | 
| 17 |  |  |  | 
| 18 |  |  | \section{Where to find information} | 
| 19 |  |  | \label{sect:whereToFindInfo} | 
| 20 |  |  |  | 
| 21 | edhill | 1.15 | A web site is maintained for release 2 (``Pelican'') of MITgcm: | 
| 22 |  |  | \begin{rawhtml} <A href=http://mitgcm.org/pelican/ target="idontexist"> \end{rawhtml} | 
| 23 | adcroft | 1.4 | \begin{verbatim} | 
| 24 | edhill | 1.15 | http://mitgcm.org/pelican | 
| 25 | adcroft | 1.4 | \end{verbatim} | 
| 26 | edhill | 1.15 | \begin{rawhtml} </A> \end{rawhtml} | 
| 27 | adcroft | 1.4 | Here you will find an on-line version of this document, a | 
| 28 |  |  | ``browsable'' copy of the code and a searchable database of the model | 
| 29 |  |  | and site, as well as links for downloading the model and | 
| 30 | edhill | 1.15 | documentation, to data-sources, and other related sites. | 
| 31 | adcroft | 1.4 |  | 
| 32 | edhill | 1.15 | There is also a web-archived support mailing list for the model that | 
| 33 |  |  | you can email at \texttt{MITgcm-support@mitgcm.org} or browse at: | 
| 34 |  |  | \begin{rawhtml} <A href=http://mitgcm.org/mailman/listinfo/mitgcm-support/ target="idontexist"> \end{rawhtml} | 
| 35 |  |  | \begin{verbatim} | 
| 36 |  |  | http://mitgcm.org/mailman/listinfo/mitgcm-support/ | 
| 37 |  |  | http://mitgcm.org/pipermail/mitgcm-support/ | 
| 38 |  |  | \end{verbatim} | 
| 39 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 40 |  |  | Essentially all of the MITgcm web pages can be searched using a | 
| 41 |  |  | popular web crawler such as Google or through our own search facility: | 
| 42 | edhill | 1.16 | \begin{rawhtml} <A href=http://mitgcm.org/mailman/htdig/ target="idontexist"> \end{rawhtml} | 
| 43 | adcroft | 1.1 | \begin{verbatim} | 
| 44 | edhill | 1.15 | http://mitgcm.org/htdig/ | 
| 45 | adcroft | 1.1 | \end{verbatim} | 
| 46 | edhill | 1.15 | \begin{rawhtml} </A> \end{rawhtml} | 
| 47 |  |  | %%% http://www.google.com/search?q=hydrostatic+site%3Amitgcm.org | 
| 48 |  |  |  | 
| 49 |  |  |  | 
| 50 | adcroft | 1.4 |  | 
| 51 |  |  | \section{Obtaining the code} | 
| 52 |  |  | \label{sect:obtainingCode} | 
| 53 | adcroft | 1.1 |  | 
| 54 | cnh | 1.7 | MITgcm can be downloaded from our system by following | 
| 55 |  |  | the instructions below. As a courtesy we ask that you send e-mail to us at | 
| 56 | edhill | 1.14 | \begin{rawhtml} <A href=mailto:MITgcm-support@mitgcm.org> \end{rawhtml} | 
| 57 |  |  | MITgcm-support@mitgcm.org | 
| 58 | cnh | 1.7 | \begin{rawhtml} </A> \end{rawhtml} | 
| 59 |  |  | to enable us to keep track of who's using the model and in what application. | 
| 60 |  |  | You can download the model two ways: | 
| 61 |  |  |  | 
| 62 |  |  | \begin{enumerate} | 
| 63 | cnh | 1.9 | \item Using CVS software. CVS is a freely available source code management | 
| 64 | cnh | 1.7 | tool. To use CVS you need to have the software installed. Many systems | 
| 65 |  |  | come with CVS pre-installed, otherwise good places to look for | 
| 66 |  |  | the software for a particular platform are | 
| 67 |  |  | \begin{rawhtml} <A href=http://www.cvshome.org/ target="idontexist"> \end{rawhtml} | 
| 68 |  |  | cvshome.org | 
| 69 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 70 |  |  | and | 
| 71 |  |  | \begin{rawhtml} <A href=http://www.wincvs.org/ target="idontexist"> \end{rawhtml} | 
| 72 |  |  | wincvs.org | 
| 73 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 74 |  |  | . | 
| 75 |  |  |  | 
| 76 |  |  | \item Using a tar file. This method is simple and does not | 
| 77 |  |  | require any special software. However, this method does not | 
| 78 |  |  | provide easy support for maintenance updates. | 
| 79 |  |  |  | 
| 80 |  |  | \end{enumerate} | 
| 81 |  |  |  | 
| 82 | edhill | 1.19 | \subsubsection{Checkout from CVS} | 
| 83 |  |  | \label{sect:cvs_checkout} | 
| 84 |  |  |  | 
| 85 | adcroft | 1.1 | If CVS is available on your system, we strongly encourage you to use it. CVS | 
| 86 |  |  | provides an efficient and elegant way of organizing your code and keeping | 
| 87 |  |  | track of your changes. If CVS is not available on your machine, you can also | 
| 88 |  |  | download a tar file. | 
| 89 |  |  |  | 
| 90 | edhill | 1.15 | Before you can use CVS, the following environment variable(s) should | 
| 91 |  |  | be set within your shell.  For a csh or tcsh shell, put the following | 
| 92 |  |  | \begin{verbatim} | 
| 93 |  |  | % setenv CVSROOT :pserver:cvsanon@mitgcm.org:/u/gcmpack | 
| 94 |  |  | \end{verbatim} | 
| 95 |  |  | in your .cshrc or .tcshrc file.  For bash or sh shells, put: | 
| 96 | adcroft | 1.1 | \begin{verbatim} | 
| 97 | edhill | 1.15 | % export CVSROOT=':pserver:cvsanon@mitgcm.org:/u/gcmpack' | 
| 98 | adcroft | 1.6 | \end{verbatim} | 
| 99 | edhill | 1.20 | in your \texttt{.profile} or \texttt{.bashrc} file. | 
| 100 | adcroft | 1.6 |  | 
| 101 | edhill | 1.15 |  | 
| 102 |  |  | To get MITgcm through CVS, first register with the MITgcm CVS server | 
| 103 |  |  | using command: | 
| 104 | adcroft | 1.6 | \begin{verbatim} | 
| 105 | adcroft | 1.1 | % cvs login ( CVS password: cvsanon ) | 
| 106 |  |  | \end{verbatim} | 
| 107 | edhill | 1.15 | You only need to do a ``cvs login'' once. | 
| 108 | adcroft | 1.1 |  | 
| 109 | edhill | 1.15 | To obtain the latest sources type: | 
| 110 |  |  | \begin{verbatim} | 
| 111 |  |  | % cvs co MITgcm | 
| 112 |  |  | \end{verbatim} | 
| 113 |  |  | or to get a specific release type: | 
| 114 | adcroft | 1.1 | \begin{verbatim} | 
| 115 | edhill | 1.16 | % cvs co -P -r checkpoint52i_post  MITgcm | 
| 116 | adcroft | 1.1 | \end{verbatim} | 
| 117 | edhill | 1.15 | The MITgcm web site contains further directions concerning the source | 
| 118 |  |  | code and CVS.  It also contains a web interface to our CVS archive so | 
| 119 |  |  | that one may easily view the state of files, revisions, and other | 
| 120 |  |  | development milestones: | 
| 121 | edhill | 1.17 | \begin{rawhtml} <A href=''http://mitgcm.org/download'' target="idontexist"> \end{rawhtml} | 
| 122 | edhill | 1.15 | \begin{verbatim} | 
| 123 | edhill | 1.17 | http://mitgcm.org/source_code.html | 
| 124 | edhill | 1.15 | \end{verbatim} | 
| 125 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 126 | adcroft | 1.1 |  | 
| 127 | edhill | 1.19 | As a convenience, the MITgcm CVS server contains aliases which are | 
| 128 |  |  | named subsets of the codebase.  These aliases can be especially | 
| 129 |  |  | helpful when used over slow internet connections or on machines with | 
| 130 |  |  | restricted storage space.  Table \ref{tab:cvsModules} contains a list | 
| 131 |  |  | of CVS aliases | 
| 132 |  |  | \begin{table}[htb] | 
| 133 |  |  | \centering | 
| 134 |  |  | \begin{tabular}[htb]{|lp{3.25in}|}\hline | 
| 135 |  |  | \textbf{Alias Name}    &  \textbf{Information (directories) Contained}  \\\hline | 
| 136 |  |  | \texttt{MITgcm\_code}  &  Only the source code -- none of the verification examples.  \\ | 
| 137 |  |  | \texttt{MITgcm\_verif\_basic} | 
| 138 |  |  | &  Source code plus a small set of the verification examples | 
| 139 |  |  | (\texttt{global\_ocean.90x40x15}, \texttt{aim.5l\_cs}, \texttt{hs94.128x64x5}, | 
| 140 |  |  | \texttt{front\_relax}, and \texttt{plume\_on\_slope}).  \\ | 
| 141 |  |  | \texttt{MITgcm\_verif\_atmos}  &  Source code plus all of the atmospheric examples.  \\ | 
| 142 |  |  | \texttt{MITgcm\_verif\_ocean}  &  Source code plus all of the oceanic examples.  \\ | 
| 143 |  |  | \texttt{MITgcm\_verif\_all}    &  Source code plus all of the | 
| 144 |  |  | verification examples. \\\hline | 
| 145 |  |  | \end{tabular} | 
| 146 |  |  | \caption{MITgcm CVS Modules} | 
| 147 |  |  | \label{tab:cvsModules} | 
| 148 |  |  | \end{table} | 
| 149 | edhill | 1.15 |  | 
| 150 |  |  | The checkout process creates a directory called \textit{MITgcm}. If | 
| 151 |  |  | the directory \textit{MITgcm} exists this command updates your code | 
| 152 |  |  | based on the repository. Each directory in the source tree contains a | 
| 153 |  |  | directory \textit{CVS}. This information is required by CVS to keep | 
| 154 |  |  | track of your file versions with respect to the repository. Don't edit | 
| 155 |  |  | the files in \textit{CVS}!  You can also use CVS to download code | 
| 156 |  |  | updates.  More extensive information on using CVS for maintaining | 
| 157 |  |  | MITgcm code can be found | 
| 158 | edhill | 1.17 | \begin{rawhtml} <A href=''http://mitgcm.org/usingcvstoget.html'' target="idontexist"> \end{rawhtml} | 
| 159 | cnh | 1.7 | here | 
| 160 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 161 |  |  | . | 
| 162 | edhill | 1.19 | It is important to note that the CVS aliases in Table | 
| 163 |  |  | \ref{tab:cvsModules} cannot be used in conjunction with the CVS | 
| 164 |  |  | \texttt{-d DIRNAME} option.  However, the \texttt{MITgcm} directories | 
| 165 |  |  | they create can be changed to a different name following the check-out: | 
| 166 |  |  | \begin{verbatim} | 
| 167 |  |  | %  cvs co MITgcm_verif_basic | 
| 168 |  |  | %  mv MITgcm MITgcm_verif_basic | 
| 169 |  |  | \end{verbatim} | 
| 170 | cnh | 1.7 |  | 
| 171 | adcroft | 1.1 |  | 
| 172 | edhill | 1.19 | \subsubsection{Conventional download method} | 
| 173 | adcroft | 1.4 | \label{sect:conventionalDownload} | 
| 174 | adcroft | 1.1 |  | 
| 175 | adcroft | 1.4 | If you do not have CVS on your system, you can download the model as a | 
| 176 | edhill | 1.15 | tar file from the web site at: | 
| 177 | cnh | 1.7 | \begin{rawhtml} <A href=http://mitgcm.org/download target="idontexist"> \end{rawhtml} | 
| 178 | adcroft | 1.1 | \begin{verbatim} | 
| 179 |  |  | http://mitgcm.org/download/ | 
| 180 |  |  | \end{verbatim} | 
| 181 | cnh | 1.7 | \begin{rawhtml} </A> \end{rawhtml} | 
| 182 | adcroft | 1.4 | The tar file still contains CVS information which we urge you not to | 
| 183 |  |  | delete; even if you do not use CVS yourself the information can help | 
| 184 | edhill | 1.15 | us if you should need to send us your copy of the code.  If a recent | 
| 185 |  |  | tar file does not exist, then please contact the developers through | 
| 186 | edhill | 1.17 | the | 
| 187 |  |  | \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml} | 
| 188 |  |  | MITgcm-support@mitgcm.org | 
| 189 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 190 |  |  | mailing list. | 
| 191 | adcroft | 1.1 |  | 
| 192 | edhill | 1.19 | \subsubsection{Upgrading from an earlier version} | 
| 193 | adcroft | 1.12 |  | 
| 194 |  |  | If you already have an earlier version of the code you can ``upgrade'' | 
| 195 |  |  | your copy instead of downloading the entire repository again. First, | 
| 196 |  |  | ``cd'' (change directory) to the top of your working copy: | 
| 197 |  |  | \begin{verbatim} | 
| 198 |  |  | % cd MITgcm | 
| 199 |  |  | \end{verbatim} | 
| 200 | edhill | 1.15 | and then issue the cvs update command such as: | 
| 201 | adcroft | 1.12 | \begin{verbatim} | 
| 202 | edhill | 1.16 | % cvs -q update -r checkpoint52i_post -d -P | 
| 203 | adcroft | 1.12 | \end{verbatim} | 
| 204 | edhill | 1.16 | This will update the ``tag'' to ``checkpoint52i\_post'', add any new | 
| 205 | adcroft | 1.12 | directories (-d) and remove any empty directories (-P). The -q option | 
| 206 |  |  | means be quiet which will reduce the number of messages you'll see in | 
| 207 |  |  | the terminal. If you have modified the code prior to upgrading, CVS | 
| 208 |  |  | will try to merge your changes with the upgrades. If there is a | 
| 209 |  |  | conflict between your modifications and the upgrade, it will report | 
| 210 |  |  | that file with a ``C'' in front, e.g.: | 
| 211 |  |  | \begin{verbatim} | 
| 212 |  |  | C model/src/ini_parms.F | 
| 213 |  |  | \end{verbatim} | 
| 214 |  |  | If the list of conflicts scrolled off the screen, you can re-issue the | 
| 215 |  |  | cvs update command and it will report the conflicts. Conflicts are | 
| 216 | edhill | 1.15 | indicated in the code by the delimites ``$<<<<<<<$'', ``======='' and | 
| 217 |  |  | ``$>>>>>>>$''. For example, | 
| 218 | edhill | 1.17 | {\small | 
| 219 | adcroft | 1.12 | \begin{verbatim} | 
| 220 |  |  | <<<<<<< ini_parms.F | 
| 221 |  |  | & bottomDragLinear,myOwnBottomDragCoefficient, | 
| 222 |  |  | ======= | 
| 223 |  |  | & bottomDragLinear,bottomDragQuadratic, | 
| 224 |  |  | >>>>>>> 1.18 | 
| 225 |  |  | \end{verbatim} | 
| 226 | edhill | 1.17 | } | 
| 227 | adcroft | 1.12 | means that you added ``myOwnBottomDragCoefficient'' to a namelist at | 
| 228 |  |  | the same time and place that we added ``bottomDragQuadratic''. You | 
| 229 |  |  | need to resolve this conflict and in this case the line should be | 
| 230 |  |  | changed to: | 
| 231 | edhill | 1.17 | {\small | 
| 232 | adcroft | 1.12 | \begin{verbatim} | 
| 233 |  |  | & bottomDragLinear,bottomDragQuadratic,myOwnBottomDragCoefficient, | 
| 234 |  |  | \end{verbatim} | 
| 235 | edhill | 1.17 | } | 
| 236 | edhill | 1.15 | and the lines with the delimiters ($<<<<<<$,======,$>>>>>>$) be deleted. | 
| 237 | adcroft | 1.12 | Unless you are making modifications which exactly parallel | 
| 238 |  |  | developments we make, these types of conflicts should be rare. | 
| 239 |  |  |  | 
| 240 |  |  | \paragraph*{Upgrading to the current pre-release version} | 
| 241 |  |  |  | 
| 242 |  |  | We don't make a ``release'' for every little patch and bug fix in | 
| 243 |  |  | order to keep the frequency of upgrades to a minimum. However, if you | 
| 244 |  |  | have run into a problem for which ``we have already fixed in the | 
| 245 |  |  | latest code'' and we haven't made a ``tag'' or ``release'' since that | 
| 246 |  |  | patch then you'll need to get the latest code: | 
| 247 |  |  | \begin{verbatim} | 
| 248 |  |  | % cvs -q update -A -d -P | 
| 249 |  |  | \end{verbatim} | 
| 250 |  |  | Unlike, the ``check-out'' and ``update'' procedures above, there is no | 
| 251 |  |  | ``tag'' or release name. The -A tells CVS to upgrade to the | 
| 252 |  |  | very latest version. As a rule, we don't recommend this since you | 
| 253 |  |  | might upgrade while we are in the processes of checking in the code so | 
| 254 |  |  | that you may only have part of a patch. Using this method of updating | 
| 255 |  |  | also means we can't tell what version of the code you are working | 
| 256 |  |  | with. So please be sure you understand what you're doing. | 
| 257 |  |  |  | 
| 258 | adcroft | 1.4 | \section{Model and directory structure} | 
| 259 | adcroft | 1.1 |  | 
| 260 | adcroft | 1.12 | The ``numerical'' model is contained within a execution environment | 
| 261 |  |  | support wrapper. This wrapper is designed to provide a general | 
| 262 |  |  | framework for grid-point models. MITgcmUV is a specific numerical | 
| 263 |  |  | model that uses the framework. Under this structure the model is split | 
| 264 |  |  | into execution environment support code and conventional numerical | 
| 265 |  |  | model code. The execution environment support code is held under the | 
| 266 |  |  | \textit{eesupp} directory. The grid point model code is held under the | 
| 267 |  |  | \textit{model} directory. Code execution actually starts in the | 
| 268 |  |  | \textit{eesupp} routines and not in the \textit{model} routines. For | 
| 269 | edhill | 1.17 | this reason the top-level \textit{MAIN.F} is in the | 
| 270 |  |  | \textit{eesupp/src} directory. In general, end-users should not need | 
| 271 |  |  | to worry about this level. The top-level routine for the numerical | 
| 272 |  |  | part of the code is in \textit{model/src/THE\_MODEL\_MAIN.F}. Here is | 
| 273 |  |  | a brief description of the directory structure of the model under the | 
| 274 |  |  | root tree (a detailed description is given in section 3: Code | 
| 275 |  |  | structure). | 
| 276 | adcroft | 1.1 |  | 
| 277 |  |  | \begin{itemize} | 
| 278 |  |  |  | 
| 279 | edhill | 1.17 | \item \textit{bin}: this directory is initially empty. It is the | 
| 280 |  |  | default directory in which to compile the code. | 
| 281 |  |  |  | 
| 282 | adcroft | 1.1 | \item \textit{diags}: contains the code relative to time-averaged | 
| 283 | edhill | 1.17 | diagnostics. It is subdivided into two subdirectories \textit{inc} | 
| 284 |  |  | and \textit{src} that contain include files (*.\textit{h} files) and | 
| 285 |  |  | Fortran subroutines (*.\textit{F} files), respectively. | 
| 286 | adcroft | 1.1 |  | 
| 287 |  |  | \item \textit{doc}: contains brief documentation notes. | 
| 288 | edhill | 1.17 |  | 
| 289 |  |  | \item \textit{eesupp}: contains the execution environment source code. | 
| 290 |  |  | Also subdivided into two subdirectories \textit{inc} and | 
| 291 |  |  | \textit{src}. | 
| 292 |  |  |  | 
| 293 |  |  | \item \textit{exe}: this directory is initially empty. It is the | 
| 294 |  |  | default directory in which to execute the code. | 
| 295 |  |  |  | 
| 296 |  |  | \item \textit{model}: this directory contains the main source code. | 
| 297 |  |  | Also subdivided into two subdirectories \textit{inc} and | 
| 298 |  |  | \textit{src}. | 
| 299 |  |  |  | 
| 300 |  |  | \item \textit{pkg}: contains the source code for the packages. Each | 
| 301 |  |  | package corresponds to a subdirectory. For example, \textit{gmredi} | 
| 302 |  |  | contains the code related to the Gent-McWilliams/Redi scheme, | 
| 303 |  |  | \textit{aim} the code relative to the atmospheric intermediate | 
| 304 |  |  | physics. The packages are described in detail in section 3. | 
| 305 |  |  |  | 
| 306 |  |  | \item \textit{tools}: this directory contains various useful tools. | 
| 307 |  |  | For example, \textit{genmake2} is a script written in csh (C-shell) | 
| 308 |  |  | that should be used to generate your makefile. The directory | 
| 309 |  |  | \textit{adjoint} contains the makefile specific to the Tangent | 
| 310 |  |  | linear and Adjoint Compiler (TAMC) that generates the adjoint code. | 
| 311 |  |  | The latter is described in details in part V. | 
| 312 |  |  |  | 
| 313 | adcroft | 1.1 | \item \textit{utils}: this directory contains various utilities. The | 
| 314 | edhill | 1.17 | subdirectory \textit{knudsen2} contains code and a makefile that | 
| 315 |  |  | compute coefficients of the polynomial approximation to the knudsen | 
| 316 |  |  | formula for an ocean nonlinear equation of state. The | 
| 317 |  |  | \textit{matlab} subdirectory contains matlab scripts for reading | 
| 318 |  |  | model output directly into matlab. \textit{scripts} contains C-shell | 
| 319 |  |  | post-processing scripts for joining processor-based and tiled-based | 
| 320 |  |  | model output. | 
| 321 |  |  |  | 
| 322 |  |  | \item \textit{verification}: this directory contains the model | 
| 323 |  |  | examples. See section \ref{sect:modelExamples}. | 
| 324 | adcroft | 1.1 |  | 
| 325 |  |  | \end{itemize} | 
| 326 |  |  |  | 
| 327 | adcroft | 1.4 | \section{Example experiments} | 
| 328 |  |  | \label{sect:modelExamples} | 
| 329 | adcroft | 1.1 |  | 
| 330 | edhill | 1.15 | %% a set of twenty-four pre-configured numerical experiments | 
| 331 |  |  |  | 
| 332 |  |  | The MITgcm distribution comes with more than a dozen pre-configured | 
| 333 |  |  | numerical experiments. Some of these example experiments are tests of | 
| 334 |  |  | individual parts of the model code, but many are fully fledged | 
| 335 |  |  | numerical simulations. A few of the examples are used for tutorial | 
| 336 |  |  | documentation in sections \ref{sect:eg-baro} - \ref{sect:eg-global}. | 
| 337 |  |  | The other examples follow the same general structure as the tutorial | 
| 338 |  |  | examples. However, they only include brief instructions in a text file | 
| 339 |  |  | called {\it README}.  The examples are located in subdirectories under | 
| 340 |  |  | the directory \textit{verification}. Each example is briefly described | 
| 341 |  |  | below. | 
| 342 | adcroft | 1.1 |  | 
| 343 | cnh | 1.8 | \subsection{Full list of model examples} | 
| 344 | adcroft | 1.1 |  | 
| 345 | cnh | 1.8 | \begin{enumerate} | 
| 346 | edhill | 1.17 |  | 
| 347 | adcroft | 1.1 | \item \textit{exp0} - single layer, ocean double gyre (barotropic with | 
| 348 | edhill | 1.15 | free-surface). This experiment is described in detail in section | 
| 349 |  |  | \ref{sect:eg-baro}. | 
| 350 | adcroft | 1.1 |  | 
| 351 | edhill | 1.15 | \item \textit{exp1} - Four layer, ocean double gyre. This experiment | 
| 352 |  |  | is described in detail in section \ref{sect:eg-baroc}. | 
| 353 |  |  |  | 
| 354 | adcroft | 1.1 | \item \textit{exp2} - 4x4 degree global ocean simulation with steady | 
| 355 | edhill | 1.15 | climatological forcing. This experiment is described in detail in | 
| 356 |  |  | section \ref{sect:eg-global}. | 
| 357 |  |  |  | 
| 358 |  |  | \item \textit{exp4} - Flow over a Gaussian bump in open-water or | 
| 359 |  |  | channel with open boundaries. | 
| 360 |  |  |  | 
| 361 |  |  | \item \textit{exp5} - Inhomogenously forced ocean convection in a | 
| 362 |  |  | doubly periodic box. | 
| 363 | adcroft | 1.1 |  | 
| 364 | cnh | 1.8 | \item \textit{front\_relax} - Relaxation of an ocean thermal front (test for | 
| 365 | adcroft | 1.1 | Gent/McWilliams scheme). 2D (Y-Z). | 
| 366 |  |  |  | 
| 367 | edhill | 1.15 | \item \textit{internal wave} - Ocean internal wave forced by open | 
| 368 |  |  | boundary conditions. | 
| 369 |  |  |  | 
| 370 | cnh | 1.8 | \item \textit{natl\_box} - Eastern subtropical North Atlantic with KPP | 
| 371 | edhill | 1.15 | scheme; 1 month integration | 
| 372 |  |  |  | 
| 373 |  |  | \item \textit{hs94.1x64x5} - Zonal averaged atmosphere using Held and | 
| 374 |  |  | Suarez '94 forcing. | 
| 375 |  |  |  | 
| 376 |  |  | \item \textit{hs94.128x64x5} - 3D atmosphere dynamics using Held and | 
| 377 |  |  | Suarez '94 forcing. | 
| 378 |  |  |  | 
| 379 | adcroft | 1.1 | \item \textit{hs94.cs-32x32x5} - 3D atmosphere dynamics using Held and | 
| 380 | edhill | 1.15 | Suarez '94 forcing on the cubed sphere. | 
| 381 |  |  |  | 
| 382 |  |  | \item \textit{aim.5l\_zon-ave} - Intermediate Atmospheric physics. | 
| 383 |  |  | Global Zonal Mean configuration, 1x64x5 resolution. | 
| 384 |  |  |  | 
| 385 |  |  | \item \textit{aim.5l\_XZ\_Equatorial\_Slice} - Intermediate | 
| 386 |  |  | Atmospheric physics, equatorial Slice configuration.  2D (X-Z). | 
| 387 |  |  |  | 
| 388 | adcroft | 1.1 | \item \textit{aim.5l\_Equatorial\_Channel} - Intermediate Atmospheric | 
| 389 | edhill | 1.15 | physics. 3D Equatorial Channel configuration. | 
| 390 |  |  |  | 
| 391 | cnh | 1.8 | \item \textit{aim.5l\_LatLon} - Intermediate Atmospheric physics. | 
| 392 | edhill | 1.15 | Global configuration, on latitude longitude grid with 128x64x5 grid | 
| 393 |  |  | points ($2.8^\circ{\rm degree}$ resolution). | 
| 394 |  |  |  | 
| 395 |  |  | \item \textit{adjustment.128x64x1} Barotropic adjustment problem on | 
| 396 |  |  | latitude longitude grid with 128x64 grid points ($2.8^\circ{\rm | 
| 397 |  |  | degree}$ resolution). | 
| 398 |  |  |  | 
| 399 |  |  | \item \textit{adjustment.cs-32x32x1} Barotropic adjustment problem on | 
| 400 |  |  | cube sphere grid with 32x32 points per face ( roughly $2.8^\circ{\rm | 
| 401 |  |  | degree}$ resolution). | 
| 402 |  |  |  | 
| 403 | cnh | 1.8 | \item \textit{advect\_cs} Two-dimensional passive advection test on | 
| 404 | edhill | 1.15 | cube sphere grid. | 
| 405 |  |  |  | 
| 406 |  |  | \item \textit{advect\_xy} Two-dimensional (horizontal plane) passive | 
| 407 |  |  | advection test on Cartesian grid. | 
| 408 |  |  |  | 
| 409 |  |  | \item \textit{advect\_yz} Two-dimensional (vertical plane) passive | 
| 410 |  |  | advection test on Cartesian grid. | 
| 411 |  |  |  | 
| 412 |  |  | \item \textit{carbon} Simple passive tracer experiment. Includes | 
| 413 |  |  | derivative calculation. Described in detail in section | 
| 414 |  |  | \ref{sect:eg-carbon-ad}. | 
| 415 | cnh | 1.8 |  | 
| 416 |  |  | \item \textit{flt\_example} Example of using float package. | 
| 417 | edhill | 1.15 |  | 
| 418 |  |  | \item \textit{global\_ocean.90x40x15} Global circulation with GM, flux | 
| 419 |  |  | boundary conditions and poles. | 
| 420 | cnh | 1.8 |  | 
| 421 | mlosch | 1.13 | \item \textit{global\_ocean\_pressure} Global circulation in pressure | 
| 422 |  |  | coordinate (non-Boussinesq ocean model). Described in detail in | 
| 423 |  |  | section \ref{sect:eg-globalpressure}. | 
| 424 | edhill | 1.15 |  | 
| 425 |  |  | \item \textit{solid-body.cs-32x32x1} Solid body rotation test for cube | 
| 426 |  |  | sphere grid. | 
| 427 | cnh | 1.8 |  | 
| 428 |  |  | \end{enumerate} | 
| 429 | adcroft | 1.1 |  | 
| 430 | adcroft | 1.4 | \subsection{Directory structure of model examples} | 
| 431 | adcroft | 1.1 |  | 
| 432 |  |  | Each example directory has the following subdirectories: | 
| 433 |  |  |  | 
| 434 |  |  | \begin{itemize} | 
| 435 |  |  | \item \textit{code}: contains the code particular to the example. At a | 
| 436 | edhill | 1.16 | minimum, this directory includes the following files: | 
| 437 | adcroft | 1.1 |  | 
| 438 | edhill | 1.16 | \begin{itemize} | 
| 439 |  |  | \item \textit{code/CPP\_EEOPTIONS.h}: declares CPP keys relative to | 
| 440 |  |  | the ``execution environment'' part of the code. The default | 
| 441 |  |  | version is located in \textit{eesupp/inc}. | 
| 442 |  |  |  | 
| 443 |  |  | \item \textit{code/CPP\_OPTIONS.h}: declares CPP keys relative to | 
| 444 |  |  | the ``numerical model'' part of the code. The default version is | 
| 445 |  |  | located in \textit{model/inc}. | 
| 446 |  |  |  | 
| 447 |  |  | \item \textit{code/SIZE.h}: declares size of underlying | 
| 448 |  |  | computational grid.  The default version is located in | 
| 449 |  |  | \textit{model/inc}. | 
| 450 |  |  | \end{itemize} | 
| 451 |  |  |  | 
| 452 |  |  | In addition, other include files and subroutines might be present in | 
| 453 |  |  | \textit{code} depending on the particular experiment. See Section 2 | 
| 454 |  |  | for more details. | 
| 455 | edhill | 1.15 |  | 
| 456 |  |  | \item \textit{input}: contains the input data files required to run | 
| 457 |  |  | the example. At a minimum, the \textit{input} directory contains the | 
| 458 |  |  | following files: | 
| 459 | adcroft | 1.1 |  | 
| 460 | edhill | 1.16 | \begin{itemize} | 
| 461 |  |  | \item \textit{input/data}: this file, written as a namelist, | 
| 462 |  |  | specifies the main parameters for the experiment. | 
| 463 |  |  |  | 
| 464 |  |  | \item \textit{input/data.pkg}: contains parameters relative to the | 
| 465 |  |  | packages used in the experiment. | 
| 466 |  |  |  | 
| 467 |  |  | \item \textit{input/eedata}: this file contains ``execution | 
| 468 |  |  | environment'' data. At present, this consists of a specification | 
| 469 |  |  | of the number of threads to use in $X$ and $Y$ under multithreaded | 
| 470 |  |  | execution. | 
| 471 |  |  | \end{itemize} | 
| 472 | edhill | 1.17 |  | 
| 473 |  |  | In addition, you will also find in this directory the forcing and | 
| 474 |  |  | topography files as well as the files describing the initial state | 
| 475 |  |  | of the experiment.  This varies from experiment to experiment. See | 
| 476 |  |  | section 2 for more details. | 
| 477 | edhill | 1.16 |  | 
| 478 |  |  | \item \textit{results}: this directory contains the output file | 
| 479 |  |  | \textit{output.txt} produced by the simulation example. This file is | 
| 480 |  |  | useful for comparison with your own output when you run the | 
| 481 |  |  | experiment. | 
| 482 | adcroft | 1.1 | \end{itemize} | 
| 483 |  |  |  | 
| 484 | edhill | 1.17 | Once you have chosen the example you want to run, you are ready to | 
| 485 |  |  | compile the code. | 
| 486 | adcroft | 1.1 |  | 
| 487 | adcroft | 1.4 | \section{Building the code} | 
| 488 |  |  | \label{sect:buildingCode} | 
| 489 |  |  |  | 
| 490 |  |  | To compile the code, we use the {\em make} program. This uses a file | 
| 491 |  |  | ({\em Makefile}) that allows us to pre-process source files, specify | 
| 492 |  |  | compiler and optimization options and also figures out any file | 
| 493 | edhill | 1.16 | dependencies. We supply a script ({\em genmake2}), described in | 
| 494 |  |  | section \ref{sect:genmake}, that automatically creates the {\em | 
| 495 |  |  | Makefile} for you. You then need to build the dependencies and | 
| 496 |  |  | compile the code. | 
| 497 | adcroft | 1.4 |  | 
| 498 |  |  | As an example, let's assume that you want to build and run experiment | 
| 499 | edhill | 1.16 | \textit{verification/exp2}. The are multiple ways and places to | 
| 500 |  |  | actually do this but here let's build the code in | 
| 501 | adcroft | 1.4 | \textit{verification/exp2/input}: | 
| 502 |  |  | \begin{verbatim} | 
| 503 |  |  | % cd verification/exp2/input | 
| 504 |  |  | \end{verbatim} | 
| 505 |  |  | First, build the {\em Makefile}: | 
| 506 |  |  | \begin{verbatim} | 
| 507 | edhill | 1.16 | % ../../../tools/genmake2 -mods=../code | 
| 508 | adcroft | 1.4 | \end{verbatim} | 
| 509 |  |  | The command line option tells {\em genmake} to override model source | 
| 510 |  |  | code with any files in the directory {\em ./code/}. | 
| 511 |  |  |  | 
| 512 | edhill | 1.16 | On many systems, the {\em genmake2} program will be able to | 
| 513 |  |  | automatically recognize the hardware, find compilers and other tools | 
| 514 |  |  | within the user's path (``echo \$PATH''), and then choose an | 
| 515 |  |  | appropriate set of options from the files contained in the {\em | 
| 516 |  |  | tools/build\_options} directory.  Under some circumstances, a user | 
| 517 |  |  | may have to create a new ``optfile'' in order to specify the exact | 
| 518 |  |  | combination of compiler, compiler flags, libraries, and other options | 
| 519 |  |  | necessary to build a particular configuration of MITgcm.  In such | 
| 520 |  |  | cases, it is generally helpful to read the existing ``optfiles'' and | 
| 521 |  |  | mimic their syntax. | 
| 522 |  |  |  | 
| 523 |  |  | Through the MITgcm-support list, the MITgcm developers are willing to | 
| 524 |  |  | provide help writing or modifing ``optfiles''.  And we encourage users | 
| 525 |  |  | to post new ``optfiles'' (particularly ones for new machines or | 
| 526 | edhill | 1.17 | architectures) to the | 
| 527 |  |  | \begin{rawhtml} <A href=''mailto:MITgcm-support@mitgcm.org"> \end{rawhtml} | 
| 528 |  |  | MITgcm-support@mitgcm.org | 
| 529 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 530 |  |  | list. | 
| 531 | edhill | 1.16 |  | 
| 532 |  |  | To specify an optfile to {\em genmake2}, the syntax is: | 
| 533 | adcroft | 1.4 | \begin{verbatim} | 
| 534 | edhill | 1.16 | % ../../../tools/genmake2 -mods=../code -of /path/to/optfile | 
| 535 | adcroft | 1.4 | \end{verbatim} | 
| 536 |  |  |  | 
| 537 | edhill | 1.16 | Once a {\em Makefile} has been generated, we create the dependencies: | 
| 538 | adcroft | 1.4 | \begin{verbatim} | 
| 539 |  |  | % make depend | 
| 540 |  |  | \end{verbatim} | 
| 541 | edhill | 1.16 | This modifies the {\em Makefile} by attaching a [long] list of files | 
| 542 |  |  | upon which other files depend. The purpose of this is to reduce | 
| 543 |  |  | re-compilation if and when you start to modify the code. The {\tt make | 
| 544 |  |  | depend} command also creates links from the model source to this | 
| 545 |  |  | directory. | 
| 546 | adcroft | 1.1 |  | 
| 547 | edhill | 1.16 | Next compile the code: | 
| 548 | adcroft | 1.4 | \begin{verbatim} | 
| 549 |  |  | % make | 
| 550 |  |  | \end{verbatim} | 
| 551 |  |  | The {\tt make} command creates an executable called \textit{mitgcmuv}. | 
| 552 | edhill | 1.16 | Additional make ``targets'' are defined within the makefile to aid in | 
| 553 |  |  | the production of adjoint and other versions of MITgcm. | 
| 554 | adcroft | 1.4 |  | 
| 555 |  |  | Now you are ready to run the model. General instructions for doing so are | 
| 556 |  |  | given in section \ref{sect:runModel}. Here, we can run the model with: | 
| 557 |  |  | \begin{verbatim} | 
| 558 |  |  | ./mitgcmuv > output.txt | 
| 559 |  |  | \end{verbatim} | 
| 560 |  |  | where we are re-directing the stream of text output to the file {\em | 
| 561 |  |  | output.txt}. | 
| 562 |  |  |  | 
| 563 |  |  |  | 
| 564 |  |  | \subsection{Building/compiling the code elsewhere} | 
| 565 |  |  |  | 
| 566 |  |  | In the example above (section \ref{sect:buildingCode}) we built the | 
| 567 |  |  | executable in the {\em input} directory of the experiment for | 
| 568 |  |  | convenience. You can also configure and compile the code in other | 
| 569 |  |  | locations, for example on a scratch disk with out having to copy the | 
| 570 |  |  | entire source tree. The only requirement to do so is you have {\tt | 
| 571 | edhill | 1.16 | genmake2} in your path or you know the absolute path to {\tt | 
| 572 |  |  | genmake2}. | 
| 573 | adcroft | 1.4 |  | 
| 574 | edhill | 1.16 | The following sections outline some possible methods of organizing | 
| 575 |  |  | your source and data. | 
| 576 | adcroft | 1.4 |  | 
| 577 |  |  | \subsubsection{Building from the {\em ../code directory}} | 
| 578 |  |  |  | 
| 579 |  |  | This is just as simple as building in the {\em input/} directory: | 
| 580 |  |  | \begin{verbatim} | 
| 581 |  |  | % cd verification/exp2/code | 
| 582 | edhill | 1.16 | % ../../../tools/genmake2 | 
| 583 | adcroft | 1.4 | % make depend | 
| 584 |  |  | % make | 
| 585 |  |  | \end{verbatim} | 
| 586 |  |  | However, to run the model the executable ({\em mitgcmuv}) and input | 
| 587 |  |  | files must be in the same place. If you only have one calculation to make: | 
| 588 |  |  | \begin{verbatim} | 
| 589 |  |  | % cd ../input | 
| 590 |  |  | % cp ../code/mitgcmuv ./ | 
| 591 |  |  | % ./mitgcmuv > output.txt | 
| 592 |  |  | \end{verbatim} | 
| 593 | cnh | 1.9 | or if you will be making multiple runs with the same executable: | 
| 594 | adcroft | 1.4 | \begin{verbatim} | 
| 595 |  |  | % cd ../ | 
| 596 |  |  | % cp -r input run1 | 
| 597 |  |  | % cp code/mitgcmuv run1 | 
| 598 |  |  | % cd run1 | 
| 599 |  |  | % ./mitgcmuv > output.txt | 
| 600 |  |  | \end{verbatim} | 
| 601 |  |  |  | 
| 602 |  |  | \subsubsection{Building from a new directory} | 
| 603 |  |  |  | 
| 604 |  |  | Since the {\em input} directory contains input files it is often more | 
| 605 | cnh | 1.9 | useful to keep {\em input} pristine and build in a new directory | 
| 606 | adcroft | 1.4 | within {\em verification/exp2/}: | 
| 607 |  |  | \begin{verbatim} | 
| 608 |  |  | % cd verification/exp2 | 
| 609 |  |  | % mkdir build | 
| 610 |  |  | % cd build | 
| 611 | edhill | 1.16 | % ../../../tools/genmake2 -mods=../code | 
| 612 | adcroft | 1.4 | % make depend | 
| 613 |  |  | % make | 
| 614 |  |  | \end{verbatim} | 
| 615 |  |  | This builds the code exactly as before but this time you need to copy | 
| 616 |  |  | either the executable or the input files or both in order to run the | 
| 617 |  |  | model. For example, | 
| 618 |  |  | \begin{verbatim} | 
| 619 |  |  | % cp ../input/* ./ | 
| 620 |  |  | % ./mitgcmuv > output.txt | 
| 621 |  |  | \end{verbatim} | 
| 622 |  |  | or if you tend to make multiple runs with the same executable then | 
| 623 |  |  | running in a new directory each time might be more appropriate: | 
| 624 |  |  | \begin{verbatim} | 
| 625 |  |  | % cd ../ | 
| 626 |  |  | % mkdir run1 | 
| 627 |  |  | % cp build/mitgcmuv run1/ | 
| 628 |  |  | % cp input/* run1/ | 
| 629 |  |  | % cd run1 | 
| 630 |  |  | % ./mitgcmuv > output.txt | 
| 631 |  |  | \end{verbatim} | 
| 632 |  |  |  | 
| 633 | edhill | 1.16 | \subsubsection{Building on a scratch disk} | 
| 634 | adcroft | 1.4 |  | 
| 635 |  |  | Model object files and output data can use up large amounts of disk | 
| 636 |  |  | space so it is often the case that you will be operating on a large | 
| 637 |  |  | scratch disk. Assuming the model source is in {\em ~/MITgcm} then the | 
| 638 |  |  | following commands will build the model in {\em /scratch/exp2-run1}: | 
| 639 |  |  | \begin{verbatim} | 
| 640 |  |  | % cd /scratch/exp2-run1 | 
| 641 | edhill | 1.16 | % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \ | 
| 642 |  |  | -mods=~/MITgcm/verification/exp2/code | 
| 643 | adcroft | 1.4 | % make depend | 
| 644 |  |  | % make | 
| 645 |  |  | \end{verbatim} | 
| 646 |  |  | To run the model here, you'll need the input files: | 
| 647 |  |  | \begin{verbatim} | 
| 648 |  |  | % cp ~/MITgcm/verification/exp2/input/* ./ | 
| 649 |  |  | % ./mitgcmuv > output.txt | 
| 650 |  |  | \end{verbatim} | 
| 651 |  |  |  | 
| 652 |  |  | As before, you could build in one directory and make multiple runs of | 
| 653 |  |  | the one experiment: | 
| 654 |  |  | \begin{verbatim} | 
| 655 |  |  | % cd /scratch/exp2 | 
| 656 |  |  | % mkdir build | 
| 657 |  |  | % cd build | 
| 658 | edhill | 1.16 | % ~/MITgcm/tools/genmake2 -rootdir=~/MITgcm \ | 
| 659 |  |  | -mods=~/MITgcm/verification/exp2/code | 
| 660 | adcroft | 1.4 | % make depend | 
| 661 |  |  | % make | 
| 662 |  |  | % cd ../ | 
| 663 |  |  | % cp -r ~/MITgcm/verification/exp2/input run2 | 
| 664 |  |  | % cd run2 | 
| 665 |  |  | % ./mitgcmuv > output.txt | 
| 666 |  |  | \end{verbatim} | 
| 667 |  |  |  | 
| 668 |  |  |  | 
| 669 | edhill | 1.24 | \subsection{Using \texttt{genmake2}} | 
| 670 | adcroft | 1.4 | \label{sect:genmake} | 
| 671 | adcroft | 1.1 |  | 
| 672 | edhill | 1.16 | To compile the code, first use the program \texttt{genmake2} (located | 
| 673 | edhill | 1.24 | in the \texttt{tools} directory) to generate a Makefile. | 
| 674 | edhill | 1.16 | \texttt{genmake2} is a shell script written to work with all | 
| 675 |  |  | ``sh''--compatible shells including bash v1, bash v2, and Bourne. | 
| 676 |  |  | Internally, \texttt{genmake2} determines the locations of needed | 
| 677 |  |  | files, the compiler, compiler options, libraries, and Unix tools.  It | 
| 678 | edhill | 1.24 | relies upon a number of ``optfiles'' located in the | 
| 679 |  |  | \texttt{tools/build\_options} directory. | 
| 680 | edhill | 1.16 |  | 
| 681 |  |  | The purpose of the optfiles is to provide all the compilation options | 
| 682 |  |  | for particular ``platforms'' (where ``platform'' roughly means the | 
| 683 |  |  | combination of the hardware and the compiler) and code configurations. | 
| 684 |  |  | Given the combinations of possible compilers and library dependencies | 
| 685 |  |  | ({\it eg.}  MPI and NetCDF) there may be numerous optfiles available | 
| 686 |  |  | for a single machine.  The naming scheme for the majority of the | 
| 687 |  |  | optfiles shipped with the code is | 
| 688 |  |  | \begin{center} | 
| 689 |  |  | {\bf OS\_HARDWARE\_COMPILER } | 
| 690 |  |  | \end{center} | 
| 691 |  |  | where | 
| 692 |  |  | \begin{description} | 
| 693 |  |  | \item[OS] is the name of the operating system (generally the | 
| 694 |  |  | lower-case output of the {\tt 'uname'} command) | 
| 695 |  |  | \item[HARDWARE] is a string that describes the CPU type and | 
| 696 |  |  | corresponds to output from the  {\tt 'uname -m'} command: | 
| 697 |  |  | \begin{description} | 
| 698 |  |  | \item[ia32] is for ``x86'' machines such as i386, i486, i586, i686, | 
| 699 |  |  | and athlon | 
| 700 |  |  | \item[ia64] is for Intel IA64 systems (eg. Itanium, Itanium2) | 
| 701 |  |  | \item[amd64] is AMD x86\_64 systems | 
| 702 |  |  | \item[ppc] is for Mac PowerPC systems | 
| 703 |  |  | \end{description} | 
| 704 |  |  | \item[COMPILER] is the compiler name (generally, the name of the | 
| 705 |  |  | FORTRAN executable) | 
| 706 |  |  | \end{description} | 
| 707 |  |  |  | 
| 708 |  |  | In many cases, the default optfiles are sufficient and will result in | 
| 709 |  |  | usable Makefiles.  However, for some machines or code configurations, | 
| 710 |  |  | new ``optfiles'' must be written. To create a new optfile, it is | 
| 711 |  |  | generally best to start with one of the defaults and modify it to suit | 
| 712 |  |  | your needs.  Like \texttt{genmake2}, the optfiles are all written | 
| 713 |  |  | using a simple ``sh''--compatible syntax.  While nearly all variables | 
| 714 |  |  | used within \texttt{genmake2} may be specified in the optfiles, the | 
| 715 |  |  | critical ones that should be defined are: | 
| 716 |  |  |  | 
| 717 |  |  | \begin{description} | 
| 718 |  |  | \item[FC] the FORTRAN compiler (executable) to use | 
| 719 |  |  | \item[DEFINES] the command-line DEFINE options passed to the compiler | 
| 720 |  |  | \item[CPP] the C pre-processor to use | 
| 721 |  |  | \item[NOOPTFLAGS] options flags for special files that should not be | 
| 722 |  |  | optimized | 
| 723 |  |  | \end{description} | 
| 724 |  |  |  | 
| 725 |  |  | For example, the optfile for a typical Red Hat Linux machine (``ia32'' | 
| 726 |  |  | architecture) using the GCC (g77) compiler is | 
| 727 |  |  | \begin{verbatim} | 
| 728 |  |  | FC=g77 | 
| 729 |  |  | DEFINES='-D_BYTESWAPIO -DWORDLENGTH=4' | 
| 730 |  |  | CPP='cpp  -traditional -P' | 
| 731 |  |  | NOOPTFLAGS='-O0' | 
| 732 |  |  | #  For IEEE, use the "-ffloat-store" option | 
| 733 |  |  | if test "x$IEEE" = x ; then | 
| 734 |  |  | FFLAGS='-Wimplicit -Wunused -Wuninitialized' | 
| 735 |  |  | FOPTIM='-O3 -malign-double -funroll-loops' | 
| 736 |  |  | else | 
| 737 |  |  | FFLAGS='-Wimplicit -Wunused -ffloat-store' | 
| 738 |  |  | FOPTIM='-O0 -malign-double' | 
| 739 |  |  | fi | 
| 740 |  |  | \end{verbatim} | 
| 741 |  |  |  | 
| 742 |  |  | If you write an optfile for an unrepresented machine or compiler, you | 
| 743 |  |  | are strongly encouraged to submit the optfile to the MITgcm project | 
| 744 |  |  | for inclusion.  Please send the file to the | 
| 745 |  |  | \begin{rawhtml} <A href="mail-to:MITgcm-support@mitgcm.org"> \end{rawhtml} | 
| 746 |  |  | \begin{center} | 
| 747 |  |  | MITgcm-support@mitgcm.org | 
| 748 |  |  | \end{center} | 
| 749 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 750 |  |  | mailing list. | 
| 751 | adcroft | 1.1 |  | 
| 752 | edhill | 1.16 | In addition to the optfiles, \texttt{genmake2} supports a number of | 
| 753 |  |  | helpful command-line options.  A complete list of these options can be | 
| 754 |  |  | obtained from: | 
| 755 |  |  | \begin{verbatim} | 
| 756 |  |  | % genmake2 -h | 
| 757 |  |  | \end{verbatim} | 
| 758 |  |  |  | 
| 759 |  |  | The most important command-line options are: | 
| 760 |  |  | \begin{description} | 
| 761 |  |  |  | 
| 762 | edhill | 1.17 | \item[\texttt{--optfile=/PATH/FILENAME}] specifies the optfile that | 
| 763 |  |  | should be used for a particular build. | 
| 764 | edhill | 1.16 |  | 
| 765 |  |  | If no "optfile" is specified (either through the command line or the | 
| 766 |  |  | MITGCM\_OPTFILE environment variable), genmake2 will try to make a | 
| 767 |  |  | reasonable guess from the list provided in {\em | 
| 768 |  |  | tools/build\_options}.  The method used for making this guess is | 
| 769 |  |  | to first determine the combination of operating system and hardware | 
| 770 |  |  | (eg. "linux\_ia32") and then find a working FORTRAN compiler within | 
| 771 |  |  | the user's path.  When these three items have been identified, | 
| 772 |  |  | genmake2 will try to find an optfile that has a matching name. | 
| 773 |  |  |  | 
| 774 | edhill | 1.22 | \item[\texttt{--pdefault='PKG1 PKG2 PKG3 ...'}] specifies the default | 
| 775 |  |  | set of packages to be used.  The normal order of precedence for | 
| 776 |  |  | packages is as follows: | 
| 777 |  |  | \begin{enumerate} | 
| 778 |  |  | \item If available, the command line (\texttt{--pdefault}) settings | 
| 779 |  |  | over-rule any others. | 
| 780 |  |  |  | 
| 781 |  |  | \item Next, \texttt{genmake2} will look for a file named | 
| 782 |  |  | ``\texttt{packages.conf}'' in the local directory or in any of the | 
| 783 |  |  | directories specified with the \texttt{--mods} option. | 
| 784 |  |  |  | 
| 785 |  |  | \item Finally, if neither of the above are available, | 
| 786 |  |  | \texttt{genmake2} will use the \texttt{/pkg/pkg\_default} file. | 
| 787 |  |  | \end{enumerate} | 
| 788 |  |  |  | 
| 789 | edhill | 1.17 | \item[\texttt{--pdepend=/PATH/FILENAME}] specifies the dependency file | 
| 790 |  |  | used for packages. | 
| 791 | edhill | 1.16 |  | 
| 792 |  |  | If not specified, the default dependency file {\em pkg/pkg\_depend} | 
| 793 |  |  | is used.  The syntax for this file is parsed on a line-by-line basis | 
| 794 |  |  | where each line containes either a comment ("\#") or a simple | 
| 795 |  |  | "PKGNAME1 (+|-)PKGNAME2" pairwise rule where the "+" or "-" symbol | 
| 796 |  |  | specifies a "must be used with" or a "must not be used with" | 
| 797 |  |  | relationship, respectively.  If no rule is specified, then it is | 
| 798 |  |  | assumed that the two packages are compatible and will function | 
| 799 |  |  | either with or without each other. | 
| 800 |  |  |  | 
| 801 | edhill | 1.17 | \item[\texttt{--adof=/path/to/file}] specifies the "adjoint" or | 
| 802 |  |  | automatic differentiation options file to be used.  The file is | 
| 803 |  |  | analogous to the ``optfile'' defined above but it specifies | 
| 804 |  |  | information for the AD build process. | 
| 805 | edhill | 1.16 |  | 
| 806 |  |  | The default file is located in {\em | 
| 807 |  |  | tools/adjoint\_options/adjoint\_default} and it defines the "TAF" | 
| 808 |  |  | and "TAMC" compilers.  An alternate version is also available at | 
| 809 |  |  | {\em tools/adjoint\_options/adjoint\_staf} that selects the newer | 
| 810 |  |  | "STAF" compiler.  As with any compilers, it is helpful to have their | 
| 811 |  |  | directories listed in your {\tt \$PATH} environment variable. | 
| 812 |  |  |  | 
| 813 | edhill | 1.17 | \item[\texttt{--mods='DIR1 DIR2 DIR3 ...'}] specifies a list of | 
| 814 |  |  | directories containing ``modifications''.  These directories contain | 
| 815 |  |  | files with names that may (or may not) exist in the main MITgcm | 
| 816 |  |  | source tree but will be overridden by any identically-named sources | 
| 817 |  |  | within the ``MODS'' directories. | 
| 818 | edhill | 1.16 |  | 
| 819 |  |  | The order of precedence for this "name-hiding" is as follows: | 
| 820 |  |  | \begin{itemize} | 
| 821 |  |  | \item ``MODS'' directories (in the order given) | 
| 822 |  |  | \item Packages either explicitly specified or provided by default | 
| 823 |  |  | (in the order given) | 
| 824 |  |  | \item Packages included due to package dependencies (in the order | 
| 825 |  |  | that that package dependencies are parsed) | 
| 826 |  |  | \item The "standard dirs" (which may have been specified by the | 
| 827 |  |  | ``-standarddirs'' option) | 
| 828 |  |  | \end{itemize} | 
| 829 |  |  |  | 
| 830 | edhill | 1.23 | \item[\texttt{--mpi}] This option enables certain MPI features (using | 
| 831 |  |  | CPP \texttt{\#define}s) within the code and is necessary for MPI | 
| 832 |  |  | builds (see Section \ref{sect:mpi-build}). | 
| 833 |  |  |  | 
| 834 | edhill | 1.17 | \item[\texttt{--make=/path/to/gmake}] Due to the poor handling of | 
| 835 |  |  | soft-links and other bugs common with the \texttt{make} versions | 
| 836 |  |  | provided by commercial Unix vendors, GNU \texttt{make} (sometimes | 
| 837 |  |  | called \texttt{gmake}) should be preferred.  This option provides a | 
| 838 |  |  | means for specifying the make executable to be used. | 
| 839 | edhill | 1.21 |  | 
| 840 |  |  | \item[\texttt{--bash=/path/to/sh}] On some (usually older UNIX) | 
| 841 |  |  | machines, the ``bash'' shell is unavailable.  To run on these | 
| 842 |  |  | systems, \texttt{genmake2} can be invoked using an ``sh'' (that is, | 
| 843 |  |  | a Bourne, POSIX, or compatible) shell.  The syntax in these | 
| 844 |  |  | circumstances is: | 
| 845 |  |  | \begin{center} | 
| 846 | edhill | 1.23 | \texttt{\%  /bin/sh genmake2 -bash=/bin/sh [...options...]} | 
| 847 | edhill | 1.21 | \end{center} | 
| 848 |  |  | where \texttt{/bin/sh} can be replaced with the full path and name | 
| 849 |  |  | of the desired shell. | 
| 850 | adcroft | 1.1 |  | 
| 851 | edhill | 1.16 | \end{description} | 
| 852 | adcroft | 1.1 |  | 
| 853 |  |  |  | 
| 854 | edhill | 1.23 | \subsection{Building with MPI} | 
| 855 |  |  | \label{sect:mpi-build} | 
| 856 |  |  |  | 
| 857 |  |  | Building MITgcm to use MPI libraries can be complicated due to the | 
| 858 |  |  | variety of different MPI implementations available, their dependencies | 
| 859 |  |  | or interactions with different compilers, and their often ad-hoc | 
| 860 |  |  | locations within file systems.  For these reasons, its generally a | 
| 861 |  |  | good idea to start by finding and reading the documentation for your | 
| 862 |  |  | machine(s) and, if necessary, seeking help from your local systems | 
| 863 |  |  | administrator. | 
| 864 |  |  |  | 
| 865 |  |  | The steps for building MITgcm with MPI support are: | 
| 866 |  |  | \begin{enumerate} | 
| 867 |  |  |  | 
| 868 |  |  | \item Determine the locations of your MPI-enabled compiler and/or MPI | 
| 869 |  |  | libraries and put them into an options file as described in Section | 
| 870 |  |  | \ref{sect:genmake}.  One can start with one of the examples in: | 
| 871 |  |  | \begin{rawhtml} <A | 
| 872 |  |  | href="http://mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm/tools/build_options/"> | 
| 873 |  |  | \end{rawhtml} | 
| 874 |  |  | \begin{center} | 
| 875 |  |  | \texttt{MITgcm/tools/build\_options/} | 
| 876 |  |  | \end{center} | 
| 877 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 878 |  |  | such as \texttt{linux\_ia32\_g77+mpi\_cg01} or | 
| 879 |  |  | \texttt{linux\_ia64\_efc+mpi} and then edit it to suit the machine at | 
| 880 |  |  | hand.  You may need help from your user guide or local systems | 
| 881 |  |  | administrator to determine the exact location of the MPI libraries. | 
| 882 |  |  | If libraries are not installed, MPI implementations and related | 
| 883 |  |  | tools are available including: | 
| 884 |  |  | \begin{itemize} | 
| 885 |  |  | \item \begin{rawhtml} <A | 
| 886 |  |  | href="http://www-unix.mcs.anl.gov/mpi/mpich/"> | 
| 887 |  |  | \end{rawhtml} | 
| 888 |  |  | MPICH | 
| 889 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 890 |  |  |  | 
| 891 |  |  | \item \begin{rawhtml} <A | 
| 892 |  |  | href="http://www.lam-mpi.org/"> | 
| 893 |  |  | \end{rawhtml} | 
| 894 |  |  | LAM/MPI | 
| 895 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 896 |  |  |  | 
| 897 |  |  | \item \begin{rawhtml} <A | 
| 898 |  |  | href="http://www.osc.edu/~pw/mpiexec/"> | 
| 899 |  |  | \end{rawhtml} | 
| 900 |  |  | MPIexec | 
| 901 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 902 |  |  | \end{itemize} | 
| 903 |  |  |  | 
| 904 |  |  | \item Build the code with the \texttt{genmake2} \texttt{-mpi} option | 
| 905 |  |  | (see Section \ref{sect:genmake}) using commands such as: | 
| 906 |  |  | {\footnotesize \begin{verbatim} | 
| 907 |  |  | %  ../../../tools/genmake2 -mods=../code -mpi -of=YOUR_OPTFILE | 
| 908 |  |  | %  make depend | 
| 909 |  |  | %  make | 
| 910 |  |  | \end{verbatim} } | 
| 911 |  |  |  | 
| 912 |  |  | \item Run the code with the appropriate MPI ``run'' or ``exec'' | 
| 913 |  |  | program provided with your particular implementation of MPI. | 
| 914 |  |  | Typical MPI packages such as MPICH will use something like: | 
| 915 |  |  | \begin{verbatim} | 
| 916 |  |  | %  mpirun -np 4 -machinefile mf ./mitgcmuv | 
| 917 |  |  | \end{verbatim} | 
| 918 |  |  | Sightly more complicated scripts may be needed for many machines | 
| 919 |  |  | since execution of the code may be controlled by both the MPI | 
| 920 |  |  | library and a job scheduling and queueing system such as PBS, | 
| 921 | edhill | 1.24 | LoadLeveller, Condor, or any of a number of similar tools.  A few | 
| 922 |  |  | example scripts (those used for our \begin{rawhtml} <A | 
| 923 |  |  | href="http://mitgcm.org/testing.html"> \end{rawhtml}regular | 
| 924 |  |  | verification runs\begin{rawhtml} </A> \end{rawhtml}) are available | 
| 925 |  |  | at: | 
| 926 |  |  | \begin{rawhtml} <A | 
| 927 |  |  | href="http://mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm_contrib/test_scripts/"> | 
| 928 |  |  | \end{rawhtml} | 
| 929 |  |  | {\footnotesize \tt | 
| 930 |  |  | http://mitgcm.org/cgi-bin/viewcvs.cgi/MITgcm\_contrib/test\_scripts/ } | 
| 931 |  |  | \begin{rawhtml} </A> \end{rawhtml} | 
| 932 | edhill | 1.23 |  | 
| 933 |  |  | \end{enumerate} | 
| 934 |  |  |  | 
| 935 |  |  |  | 
| 936 | adcroft | 1.1 |  | 
| 937 | adcroft | 1.4 | \section{Running the model} | 
| 938 |  |  | \label{sect:runModel} | 
| 939 |  |  |  | 
| 940 | edhill | 1.23 | If compilation finished succesfuully (section \ref{sect:buildingCode}) | 
| 941 |  |  | then an executable called \texttt{mitgcmuv} will now exist in the | 
| 942 |  |  | local directory. | 
| 943 | adcroft | 1.1 |  | 
| 944 | adcroft | 1.4 | To run the model as a single process (ie. not in parallel) simply | 
| 945 |  |  | type: | 
| 946 | adcroft | 1.1 | \begin{verbatim} | 
| 947 | adcroft | 1.4 | % ./mitgcmuv | 
| 948 | adcroft | 1.1 | \end{verbatim} | 
| 949 | adcroft | 1.4 | The ``./'' is a safe-guard to make sure you use the local executable | 
| 950 |  |  | in case you have others that exist in your path (surely odd if you | 
| 951 |  |  | do!). The above command will spew out many lines of text output to | 
| 952 |  |  | your screen.  This output contains details such as parameter values as | 
| 953 |  |  | well as diagnostics such as mean Kinetic energy, largest CFL number, | 
| 954 |  |  | etc. It is worth keeping this text output with the binary output so we | 
| 955 |  |  | normally re-direct the {\em stdout} stream as follows: | 
| 956 | adcroft | 1.1 | \begin{verbatim} | 
| 957 | adcroft | 1.4 | % ./mitgcmuv > output.txt | 
| 958 | adcroft | 1.1 | \end{verbatim} | 
| 959 |  |  |  | 
| 960 | edhill | 1.17 | For the example experiments in {\em verification}, an example of the | 
| 961 | adcroft | 1.4 | output is kept in {\em results/output.txt} for comparison. You can compare | 
| 962 |  |  | your {\em output.txt} with this one to check that the set-up works. | 
| 963 | adcroft | 1.1 |  | 
| 964 |  |  |  | 
| 965 |  |  |  | 
| 966 | adcroft | 1.4 | \subsection{Output files} | 
| 967 | adcroft | 1.1 |  | 
| 968 |  |  | The model produces various output files. At a minimum, the instantaneous | 
| 969 |  |  | ``state'' of the model is written out, which is made of the following files: | 
| 970 |  |  |  | 
| 971 |  |  | \begin{itemize} | 
| 972 |  |  | \item \textit{U.00000nIter} - zonal component of velocity field (m/s and $> | 
| 973 |  |  | 0 $ eastward). | 
| 974 |  |  |  | 
| 975 |  |  | \item \textit{V.00000nIter} - meridional component of velocity field (m/s | 
| 976 |  |  | and $> 0$ northward). | 
| 977 |  |  |  | 
| 978 |  |  | \item \textit{W.00000nIter} - vertical component of velocity field (ocean: | 
| 979 |  |  | m/s and $> 0$ upward, atmosphere: Pa/s and $> 0$ towards increasing pressure | 
| 980 |  |  | i.e. downward). | 
| 981 |  |  |  | 
| 982 |  |  | \item \textit{T.00000nIter} - potential temperature (ocean: $^{0}$C, | 
| 983 |  |  | atmosphere: $^{0}$K). | 
| 984 |  |  |  | 
| 985 |  |  | \item \textit{S.00000nIter} - ocean: salinity (psu), atmosphere: water vapor | 
| 986 |  |  | (g/kg). | 
| 987 |  |  |  | 
| 988 |  |  | \item \textit{Eta.00000nIter} - ocean: surface elevation (m), atmosphere: | 
| 989 |  |  | surface pressure anomaly (Pa). | 
| 990 |  |  | \end{itemize} | 
| 991 |  |  |  | 
| 992 |  |  | The chain \textit{00000nIter} consists of ten figures that specify the | 
| 993 |  |  | iteration number at which the output is written out. For example, \textit{% | 
| 994 |  |  | U.0000000300} is the zonal velocity at iteration 300. | 
| 995 |  |  |  | 
| 996 |  |  | In addition, a ``pickup'' or ``checkpoint'' file called: | 
| 997 |  |  |  | 
| 998 |  |  | \begin{itemize} | 
| 999 |  |  | \item \textit{pickup.00000nIter} | 
| 1000 |  |  | \end{itemize} | 
| 1001 |  |  |  | 
| 1002 |  |  | is written out. This file represents the state of the model in a condensed | 
| 1003 |  |  | form and is used for restarting the integration. If the C-D scheme is used, | 
| 1004 |  |  | there is an additional ``pickup'' file: | 
| 1005 |  |  |  | 
| 1006 |  |  | \begin{itemize} | 
| 1007 |  |  | \item \textit{pickup\_cd.00000nIter} | 
| 1008 |  |  | \end{itemize} | 
| 1009 |  |  |  | 
| 1010 |  |  | containing the D-grid velocity data and that has to be written out as well | 
| 1011 |  |  | in order to restart the integration. Rolling checkpoint files are the same | 
| 1012 |  |  | as the pickup files but are named differently. Their name contain the chain | 
| 1013 |  |  | \textit{ckptA} or \textit{ckptB} instead of \textit{00000nIter}. They can be | 
| 1014 |  |  | used to restart the model but are overwritten every other time they are | 
| 1015 |  |  | output to save disk space during long integrations. | 
| 1016 |  |  |  | 
| 1017 | adcroft | 1.4 | \subsection{Looking at the output} | 
| 1018 | adcroft | 1.1 |  | 
| 1019 |  |  | All the model data are written according to a ``meta/data'' file format. | 
| 1020 |  |  | Each variable is associated with two files with suffix names \textit{.data} | 
| 1021 |  |  | and \textit{.meta}. The \textit{.data} file contains the data written in | 
| 1022 |  |  | binary form (big\_endian by default). The \textit{.meta} file is a | 
| 1023 |  |  | ``header'' file that contains information about the size and the structure | 
| 1024 |  |  | of the \textit{.data} file. This way of organizing the output is | 
| 1025 |  |  | particularly useful when running multi-processors calculations. The base | 
| 1026 |  |  | version of the model includes a few matlab utilities to read output files | 
| 1027 |  |  | written in this format. The matlab scripts are located in the directory | 
| 1028 |  |  | \textit{utils/matlab} under the root tree. The script \textit{rdmds.m} reads | 
| 1029 |  |  | the data. Look at the comments inside the script to see how to use it. | 
| 1030 |  |  |  | 
| 1031 | adcroft | 1.4 | Some examples of reading and visualizing some output in {\em Matlab}: | 
| 1032 |  |  | \begin{verbatim} | 
| 1033 |  |  | % matlab | 
| 1034 |  |  | >> H=rdmds('Depth'); | 
| 1035 |  |  | >> contourf(H');colorbar; | 
| 1036 |  |  | >> title('Depth of fluid as used by model'); | 
| 1037 |  |  |  | 
| 1038 |  |  | >> eta=rdmds('Eta',10); | 
| 1039 |  |  | >> imagesc(eta');axis ij;colorbar; | 
| 1040 |  |  | >> title('Surface height at iter=10'); | 
| 1041 |  |  |  | 
| 1042 |  |  | >> eta=rdmds('Eta',[0:10:100]); | 
| 1043 |  |  | >> for n=1:11; imagesc(eta(:,:,n)');axis ij;colorbar;pause(.5);end | 
| 1044 |  |  | \end{verbatim} | 
| 1045 | adcroft | 1.1 |  | 
| 1046 |  |  | \section{Doing it yourself: customizing the code} | 
| 1047 |  |  |  | 
| 1048 |  |  | When you are ready to run the model in the configuration you want, the | 
| 1049 | edhill | 1.17 | easiest thing is to use and adapt the setup of the case studies | 
| 1050 |  |  | experiment (described previously) that is the closest to your | 
| 1051 |  |  | configuration. Then, the amount of setup will be minimized. In this | 
| 1052 |  |  | section, we focus on the setup relative to the ``numerical model'' | 
| 1053 |  |  | part of the code (the setup relative to the ``execution environment'' | 
| 1054 |  |  | part is covered in the parallel implementation section) and on the | 
| 1055 |  |  | variables and parameters that you are likely to change. | 
| 1056 | adcroft | 1.1 |  | 
| 1057 | adcroft | 1.5 | \subsection{Configuration and setup} | 
| 1058 | adcroft | 1.4 |  | 
| 1059 | edhill | 1.17 | The CPP keys relative to the ``numerical model'' part of the code are | 
| 1060 |  |  | all defined and set in the file \textit{CPP\_OPTIONS.h }in the | 
| 1061 |  |  | directory \textit{ model/inc }or in one of the \textit{code | 
| 1062 |  |  | }directories of the case study experiments under | 
| 1063 |  |  | \textit{verification.} The model parameters are defined and declared | 
| 1064 |  |  | in the file \textit{model/inc/PARAMS.h }and their default values are | 
| 1065 |  |  | set in the routine \textit{model/src/set\_defaults.F. }The default | 
| 1066 |  |  | values can be modified in the namelist file \textit{data }which needs | 
| 1067 |  |  | to be located in the directory where you will run the model. The | 
| 1068 |  |  | parameters are initialized in the routine | 
| 1069 |  |  | \textit{model/src/ini\_parms.F}.  Look at this routine to see in what | 
| 1070 |  |  | part of the namelist the parameters are located. | 
| 1071 |  |  |  | 
| 1072 |  |  | In what follows the parameters are grouped into categories related to | 
| 1073 |  |  | the computational domain, the equations solved in the model, and the | 
| 1074 |  |  | simulation controls. | 
| 1075 | adcroft | 1.1 |  | 
| 1076 | adcroft | 1.4 | \subsection{Computational domain, geometry and time-discretization} | 
| 1077 | adcroft | 1.1 |  | 
| 1078 | edhill | 1.17 | \begin{description} | 
| 1079 |  |  | \item[dimensions] \ | 
| 1080 |  |  |  | 
| 1081 | edhill | 1.18 | The number of points in the x, y, and r directions are represented | 
| 1082 |  |  | by the variables \textbf{sNx}, \textbf{sNy} and \textbf{Nr} | 
| 1083 |  |  | respectively which are declared and set in the file | 
| 1084 |  |  | \textit{model/inc/SIZE.h}.  (Again, this assumes a mono-processor | 
| 1085 |  |  | calculation. For multiprocessor calculations see the section on | 
| 1086 |  |  | parallel implementation.) | 
| 1087 | edhill | 1.17 |  | 
| 1088 |  |  | \item[grid] \ | 
| 1089 |  |  |  | 
| 1090 |  |  | Three different grids are available: cartesian, spherical polar, and | 
| 1091 | edhill | 1.18 | curvilinear (which includes the cubed sphere). The grid is set | 
| 1092 |  |  | through the logical variables \textbf{usingCartesianGrid}, | 
| 1093 |  |  | \textbf{usingSphericalPolarGrid}, and \textbf{usingCurvilinearGrid}. | 
| 1094 |  |  | In the case of spherical and curvilinear grids, the southern | 
| 1095 |  |  | boundary is defined through the variable \textbf{phiMin} which | 
| 1096 |  |  | corresponds to the latitude of the southern most cell face (in | 
| 1097 |  |  | degrees). The resolution along the x and y directions is controlled | 
| 1098 |  |  | by the 1D arrays \textbf{delx} and \textbf{dely} (in meters in the | 
| 1099 |  |  | case of a cartesian grid, in degrees otherwise).  The vertical grid | 
| 1100 |  |  | spacing is set through the 1D array \textbf{delz} for the ocean (in | 
| 1101 |  |  | meters) or \textbf{delp} for the atmosphere (in Pa).  The variable | 
| 1102 |  |  | \textbf{Ro\_SeaLevel} represents the standard position of Sea-Level | 
| 1103 |  |  | in ``R'' coordinate. This is typically set to 0m for the ocean | 
| 1104 |  |  | (default value) and 10$^{5}$Pa for the atmosphere. For the | 
| 1105 |  |  | atmosphere, also set the logical variable \textbf{groundAtK1} to | 
| 1106 |  |  | \texttt{'.TRUE.'} which puts the first level (k=1) at the lower | 
| 1107 | edhill | 1.17 | boundary (ground). | 
| 1108 |  |  |  | 
| 1109 |  |  | For the cartesian grid case, the Coriolis parameter $f$ is set | 
| 1110 | edhill | 1.18 | through the variables \textbf{f0} and \textbf{beta} which correspond | 
| 1111 |  |  | to the reference Coriolis parameter (in s$^{-1}$) and | 
| 1112 |  |  | $\frac{\partial f}{ \partial y}$(in m$^{-1}$s$^{-1}$) respectively. | 
| 1113 |  |  | If \textbf{beta } is set to a nonzero value, \textbf{f0} is the | 
| 1114 |  |  | value of $f$ at the southern edge of the domain. | 
| 1115 | edhill | 1.17 |  | 
| 1116 |  |  | \item[topography - full and partial cells] \ | 
| 1117 |  |  |  | 
| 1118 |  |  | The domain bathymetry is read from a file that contains a 2D (x,y) | 
| 1119 |  |  | map of depths (in m) for the ocean or pressures (in Pa) for the | 
| 1120 |  |  | atmosphere. The file name is represented by the variable | 
| 1121 | edhill | 1.18 | \textbf{bathyFile}. The file is assumed to contain binary numbers | 
| 1122 |  |  | giving the depth (pressure) of the model at each grid cell, ordered | 
| 1123 |  |  | with the x coordinate varying fastest. The points are ordered from | 
| 1124 |  |  | low coordinate to high coordinate for both axes. The model code | 
| 1125 |  |  | applies without modification to enclosed, periodic, and double | 
| 1126 |  |  | periodic domains. Periodicity is assumed by default and is | 
| 1127 | edhill | 1.17 | suppressed by setting the depths to 0m for the cells at the limits | 
| 1128 |  |  | of the computational domain (note: not sure this is the case for the | 
| 1129 |  |  | atmosphere). The precision with which to read the binary data is | 
| 1130 | edhill | 1.18 | controlled by the integer variable \textbf{readBinaryPrec} which can | 
| 1131 | edhill | 1.17 | take the value \texttt{32} (single precision) or \texttt{64} (double | 
| 1132 | edhill | 1.18 | precision). See the matlab program \textit{gendata.m} in the | 
| 1133 |  |  | \textit{input} directories under \textit{verification} to see how | 
| 1134 | edhill | 1.17 | the bathymetry files are generated for the case study experiments. | 
| 1135 |  |  |  | 
| 1136 | edhill | 1.18 | To use the partial cell capability, the variable \textbf{hFacMin} | 
| 1137 |  |  | needs to be set to a value between 0 and 1 (it is set to 1 by | 
| 1138 |  |  | default) corresponding to the minimum fractional size of the cell. | 
| 1139 |  |  | For example if the bottom cell is 500m thick and \textbf{hFacMin} is | 
| 1140 |  |  | set to 0.1, the actual thickness of the cell (i.e. used in the code) | 
| 1141 |  |  | can cover a range of discrete values 50m apart from 50m to 500m | 
| 1142 |  |  | depending on the value of the bottom depth (in \textbf{bathyFile}) | 
| 1143 |  |  | at this point. | 
| 1144 | edhill | 1.17 |  | 
| 1145 |  |  | Note that the bottom depths (or pressures) need not coincide with | 
| 1146 | edhill | 1.18 | the models levels as deduced from \textbf{delz} or \textbf{delp}. | 
| 1147 |  |  | The model will interpolate the numbers in \textbf{bathyFile} so that | 
| 1148 |  |  | they match the levels obtained from \textbf{delz} or \textbf{delp} | 
| 1149 |  |  | and \textbf{hFacMin}. | 
| 1150 | edhill | 1.17 |  | 
| 1151 |  |  | (Note: the atmospheric case is a bit more complicated than what is | 
| 1152 |  |  | written here I think. To come soon...) | 
| 1153 |  |  |  | 
| 1154 |  |  | \item[time-discretization] \ | 
| 1155 |  |  |  | 
| 1156 |  |  | The time steps are set through the real variables \textbf{deltaTMom} | 
| 1157 |  |  | and \textbf{deltaTtracer} (in s) which represent the time step for | 
| 1158 |  |  | the momentum and tracer equations, respectively. For synchronous | 
| 1159 |  |  | integrations, simply set the two variables to the same value (or you | 
| 1160 |  |  | can prescribe one time step only through the variable | 
| 1161 |  |  | \textbf{deltaT}). The Adams-Bashforth stabilizing parameter is set | 
| 1162 |  |  | through the variable \textbf{abEps} (dimensionless). The stagger | 
| 1163 |  |  | baroclinic time stepping can be activated by setting the logical | 
| 1164 | edhill | 1.18 | variable \textbf{staggerTimeStep} to \texttt{'.TRUE.'}. | 
| 1165 | adcroft | 1.1 |  | 
| 1166 | edhill | 1.17 | \end{description} | 
| 1167 | adcroft | 1.1 |  | 
| 1168 |  |  |  | 
| 1169 | adcroft | 1.4 | \subsection{Equation of state} | 
| 1170 | adcroft | 1.1 |  | 
| 1171 | mlosch | 1.13 | First, because the model equations are written in terms of | 
| 1172 |  |  | perturbations, a reference thermodynamic state needs to be specified. | 
| 1173 |  |  | This is done through the 1D arrays \textbf{tRef} and \textbf{sRef}. | 
| 1174 |  |  | \textbf{tRef} specifies the reference potential temperature profile | 
| 1175 |  |  | (in $^{o}$C for the ocean and $^{o}$K for the atmosphere) starting | 
| 1176 |  |  | from the level k=1. Similarly, \textbf{sRef} specifies the reference | 
| 1177 |  |  | salinity profile (in ppt) for the ocean or the reference specific | 
| 1178 |  |  | humidity profile (in g/kg) for the atmosphere. | 
| 1179 |  |  |  | 
| 1180 |  |  | The form of the equation of state is controlled by the character | 
| 1181 |  |  | variables \textbf{buoyancyRelation} and \textbf{eosType}. | 
| 1182 | edhill | 1.18 | \textbf{buoyancyRelation} is set to \texttt{'OCEANIC'} by default and | 
| 1183 |  |  | needs to be set to \texttt{'ATMOSPHERIC'} for atmosphere simulations. | 
| 1184 |  |  | In this case, \textbf{eosType} must be set to \texttt{'IDEALGAS'}. | 
| 1185 | mlosch | 1.13 | For the ocean, two forms of the equation of state are available: | 
| 1186 | edhill | 1.18 | linear (set \textbf{eosType} to \texttt{'LINEAR'}) and a polynomial | 
| 1187 |  |  | approximation to the full nonlinear equation ( set \textbf{eosType} to | 
| 1188 |  |  | \texttt{'POLYNOMIAL'}). In the linear case, you need to specify the | 
| 1189 |  |  | thermal and haline expansion coefficients represented by the variables | 
| 1190 |  |  | \textbf{tAlpha} (in K$^{-1}$) and \textbf{sBeta} (in ppt$^{-1}$). For | 
| 1191 |  |  | the nonlinear case, you need to generate a file of polynomial | 
| 1192 |  |  | coefficients called \textit{POLY3.COEFFS}. To do this, use the program | 
| 1193 | mlosch | 1.13 | \textit{utils/knudsen2/knudsen2.f} under the model tree (a Makefile is | 
| 1194 |  |  | available in the same directory and you will need to edit the number | 
| 1195 |  |  | and the values of the vertical levels in \textit{knudsen2.f} so that | 
| 1196 |  |  | they match those of your configuration). | 
| 1197 |  |  |  | 
| 1198 |  |  | There there are also higher polynomials for the equation of state: | 
| 1199 |  |  | \begin{description} | 
| 1200 | edhill | 1.18 | \item[\texttt{'UNESCO'}:] The UNESCO equation of state formula of | 
| 1201 | mlosch | 1.13 | Fofonoff and Millard \cite{fofonoff83}. This equation of state | 
| 1202 | edhill | 1.18 | assumes in-situ temperature, which is not a model variable; {\em its | 
| 1203 |  |  | use is therefore discouraged, and it is only listed for | 
| 1204 |  |  | completeness}. | 
| 1205 |  |  | \item[\texttt{'JMD95Z'}:] A modified UNESCO formula by Jackett and | 
| 1206 | mlosch | 1.13 | McDougall \cite{jackett95}, which uses the model variable potential | 
| 1207 | edhill | 1.18 | temperature as input. The \texttt{'Z'} indicates that this equation | 
| 1208 | mlosch | 1.13 | of state uses a horizontally and temporally constant pressure | 
| 1209 |  |  | $p_{0}=-g\rho_{0}z$. | 
| 1210 | edhill | 1.18 | \item[\texttt{'JMD95P'}:] A modified UNESCO formula by Jackett and | 
| 1211 | mlosch | 1.13 | McDougall \cite{jackett95}, which uses the model variable potential | 
| 1212 | edhill | 1.18 | temperature as input. The \texttt{'P'} indicates that this equation | 
| 1213 | mlosch | 1.13 | of state uses the actual hydrostatic pressure of the last time | 
| 1214 |  |  | step. Lagging the pressure in this way requires an additional pickup | 
| 1215 |  |  | file for restarts. | 
| 1216 | edhill | 1.18 | \item[\texttt{'MDJWF'}:] The new, more accurate and less expensive | 
| 1217 | mlosch | 1.13 | equation of state by McDougall et~al. \cite{mcdougall03}. It also | 
| 1218 |  |  | requires lagging the pressure and therefore an additional pickup | 
| 1219 |  |  | file for restarts. | 
| 1220 |  |  | \end{description} | 
| 1221 |  |  | For none of these options an reference profile of temperature or | 
| 1222 |  |  | salinity is required. | 
| 1223 | adcroft | 1.1 |  | 
| 1224 | adcroft | 1.4 | \subsection{Momentum equations} | 
| 1225 | adcroft | 1.1 |  | 
| 1226 | edhill | 1.18 | In this section, we only focus for now on the parameters that you are | 
| 1227 |  |  | likely to change, i.e. the ones relative to forcing and dissipation | 
| 1228 |  |  | for example.  The details relevant to the vector-invariant form of the | 
| 1229 |  |  | equations and the various advection schemes are not covered for the | 
| 1230 |  |  | moment. We assume that you use the standard form of the momentum | 
| 1231 |  |  | equations (i.e. the flux-form) with the default advection scheme. | 
| 1232 |  |  | Also, there are a few logical variables that allow you to turn on/off | 
| 1233 |  |  | various terms in the momentum equation. These variables are called | 
| 1234 |  |  | \textbf{momViscosity, momAdvection, momForcing, useCoriolis, | 
| 1235 |  |  | momPressureForcing, momStepping} and \textbf{metricTerms }and are | 
| 1236 |  |  | assumed to be set to \texttt{'.TRUE.'} here.  Look at the file | 
| 1237 |  |  | \textit{model/inc/PARAMS.h }for a precise definition of these | 
| 1238 |  |  | variables. | 
| 1239 | adcroft | 1.1 |  | 
| 1240 | edhill | 1.17 | \begin{description} | 
| 1241 |  |  | \item[initialization] \ | 
| 1242 |  |  |  | 
| 1243 |  |  | The velocity components are initialized to 0 unless the simulation | 
| 1244 |  |  | is starting from a pickup file (see section on simulation control | 
| 1245 |  |  | parameters). | 
| 1246 |  |  |  | 
| 1247 |  |  | \item[forcing] \ | 
| 1248 |  |  |  | 
| 1249 |  |  | This section only applies to the ocean. You need to generate | 
| 1250 | edhill | 1.18 | wind-stress data into two files \textbf{zonalWindFile} and | 
| 1251 |  |  | \textbf{meridWindFile} corresponding to the zonal and meridional | 
| 1252 | edhill | 1.17 | components of the wind stress, respectively (if you want the stress | 
| 1253 |  |  | to be along the direction of only one of the model horizontal axes, | 
| 1254 |  |  | you only need to generate one file). The format of the files is | 
| 1255 |  |  | similar to the bathymetry file. The zonal (meridional) stress data | 
| 1256 |  |  | are assumed to be in Pa and located at U-points (V-points). As for | 
| 1257 |  |  | the bathymetry, the precision with which to read the binary data is | 
| 1258 | edhill | 1.18 | controlled by the variable \textbf{readBinaryPrec}.  See the matlab | 
| 1259 |  |  | program \textit{gendata.m} in the \textit{input} directories under | 
| 1260 |  |  | \textit{verification} to see how simple analytical wind forcing data | 
| 1261 |  |  | are generated for the case study experiments. | 
| 1262 | edhill | 1.17 |  | 
| 1263 |  |  | There is also the possibility of prescribing time-dependent periodic | 
| 1264 |  |  | forcing. To do this, concatenate the successive time records into a | 
| 1265 | edhill | 1.18 | single file (for each stress component) ordered in a (x,y,t) fashion | 
| 1266 |  |  | and set the following variables: \textbf{periodicExternalForcing }to | 
| 1267 |  |  | \texttt{'.TRUE.'}, \textbf{externForcingPeriod }to the period (in s) | 
| 1268 |  |  | of which the forcing varies (typically 1 month), and | 
| 1269 |  |  | \textbf{externForcingCycle} to the repeat time (in s) of the forcing | 
| 1270 |  |  | (typically 1 year -- note: \textbf{ externForcingCycle} must be a | 
| 1271 |  |  | multiple of \textbf{externForcingPeriod}).  With these variables set | 
| 1272 |  |  | up, the model will interpolate the forcing linearly at each | 
| 1273 |  |  | iteration. | 
| 1274 | edhill | 1.17 |  | 
| 1275 |  |  | \item[dissipation] \ | 
| 1276 |  |  |  | 
| 1277 |  |  | The lateral eddy viscosity coefficient is specified through the | 
| 1278 | edhill | 1.18 | variable \textbf{viscAh} (in m$^{2}$s$^{-1}$). The vertical eddy | 
| 1279 |  |  | viscosity coefficient is specified through the variable | 
| 1280 |  |  | \textbf{viscAz} (in m$^{2}$s$^{-1}$) for the ocean and | 
| 1281 |  |  | \textbf{viscAp} (in Pa$^{2}$s$^{-1}$) for the atmosphere.  The | 
| 1282 |  |  | vertical diffusive fluxes can be computed implicitly by setting the | 
| 1283 |  |  | logical variable \textbf{implicitViscosity }to \texttt{'.TRUE.'}. | 
| 1284 |  |  | In addition, biharmonic mixing can be added as well through the | 
| 1285 |  |  | variable \textbf{viscA4} (in m$^{4}$s$^{-1}$). On a spherical polar | 
| 1286 |  |  | grid, you might also need to set the variable \textbf{cosPower} | 
| 1287 |  |  | which is set to 0 by default and which represents the power of | 
| 1288 |  |  | cosine of latitude to multiply viscosity. Slip or no-slip conditions | 
| 1289 |  |  | at lateral and bottom boundaries are specified through the logical | 
| 1290 |  |  | variables \textbf{no\_slip\_sides} and \textbf{no\_slip\_bottom}. If | 
| 1291 |  |  | set to \texttt{'.FALSE.'}, free-slip boundary conditions are | 
| 1292 |  |  | applied. If no-slip boundary conditions are applied at the bottom, a | 
| 1293 |  |  | bottom drag can be applied as well. Two forms are available: linear | 
| 1294 |  |  | (set the variable \textbf{bottomDragLinear} in s$ ^{-1}$) and | 
| 1295 |  |  | quadratic (set the variable \textbf{bottomDragQuadratic} in | 
| 1296 |  |  | m$^{-1}$). | 
| 1297 | edhill | 1.17 |  | 
| 1298 |  |  | The Fourier and Shapiro filters are described elsewhere. | 
| 1299 |  |  |  | 
| 1300 |  |  | \item[C-D scheme] \ | 
| 1301 |  |  |  | 
| 1302 |  |  | If you run at a sufficiently coarse resolution, you will need the | 
| 1303 |  |  | C-D scheme for the computation of the Coriolis terms. The | 
| 1304 |  |  | variable\textbf{\ tauCD}, which represents the C-D scheme coupling | 
| 1305 |  |  | timescale (in s) needs to be set. | 
| 1306 |  |  |  | 
| 1307 |  |  | \item[calculation of pressure/geopotential] \ | 
| 1308 |  |  |  | 
| 1309 |  |  | First, to run a non-hydrostatic ocean simulation, set the logical | 
| 1310 | edhill | 1.18 | variable \textbf{nonHydrostatic} to \texttt{'.TRUE.'}. The pressure | 
| 1311 | edhill | 1.17 | field is then inverted through a 3D elliptic equation. (Note: this | 
| 1312 |  |  | capability is not available for the atmosphere yet.) By default, a | 
| 1313 |  |  | hydrostatic simulation is assumed and a 2D elliptic equation is used | 
| 1314 |  |  | to invert the pressure field. The parameters controlling the | 
| 1315 |  |  | behaviour of the elliptic solvers are the variables | 
| 1316 | edhill | 1.18 | \textbf{cg2dMaxIters} and \textbf{cg2dTargetResidual } for | 
| 1317 |  |  | the 2D case and \textbf{cg3dMaxIters} and | 
| 1318 |  |  | \textbf{cg3dTargetResidual} for the 3D case. You probably won't need to | 
| 1319 | edhill | 1.17 | alter the default values (are we sure of this?). | 
| 1320 |  |  |  | 
| 1321 |  |  | For the calculation of the surface pressure (for the ocean) or | 
| 1322 |  |  | surface geopotential (for the atmosphere) you need to set the | 
| 1323 | edhill | 1.18 | logical variables \textbf{rigidLid} and \textbf{implicitFreeSurface} | 
| 1324 |  |  | (set one to \texttt{'.TRUE.'} and the other to \texttt{'.FALSE.'} | 
| 1325 |  |  | depending on how you want to deal with the ocean upper or atmosphere | 
| 1326 |  |  | lower boundary). | 
| 1327 | adcroft | 1.1 |  | 
| 1328 | edhill | 1.17 | \end{description} | 
| 1329 | adcroft | 1.1 |  | 
| 1330 | adcroft | 1.4 | \subsection{Tracer equations} | 
| 1331 | adcroft | 1.1 |  | 
| 1332 | edhill | 1.18 | This section covers the tracer equations i.e. the potential | 
| 1333 |  |  | temperature equation and the salinity (for the ocean) or specific | 
| 1334 |  |  | humidity (for the atmosphere) equation. As for the momentum equations, | 
| 1335 |  |  | we only describe for now the parameters that you are likely to change. | 
| 1336 |  |  | The logical variables \textbf{tempDiffusion} \textbf{tempAdvection} | 
| 1337 |  |  | \textbf{tempForcing}, and \textbf{tempStepping} allow you to turn | 
| 1338 |  |  | on/off terms in the temperature equation (same thing for salinity or | 
| 1339 |  |  | specific humidity with variables \textbf{saltDiffusion}, | 
| 1340 |  |  | \textbf{saltAdvection} etc.). These variables are all assumed here to | 
| 1341 |  |  | be set to \texttt{'.TRUE.'}. Look at file \textit{model/inc/PARAMS.h} | 
| 1342 |  |  | for a precise definition. | 
| 1343 | adcroft | 1.1 |  | 
| 1344 | edhill | 1.17 | \begin{description} | 
| 1345 |  |  | \item[initialization] \ | 
| 1346 |  |  |  | 
| 1347 |  |  | The initial tracer data can be contained in the binary files | 
| 1348 | edhill | 1.18 | \textbf{hydrogThetaFile} and \textbf{hydrogSaltFile}. These files | 
| 1349 |  |  | should contain 3D data ordered in an (x,y,r) fashion with k=1 as the | 
| 1350 |  |  | first vertical level.  If no file names are provided, the tracers | 
| 1351 |  |  | are then initialized with the values of \textbf{tRef} and | 
| 1352 |  |  | \textbf{sRef} mentioned above (in the equation of state section). In | 
| 1353 | edhill | 1.17 | this case, the initial tracer data are uniform in x and y for each | 
| 1354 |  |  | depth level. | 
| 1355 |  |  |  | 
| 1356 |  |  | \item[forcing] \ | 
| 1357 |  |  |  | 
| 1358 |  |  | This part is more relevant for the ocean, the procedure for the | 
| 1359 |  |  | atmosphere not being completely stabilized at the moment. | 
| 1360 |  |  |  | 
| 1361 |  |  | A combination of fluxes data and relaxation terms can be used for | 
| 1362 | edhill | 1.18 | driving the tracer equations.  For potential temperature, heat flux | 
| 1363 | edhill | 1.17 | data (in W/m$ ^{2}$) can be stored in the 2D binary file | 
| 1364 | edhill | 1.18 | \textbf{surfQfile}.  Alternatively or in addition, the forcing can | 
| 1365 |  |  | be specified through a relaxation term. The SST data to which the | 
| 1366 |  |  | model surface temperatures are restored to are supposed to be stored | 
| 1367 |  |  | in the 2D binary file \textbf{thetaClimFile}. The corresponding | 
| 1368 |  |  | relaxation time scale coefficient is set through the variable | 
| 1369 |  |  | \textbf{tauThetaClimRelax} (in s). The same procedure applies for | 
| 1370 |  |  | salinity with the variable names \textbf{EmPmRfile}, | 
| 1371 |  |  | \textbf{saltClimFile}, and \textbf{tauSaltClimRelax} for freshwater | 
| 1372 |  |  | flux (in m/s) and surface salinity (in ppt) data files and | 
| 1373 |  |  | relaxation time scale coefficient (in s), respectively. Also for | 
| 1374 |  |  | salinity, if the CPP key \textbf{USE\_NATURAL\_BCS} is turned on, | 
| 1375 |  |  | natural boundary conditions are applied i.e. when computing the | 
| 1376 |  |  | surface salinity tendency, the freshwater flux is multiplied by the | 
| 1377 |  |  | model surface salinity instead of a constant salinity value. | 
| 1378 | edhill | 1.17 |  | 
| 1379 |  |  | As for the other input files, the precision with which to read the | 
| 1380 |  |  | data is controlled by the variable \textbf{readBinaryPrec}. | 
| 1381 |  |  | Time-dependent, periodic forcing can be applied as well following | 
| 1382 |  |  | the same procedure used for the wind forcing data (see above). | 
| 1383 |  |  |  | 
| 1384 |  |  | \item[dissipation] \ | 
| 1385 |  |  |  | 
| 1386 |  |  | Lateral eddy diffusivities for temperature and salinity/specific | 
| 1387 | edhill | 1.18 | humidity are specified through the variables \textbf{diffKhT} and | 
| 1388 |  |  | \textbf{diffKhS} (in m$^{2}$/s). Vertical eddy diffusivities are | 
| 1389 |  |  | specified through the variables \textbf{diffKzT} and | 
| 1390 |  |  | \textbf{diffKzS} (in m$^{2}$/s) for the ocean and \textbf{diffKpT | 
| 1391 |  |  | }and \textbf{diffKpS} (in Pa$^{2}$/s) for the atmosphere. The | 
| 1392 |  |  | vertical diffusive fluxes can be computed implicitly by setting the | 
| 1393 |  |  | logical variable \textbf{implicitDiffusion} to \texttt{'.TRUE.'}. | 
| 1394 |  |  | In addition, biharmonic diffusivities can be specified as well | 
| 1395 |  |  | through the coefficients \textbf{diffK4T} and \textbf{diffK4S} (in | 
| 1396 | edhill | 1.17 | m$^{4}$/s). Note that the cosine power scaling (specified through | 
| 1397 | edhill | 1.18 | \textbf{cosPower}---see the momentum equations section) is applied to | 
| 1398 |  |  | the tracer diffusivities (Laplacian and biharmonic) as well. The | 
| 1399 | edhill | 1.17 | Gent and McWilliams parameterization for oceanic tracers is | 
| 1400 |  |  | described in the package section. Finally, note that tracers can be | 
| 1401 |  |  | also subject to Fourier and Shapiro filtering (see the corresponding | 
| 1402 |  |  | section on these filters). | 
| 1403 |  |  |  | 
| 1404 |  |  | \item[ocean convection] \ | 
| 1405 |  |  |  | 
| 1406 |  |  | Two options are available to parameterize ocean convection: one is | 
| 1407 |  |  | to use the convective adjustment scheme. In this case, you need to | 
| 1408 |  |  | set the variable \textbf{cadjFreq}, which represents the frequency | 
| 1409 |  |  | (in s) with which the adjustment algorithm is called, to a non-zero | 
| 1410 |  |  | value (if set to a negative value by the user, the model will set it | 
| 1411 |  |  | to the tracer time step). The other option is to parameterize | 
| 1412 |  |  | convection with implicit vertical diffusion. To do this, set the | 
| 1413 | edhill | 1.18 | logical variable \textbf{implicitDiffusion} to \texttt{'.TRUE.'} | 
| 1414 |  |  | and the real variable \textbf{ivdc\_kappa} to a value (in m$^{2}$/s) | 
| 1415 | edhill | 1.17 | you wish the tracer vertical diffusivities to have when mixing | 
| 1416 |  |  | tracers vertically due to static instabilities. Note that | 
| 1417 | edhill | 1.18 | \textbf{cadjFreq} and \textbf{ivdc\_kappa}can not both have non-zero | 
| 1418 |  |  | value. | 
| 1419 | adcroft | 1.1 |  | 
| 1420 | edhill | 1.17 | \end{description} | 
| 1421 | adcroft | 1.1 |  | 
| 1422 | adcroft | 1.4 | \subsection{Simulation controls} | 
| 1423 | adcroft | 1.1 |  | 
| 1424 | edhill | 1.18 | The model ''clock'' is defined by the variable \textbf{deltaTClock} | 
| 1425 |  |  | (in s) which determines the IO frequencies and is used in tagging | 
| 1426 |  |  | output.  Typically, you will set it to the tracer time step for | 
| 1427 |  |  | accelerated runs (otherwise it is simply set to the default time step | 
| 1428 |  |  | \textbf{deltaT}).  Frequency of checkpointing and dumping of the model | 
| 1429 |  |  | state are referenced to this clock (see below). | 
| 1430 | adcroft | 1.1 |  | 
| 1431 | edhill | 1.17 | \begin{description} | 
| 1432 |  |  | \item[run duration] \ | 
| 1433 |  |  |  | 
| 1434 |  |  | The beginning of a simulation is set by specifying a start time (in | 
| 1435 | edhill | 1.18 | s) through the real variable \textbf{startTime} or by specifying an | 
| 1436 | edhill | 1.17 | initial iteration number through the integer variable | 
| 1437 |  |  | \textbf{nIter0}. If these variables are set to nonzero values, the | 
| 1438 | edhill | 1.18 | model will look for a ''pickup'' file \textit{pickup.0000nIter0} to | 
| 1439 |  |  | restart the integration. The end of a simulation is set through the | 
| 1440 |  |  | real variable \textbf{endTime} (in s).  Alternatively, you can | 
| 1441 |  |  | specify instead the number of time steps to execute through the | 
| 1442 |  |  | integer variable \textbf{nTimeSteps}. | 
| 1443 | edhill | 1.17 |  | 
| 1444 |  |  | \item[frequency of output] \ | 
| 1445 |  |  |  | 
| 1446 |  |  | Real variables defining frequencies (in s) with which output files | 
| 1447 | edhill | 1.18 | are written on disk need to be set up. \textbf{dumpFreq} controls | 
| 1448 | edhill | 1.17 | the frequency with which the instantaneous state of the model is | 
| 1449 | edhill | 1.18 | saved. \textbf{chkPtFreq} and \textbf{pchkPtFreq} control the output | 
| 1450 |  |  | frequency of rolling and permanent checkpoint files, respectively. | 
| 1451 |  |  | See section 1.5.1 Output files for the definition of model state and | 
| 1452 |  |  | checkpoint files. In addition, time-averaged fields can be written | 
| 1453 |  |  | out by setting the variable \textbf{taveFreq} (in s).  The precision | 
| 1454 |  |  | with which to write the binary data is controlled by the integer | 
| 1455 |  |  | variable w\textbf{riteBinaryPrec} (set it to \texttt{32} or | 
| 1456 |  |  | \texttt{64}). | 
| 1457 | adcroft | 1.1 |  | 
| 1458 | edhill | 1.17 | \end{description} | 
| 1459 | adcroft | 1.1 |  | 
| 1460 | mlosch | 1.13 |  | 
| 1461 |  |  | %%% Local Variables: | 
| 1462 |  |  | %%% mode: latex | 
| 1463 |  |  | %%% TeX-master: t | 
| 1464 |  |  | %%% End: |