Changeset 11445 for NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex
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NEMO/trunk/doc/latex/NEMO/subfiles/chap_LBC.tex
r11435 r11445 151 151 \end{description} 152 152 153 Note that when the bottom topography is entirely represented by the $s$-coor -dinates (pure $s$-coordinate),153 Note that when the bottom topography is entirely represented by the $s$-coordinates (pure $s$-coordinate), 154 154 the lateral boundary condition on tangential velocity is of much less importance as 155 155 it is only applied next to the coast where the minimum water depth can be quite shallow. … … 408 408 Options are defined through the \nam{bdy} \nam{bdy\_dta} namelist variables. 409 409 The BDY module is the core implementation of open boundary conditions for regional configurations on 410 temperature, salinity, barotropic and baroclinic velocities, as well as ice concentration, ice and snow thicknesses ).410 temperature, salinity, barotropic and baroclinic velocities, as well as ice concentration, ice and snow thicknesses. 411 411 412 412 The BDY module was modelled on the OBC module (see \NEMO\ 3.4) and shares many features and 413 413 a similar coding structure \citep{chanut_rpt05}. 414 414 The specification of the location of the open boundary is completely flexible and 415 allows for example the open boundary to follow an isobath or other irregular contour.415 allows any type of setup, from regular boundaries to irregular contour (it includes the possibility to set an open boundary able to follow an isobath). 416 416 Boundary data files used with versions of \NEMO\ prior to Version 3.4 may need to be re-ordered to work with this version. 417 417 See the section on the Input Boundary Data Files for details. … … 461 461 462 462 If external boundary data is required then the \nam{bdy\_dta} namelist must be defined. 463 One \nam{bdy\_dta} namelist is required for each boundary set in the order in which 464 the boundary sets are defined in nambdy. 463 One \nam{bdy\_dta} namelist is required for each boundary set, adopting the same order of indexes in which the boundary sets are defined in nambdy. 465 464 In the example given, two boundary sets have been defined. The first one is reading data file in the \nam{bdy\_dta} namelist shown above 466 and the second one is using data from intial condition (no namelist bloc needed).465 and the second one is using data from intial condition (no namelist block needed). 467 466 The boundary data is read in using the fldread module, 468 467 so the \nam{bdy\_dta} namelist is in the format required for fldread. 469 For each variable required, the filename, the frequency of the files and470 the frequency of the data in the files isgiven.468 For each required variable, the filename, the frequency of the files and 469 the frequency of the data in the files are given. 471 470 Also whether or not time-interpolation is required and whether the data is climatological (time-cyclic) data.\\ 472 471 … … 479 478 the latter used to make any adjustment to the velocity fields due to differences in the total water depths between the two vertical grids.\\ 480 479 481 In the example namelists given, two boundary sets are defined.480 In the example of given namelists, two boundary sets are defined. 482 481 The first set is defined via a file and applies FRS conditions to temperature and salinity and 483 482 Flather conditions to the barotropic variables. No condition specified for the baroclinic velocity and sea-ice. … … 616 615 Each open boundary set is defined as a list of points. 617 616 The information is stored in the arrays $nbi$, $nbj$, and $nbr$ in the $idx\_bdy$ structure. 618 The $nbi$ and $nbj$ arrays define the local $(i,j)$ ind ices of each point in the boundary zone and619 the $nbr$ array defines the discrete distance from the boundary with $nbr=1$ meaningthat620 the point is next to the edge of the model domain and $nbr>1$ showingthat621 the point is increasingly further away from the edge of the model domain.617 The $nbi$ and $nbj$ arrays define the local $(i,j)$ indexes of each point in the boundary zone and 618 the $nbr$ array defines the discrete distance from the boundary: $nbr=1$ means that 619 the boundary point is next to the edge of the model domain, while $nbr>1$ means that 620 the boundary point is increasingly further away from the edge of the model domain. 622 621 A set of $nbi$, $nbj$, and $nbr$ arrays is defined for each of the $T$, $U$ and $V$ grids. 623 622 Figure \autoref{fig:LBC_bdy_geom} shows an example of an irregular boundary. … … 626 625 by reading in a ``\ifile{coordinates.bdy}'' file. 627 626 The nambdy\_index namelist defines a series of straight-line segments for north, east, south and west boundaries. 628 One nambdy\_index namelist bloc is needed for each boundary condition defined by indexes.627 One nambdy\_index namelist block is needed for each boundary condition defined by indexes. 629 628 For the northern boundary, \texttt{nbdysegn} gives the number of segments, 630 629 \jp{jpjnob} gives the $j$ index for each segment and \jp{jpindt} and … … 634 633 635 634 The boundary geometry may also be defined from a ``\ifile{coordinates.bdy}'' file. 636 Figure \autoref{fig:LBC_nc_header} gives an example of the header information from such a file .635 Figure \autoref{fig:LBC_nc_header} gives an example of the header information from such a file, based on the description of geometrical setup given above. 637 636 The file should contain the index arrays for each of the $T$, $U$ and $V$ grids. 638 637 The arrays must be in order of increasing $nbr$. … … 644 643 For some choices of irregular boundary the model domain may contain areas of ocean which 645 644 are not part of the computational domain. 646 For example if an open boundary is defined along an isobath, say at the shelf break,645 For example, if an open boundary is defined along an isobath, say at the shelf break, 647 646 then the areas of ocean outside of this boundary will need to be masked out. 648 647 This can be done by reading a mask file defined as \np{cn\_mask\_file} in the nam\_bdy namelist.
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