# Changeset 9667 for NEMO/trunk/doc/tex_sub/chap_LBC.tex

Ignore:
Timestamp:
2018-05-28T17:47:05+02:00 (3 years ago)
Message:

trunk: cyclic north-south periodicity and nperio cleaning, see #2093

File:
1 edited

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 r9407 At the model domain boundaries several choices are offered: closed, cyclic east-west, south symmetric across the equator, a north-fold, and combination closed-north fold or cyclic-north-fold. The north-fold boundary condition is associated with the 3-pole ORCA mesh. cyclic north-south, a north-fold, and combination closed-north fold or bi-cyclic east-west and north-fold. The north-fold boundary condition is associated with the 3-pole ORCA mesh. % ------------------------------------------------------------------------------------------------------------- %        Closed, cyclic, south symmetric (\np{jperio}\forcode{ = 0..2}) %        Closed, cyclic (\np{jperio}\forcode{ = 0..2}) % ------------------------------------------------------------------------------------------------------------- \subsection{Closed, cyclic, south symmetric (\protect\np{jperio}\forcode{= 0..2})} \subsection{Closed, cyclic (\protect\np{jperio}\forcode{= [0127]})} \label{subsec:LBC_jperio012} The choice of closed, cyclic or symmetric model domain boundary condition is made by setting \np{jperio} to 0, 1 or 2 in namelist \ngn{namcfg}. Each time such a boundary The choice of closed or cyclic model domain boundary condition is made by setting \np{jperio} to 0, 1, 2 or 7 in namelist \ngn{namcfg}. Each time such a boundary condition is needed, it is set by a call to routine \mdl{lbclnk}. The computation of momentum and tracer trends proceeds from $i=2$ to $i=jpi-1$ and from $j=2$ to and the last column to the value of the second one (\autoref{fig:LBC_jperio}-a). Whatever flows out of the eastern (western) end of the basin enters the western (eastern) end. Note that there is no option for north-south cyclic or for doubly cyclic cases. \item[For symmetric boundary condition across the equator (\np{jperio}\forcode{ = 2})], last rows, and first and last columns are set to zero (closed). The row of symmetry is chosen to be the $u$- and $T-$points equator line ($j=2$, i.e. at the southern end of the domain). For arrays defined at $u-$ or $T-$points, the first row is set to the value of the third row while for most of $v$- and $f$-point arrays ($v$, $\zeta$, $j\psi$, but \gmcomment{not sure why this is "but"} scalar arrays such as eddy coefficients) the first row is set to minus the value of the second row (\autoref{fig:LBC_jperio}-b). Note that this boundary condition is not yet available for the case of a massively parallel computer (\textbf{key{\_}mpp} defined). (eastern) end. \item[For cyclic north-south boundary (\np{jperio}\forcode{ = 2})], first and last columns are set to zero (closed) whilst the first row is set to the value of the last-but-one row and the last row to the value of the second one (\autoref{fig:LBC_jperio}-a). Whatever flows out of the northern (southern) end of the basin enters the southern (northern) end. \item[Bi-cyclic east-west and north-south boundary (\np{jperio}\forcode{ = 7})] combines cases 1 and 2. \end{description}