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branches/2013/dev_LOCEAN_2013/DOC/TexFiles/Chapters/Chap_DOM.tex
r3764 r4147 1 1 % ================================================================ 2 % Chapter 2 ÑSpace and Time Domain (DOM)2 % Chapter 2 � Space and Time Domain (DOM) 3 3 % ================================================================ 4 4 \chapter{Space Domain (DOM) } … … 24 24 directory routines as well as the DOM (DOMain) directory. 25 25 26 $\ $\newline % force a new lign e26 $\ $\newline % force a new lign 27 27 28 28 % ================================================================ … … 274 274 \label{DOM_size} 275 275 276 The total size of the computational domain is set by the parameters \jp{jpiglo}, 277 \jp{jpjglo} and \jp{jpk} in the $i$, $j$ and $k$ directions respectively. They are 278 given as parameters in the \mdl{par\_oce} module\footnote{When a specific 279 configuration is used (ORCA2 global ocean, etc...) the parameter are actually 280 defined in additional files introduced by \mdl{par\_oce} module via CPP 281 \textit{include} command. For example, ORCA2 parameters are set in 282 \textit{par\_ORCA\_R2.h90} file}. The use of parameters rather than variables 283 (together with dynamic allocation of arrays) was chosen because it ensured that 284 the compiler would optimize the executable code efficiently, especially on vector 285 machines (optimization may be less efficient when the problem size is unknown 286 at the time of compilation). Nevertheless, it is possible to set up the code with full 287 dynamical allocation by using the AGRIF packaged \citep{Debreu_al_CG2008}. 288 % 289 \gmcomment{ add the following ref 290 \colorbox{yellow}{(ref part of the doc)} } 291 % 292 Note that are other parameters in \mdl{par\_oce} that refer to the domain size. 293 The two parameters $jpidta$ and $jpjdta$ may be larger than $jpiglo$, $jpjglo$ 276 The total size of the computational domain is set by the parameters \np{jpiglo}, 277 \np{jpjglo} and \np{jpkdta} in the $i$, $j$ and $k$ directions respectively. They are 278 given as namelist variables in the \ngn{namcfg} namelist. 279 280 Note that are other namelist variables in the \ngn{namcfg} namelist that refer to 281 the domain size. 282 The two variables \np{jpidta} and \np{jpjdta} may be larger than \np{jpiglo}, \np{jpjglo} 294 283 when the user wants to use only a sub-region of a given configuration. This is 295 284 the "zoom" capability described in \S\ref{MISC_zoom}. In most applications of … … 300 289 301 290 302 $\ $\newline % force a new lign e291 $\ $\newline % force a new lign 303 292 304 293 % ================================================================ … … 388 377 389 378 The user has three options available in defining a horizontal grid, which involve 390 the parameter $jphgr\_mesh$ of the \mdl{par\_oce} module.379 the namelist variable \np{jphgr\_mesh} of the \ngn{namcfg} namelist. 391 380 \begin{description} 392 \item[\ jp{jphgr\_mesh}=0] The most general curvilinear orthogonal grids.381 \item[\np{jphgr\_mesh}=0] The most general curvilinear orthogonal grids. 393 382 The coordinates and their first derivatives with respect to $i$ and $j$ are provided 394 383 in a input file (\ifile{coordinates}), read in \rou{hgr\_read} subroutine of the domhgr module. 395 \item[\ jp{jphgr\_mesh}=1 to 5] A few simple analytical grids are provided (see below).384 \item[\np{jphgr\_mesh}=1 to 5] A few simple analytical grids are provided (see below). 396 385 For other analytical grids, the \mdl{domhgr} module must be modified by the user. 397 386 \end{description} 398 387 399 388 There are two simple cases of geographical grids on the sphere. With 400 \ jp{jphgr\_mesh}=1, the grid (expressed in degrees) is regular in space,401 with grid sizes specified by parameters \ pp{ppe1\_deg} and \pp{ppe2\_deg},389 \np{jphgr\_mesh}=1, the grid (expressed in degrees) is regular in space, 390 with grid sizes specified by parameters \np{ppe1\_deg} and \np{ppe2\_deg}, 402 391 respectively. Such a geographical grid can be very anisotropic at high latitudes 403 392 because of the convergence of meridians (the zonal scale factors $e_1$ 404 393 become much smaller than the meridional scale factors $e_2$). The Mercator 405 grid (\ jp{jphgr\_mesh}=4) avoids this anisotropy by refining the meridional scale394 grid (\np{jphgr\_mesh}=4) avoids this anisotropy by refining the meridional scale 406 395 factors in the same way as the zonal ones. In this case, meridional scale factors 407 396 and latitudes are calculated analytically using the formulae appropriate for 408 a Mercator projection, based on \ pp{ppe1\_deg} which is a reference grid spacing397 a Mercator projection, based on \np{ppe1\_deg} which is a reference grid spacing 409 398 at the equator (this applies even when the geographical equator is situated outside 410 399 the model domain). … … 412 401 \gmcomment{ give here the analytical expression of the Mercator mesh} 413 402 %%% 414 In these two cases (\ jp{jphgr\_mesh}=1 or 4), the grid position is defined by the415 longitude and latitude of the south-westernmost point (\ pp{ppglamt0}416 and \ pp{ppgphi0}). Note that for the Mercator grid the user need only provide403 In these two cases (\np{jphgr\_mesh}=1 or 4), the grid position is defined by the 404 longitude and latitude of the south-westernmost point (\np{ppglamt0} 405 and \np{ppgphi0}). Note that for the Mercator grid the user need only provide 417 406 an approximate starting latitude: the real latitude will be recalculated analytically, 418 407 in order to ensure that the equator corresponds to line passing through $t$- … … 420 409 421 410 Rectangular grids ignoring the spherical geometry are defined with 422 \ jp{jphgr\_mesh} = 2, 3, 5. The domain is either an $f$-plane (\jp{jphgr\_mesh} = 2,423 Coriolis factor is constant) or a beta-plane (\ jp{jphgr\_mesh} = 3, the Coriolis factor411 \np{jphgr\_mesh} = 2, 3, 5. The domain is either an $f$-plane (\np{jphgr\_mesh} = 2, 412 Coriolis factor is constant) or a beta-plane (\np{jphgr\_mesh} = 3, the Coriolis factor 424 413 is linear in the $j$-direction). The grid size is uniform in meter in each direction, 425 and given by the parameters \ pp{ppe1\_m} and \pp{ppe2\_m} respectively.414 and given by the parameters \np{ppe1\_m} and \np{ppe2\_m} respectively. 426 415 The zonal grid coordinate (\textit{glam} arrays) is in kilometers, starting at zero 427 416 with the first $t$-point. The meridional coordinate (gphi. arrays) is in kilometers, 428 417 and the second $t$-point corresponds to coordinate $gphit=0$. The input 429 parameter \pp{ppglam0} is ignored. \pp{ppgphi0} is used to set the reference418 variable \np{ppglam0} is ignored. \np{ppgphi0} is used to set the reference 430 419 latitude for computation of the Coriolis parameter. In the case of the beta plane, 431 \ pp{ppgphi0} corresponds to the center of the domain. Finally, the special case432 \ jp{jphgr\_mesh}=5 corresponds to a beta plane in a rotated domain for the420 \np{ppgphi0} corresponds to the center of the domain. Finally, the special case 421 \np{jphgr\_mesh}=5 corresponds to a beta plane in a rotated domain for the 433 422 GYRE configuration, representing a classical mid-latitude double gyre system. 434 423 The rotation allows us to maximize the jet length relative to the gyre areas … … 436 425 437 426 The choice of the grid must be consistent with the boundary conditions specified 438 by the parameter \ jp{jperio} (see {\S\ref{LBC}).427 by the parameter \np{jperio} (see {\S\ref{LBC}). 439 428 440 429 % ------------------------------------------------------------------------------------------------------------- … … 446 435 All the arrays relating to a particular ocean model configuration (grid-point 447 436 position, scale factors, masks) can be saved in files if $\np{nn\_msh} \not= 0$ 448 (namelist parameter). This can be particularly useful for plots and off-line437 (namelist variable in \ngn{namdom}). This can be particularly useful for plots and off-line 449 438 diagnostics. In some cases, the user may choose to make a local modification 450 439 of a scale factor in the code. This is the case in global configurations when … … 454 443 the output grid written when $\np{nn\_msh} \not=0$ is no more equal to the input grid. 455 444 456 $\ $\newline % force a new lign e445 $\ $\newline % force a new lign 457 446 458 447 % ================================================================ … … 467 456 %------------------------------------------------------------------------------------------------------------- 468 457 458 Variables are defined through the \ngn{namzgr} and \ngn{namdom} namelists. 469 459 In the vertical, the model mesh is determined by four things: 470 460 (1) the bathymetry given in meters ; … … 553 543 \item[\np{nn\_bathy} = 0] a flat-bottom domain is defined. The total depth $z_w (jpk)$ 554 544 is given by the coordinate transformation. The domain can either be a closed 555 basin or a periodic channel depending on the parameter \ jp{jperio}.545 basin or a periodic channel depending on the parameter \np{jperio}. 556 546 \item[\np{nn\_bathy} = -1] a domain with a bump of topography one third of the 557 547 domain width at the central latitude. This is meant for the "EEL-R5" configuration, … … 599 589 vertical scale factors. The user must provide the analytical expression of both 600 590 $z_0$ and its first derivative with respect to $k$. This is done in routine \mdl{domzgr} 601 through statement functions, using parameters provided in the \ textit{par\_oce.h90} file.602 603 It is possible to define a simple regular vertical grid by giving zero stretching (\ pp{ppacr=0}).604 In that case, the parameters \jp{jpk} (number of $w$-levels) and \ pp{pphmax}591 through statement functions, using parameters provided in the \ngn{namcfg} namelist. 592 593 It is possible to define a simple regular vertical grid by giving zero stretching (\np{ppacr=0}). 594 In that case, the parameters \jp{jpk} (number of $w$-levels) and \np{pphmax} 605 595 (total ocean depth in meters) fully define the grid. 606 596 … … 639 629 scale factors as a function of the model levels are shown in Fig.~\ref{Fig_zgr} and 640 630 given in Table \ref{Tab_orca_zgr}. Those values correspond to the parameters 641 \ pp{ppsur}, \pp{ppa0}, \pp{ppa1}, \pp{ppkth} in the parameter file \mdl{par\_oce}.631 \np{ppsur}, \np{ppa0}, \np{ppa1}, \np{ppkth} in \ngn{namcfg} namelist. 642 632 643 633 Rather than entering parameters $h_{sur}$, $h_{0}$, and $h_{1}$ directly, it is 644 634 possible to recalculate them. In that case the user sets 645 \ pp{ppsur}=\pp{ppa0}=\pp{ppa1}=\pp{pp\_to\_be\_computed}, in \mdl{par\_oce},635 \np{ppsur}=\np{ppa0}=\np{ppa1}=999999., in \ngn{namcfg} namelist, 646 636 and specifies instead the four following parameters: 647 637 \begin{itemize} 648 \item \ pp{ppacr}=$h_{cr} $: stretching factor (nondimensional). The larger649 \ pp{ppacr}, the smaller the stretching. Values from $3$ to $10$ are usual.650 \item \ pp{ppkth}=$h_{th} $: is approximately the model level at which maximum638 \item \np{ppacr}=$h_{cr} $: stretching factor (nondimensional). The larger 639 \np{ppacr}, the smaller the stretching. Values from $3$ to $10$ are usual. 640 \item \np{ppkth}=$h_{th} $: is approximately the model level at which maximum 651 641 stretching occurs (nondimensional, usually of order 1/2 or 2/3 of \jp{jpk}) 652 \item \ pp{ppdzmin}: minimum thickness for the top layer (in meters)653 \item \ pp{pphmax}: total depth of the ocean (meters).642 \item \np{ppdzmin}: minimum thickness for the top layer (in meters) 643 \item \np{pphmax}: total depth of the ocean (meters). 654 644 \end{itemize} 655 645 As an example, for the $45$ layers used in the DRAKKAR configuration those 656 parameters are: \jp{jpk}=46, \ pp{ppacr}=9, \pp{ppkth}=23.563, \pp{ppdzmin}=6m,657 \ pp{pphmax}=5750m.646 parameters are: \jp{jpk}=46, \np{ppacr}=9, \np{ppkth}=23.563, \np{ppdzmin}=6m, 647 \np{pphmax}=5750m. 658 648 659 649 %>>>>>>>>>>>>>>>>>>>>>>>>>>>> … … 720 710 is allowed to have either a smaller or larger thickness than $e_{3t}(jpk)$: the 721 711 maximum thickness allowed is $2*e_{3t}(jpk-1)$. This has to be kept in mind when 722 specifying the maximum depth \pp{pphmax} in partial steps: for example, with 723 \pp{pphmax}$=5750~m$ for the DRAKKAR 45 layer grid, the maximum ocean depth 712 specifying values in \ngn{namdom} namelist, as the maximum depth \np{pphmax} 713 in partial steps: for example, with 714 \np{pphmax}$=5750~m$ for the DRAKKAR 45 layer grid, the maximum ocean depth 724 715 allowed is actually $6000~m$ (the default thickness $e_{3t}(jpk-1)$ being $250~m$). 725 716 Two variables in the namdom namelist are used to define the partial step … … 740 731 \namdisplay{namzgr_sco} 741 732 %-------------------------------------------------------------------------------------------------------------- 733 Options are defined in \ngn{namzgr\_sco}. 742 734 In $s$-coordinate (\np{ln\_sco}~=~true), the depth and thickness of the model 743 735 levels are defined from the product of a depth field and either a stretching … … 905 897 %------------------------------------------------------------------------------------------ 906 898 899 Options are defined in \ngn{namtsd}. 907 900 By default, the ocean start from rest (the velocity field is set to zero) and the initialization of 908 901 temperature and salinity fields is controlled through the \np{ln\_tsd\_ini} namelist parameter.
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