2 |
% $Name$ |
% $Name$ |
3 |
|
|
4 |
\section[Global Ocean MITgcm Example]{Global Ocean Simulation at $4^\circ$ Resolution} |
\section[Global Ocean MITgcm Example]{Global Ocean Simulation at $4^\circ$ Resolution} |
5 |
\label{www:tutorials} |
%\label{www:tutorials} |
6 |
\label{sect:eg-global} |
\label{sec:eg-global} |
7 |
\begin{rawhtml} |
\begin{rawhtml} |
8 |
<!-- CMIREDIR:eg-global: --> |
<!-- CMIREDIR:eg-global: --> |
9 |
\end{rawhtml} |
\end{rawhtml} |
38 |
processor desktop computer. |
processor desktop computer. |
39 |
\\ |
\\ |
40 |
\subsection{Overview} |
\subsection{Overview} |
41 |
\label{www:tutorials} |
%\label{www:tutorials} |
42 |
|
|
43 |
The model is forced with climatological wind stress data and surface |
The model is forced with climatological wind stress data and surface |
44 |
flux data from DaSilva \cite{DaSilva94}. Climatological data |
flux data from DaSilva \cite{DaSilva94}. Climatological data |
52 |
in the model surface layer. |
in the model surface layer. |
53 |
|
|
54 |
\begin{eqnarray} |
\begin{eqnarray} |
55 |
\label{EQ:eg-global-global_forcing} |
\label{eq:eg-global-global_forcing} |
56 |
\label{EQ:eg-global-global_forcing_fu} |
\label{eq:eg-global-global_forcing_fu} |
57 |
{\cal F}_{u} & = & \frac{\tau_{x}}{\rho_{0} \Delta z_{s}} |
{\cal F}_{u} & = & \frac{\tau_{x}}{\rho_{0} \Delta z_{s}} |
58 |
\\ |
\\ |
59 |
\label{EQ:eg-global-global_forcing_fv} |
\label{eq:eg-global-global_forcing_fv} |
60 |
{\cal F}_{v} & = & \frac{\tau_{y}}{\rho_{0} \Delta z_{s}} |
{\cal F}_{v} & = & \frac{\tau_{y}}{\rho_{0} \Delta z_{s}} |
61 |
\\ |
\\ |
62 |
\label{EQ:eg-global-global_forcing_ft} |
\label{eq:eg-global-global_forcing_ft} |
63 |
{\cal F}_{\theta} & = & - \lambda_{\theta} ( \theta - \theta^{\ast} ) |
{\cal F}_{\theta} & = & - \lambda_{\theta} ( \theta - \theta^{\ast} ) |
64 |
- \frac{1}{C_{p} \rho_{0} \Delta z_{s}}{\cal Q} |
- \frac{1}{C_{p} \rho_{0} \Delta z_{s}}{\cal Q} |
65 |
\\ |
\\ |
66 |
\label{EQ:eg-global-global_forcing_fs} |
\label{eq:eg-global-global_forcing_fs} |
67 |
{\cal F}_{s} & = & - \lambda_{s} ( S - S^{\ast} ) |
{\cal F}_{s} & = & - \lambda_{s} ( S - S^{\ast} ) |
68 |
+ \frac{S_{0}}{\Delta z_{s}}({\cal E} - {\cal P} - {\cal R}) |
+ \frac{S_{0}}{\Delta z_{s}}({\cal E} - {\cal P} - {\cal R}) |
69 |
\end{eqnarray} |
\end{eqnarray} |
92 |
$\cal{E}-\cal{P}-\cal{R}$) have units of ${\rm ppt}$ and ${\rm m}~{\rm s}^{-1}$ |
$\cal{E}-\cal{P}-\cal{R}$) have units of ${\rm ppt}$ and ${\rm m}~{\rm s}^{-1}$ |
93 |
respectively. The source files and procedures for ingesting this data into the |
respectively. The source files and procedures for ingesting this data into the |
94 |
simulation are described in the experiment configuration discussion in section |
simulation are described in the experiment configuration discussion in section |
95 |
\ref{SEC:eg-global-clim_ocn_examp_exp_config}. |
\ref{sec:eg-global-clim_ocn_examp_exp_config}. |
96 |
|
|
97 |
|
|
98 |
\subsection{Discrete Numerical Configuration} |
\subsection{Discrete Numerical Configuration} |
99 |
\label{www:tutorials} |
%\label{www:tutorials} |
100 |
|
|
101 |
|
|
102 |
The model is configured in hydrostatic form. The domain is discretised with |
The model is configured in hydrostatic form. The domain is discretised with |
147 |
\cite{marshall:97a} is employed. A Laplacian operator, $\nabla^2$, provides viscous |
\cite{marshall:97a} is employed. A Laplacian operator, $\nabla^2$, provides viscous |
148 |
dissipation. Thermal and haline diffusion is also represented by a Laplacian operator. |
dissipation. Thermal and haline diffusion is also represented by a Laplacian operator. |
149 |
|
|
150 |
Wind-stress forcing is added to the momentum equations in (\ref{EQ:eg-global-model_equations}) |
Wind-stress forcing is added to the momentum equations in (\ref{eq:eg-global-model_equations}) |
151 |
for both the zonal flow, $u$ and the meridional flow $v$, according to equations |
for both the zonal flow, $u$ and the meridional flow $v$, according to equations |
152 |
(\ref{EQ:eg-global-global_forcing_fu}) and (\ref{EQ:eg-global-global_forcing_fv}). |
(\ref{eq:eg-global-global_forcing_fu}) and (\ref{eq:eg-global-global_forcing_fv}). |
153 |
Thermodynamic forcing inputs are added to the equations |
Thermodynamic forcing inputs are added to the equations |
154 |
in (\ref{EQ:eg-global-model_equations}) for |
in (\ref{eq:eg-global-model_equations}) for |
155 |
potential temperature, $\theta$, and salinity, $S$, according to equations |
potential temperature, $\theta$, and salinity, $S$, according to equations |
156 |
(\ref{EQ:eg-global-global_forcing_ft}) and (\ref{EQ:eg-global-global_forcing_fs}). |
(\ref{eq:eg-global-global_forcing_ft}) and (\ref{eq:eg-global-global_forcing_fs}). |
157 |
This produces a set of equations solved in this configuration as follows: |
This produces a set of equations solved in this configuration as follows: |
158 |
|
|
159 |
\begin{eqnarray} |
\begin{eqnarray} |
160 |
\label{EQ:eg-global-model_equations} |
\label{eq:eg-global-model_equations} |
161 |
\frac{Du}{Dt} - fv + |
\frac{Du}{Dt} - fv + |
162 |
\frac{1}{\rho}\frac{\partial p^{'}}{\partial x} - |
\frac{1}{\rho}\frac{\partial p^{'}}{\partial x} - |
163 |
\nabla_{h}\cdot A_{h}\nabla_{h}u - |
\nabla_{h}\cdot A_{h}\nabla_{h}u - |
214 |
\\ |
\\ |
215 |
|
|
216 |
\subsubsection{Numerical Stability Criteria} |
\subsubsection{Numerical Stability Criteria} |
217 |
\label{www:tutorials} |
%\label{www:tutorials} |
218 |
|
|
219 |
The Laplacian dissipation coefficient, $A_{h}$, is set to $5 \times 10^5 m s^{-1}$. |
The Laplacian dissipation coefficient, $A_{h}$, is set to $5 \times 10^5 m s^{-1}$. |
220 |
This value is chosen to yield a Munk layer width \cite{adcroft:95}, |
This value is chosen to yield a Munk layer width \cite{adcroft:95}, |
221 |
\begin{eqnarray} |
\begin{eqnarray} |
222 |
\label{EQ:eg-global-munk_layer} |
\label{eq:eg-global-munk_layer} |
223 |
&& M_{w} = \pi ( \frac { A_{h} }{ \beta } )^{\frac{1}{3}} |
&& M_{w} = \pi ( \frac { A_{h} }{ \beta } )^{\frac{1}{3}} |
224 |
\end{eqnarray} |
\end{eqnarray} |
225 |
|
|
233 |
$\delta t_{v}=40~{\rm minutes}$ for momentum terms. With this time step, the stability |
$\delta t_{v}=40~{\rm minutes}$ for momentum terms. With this time step, the stability |
234 |
parameter to the horizontal Laplacian friction \cite{adcroft:95} |
parameter to the horizontal Laplacian friction \cite{adcroft:95} |
235 |
\begin{eqnarray} |
\begin{eqnarray} |
236 |
\label{EQ:eg-global-laplacian_stability} |
\label{eq:eg-global-laplacian_stability} |
237 |
&& S_{l} = 4 \frac{A_{h} \delta t_{v}}{{\Delta x}^2} |
&& S_{l} = 4 \frac{A_{h} \delta t_{v}}{{\Delta x}^2} |
238 |
\end{eqnarray} |
\end{eqnarray} |
239 |
|
|
245 |
\noindent The vertical dissipation coefficient, $A_{z}$, is set to |
\noindent The vertical dissipation coefficient, $A_{z}$, is set to |
246 |
$1\times10^{-3} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
$1\times10^{-3} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
247 |
\begin{eqnarray} |
\begin{eqnarray} |
248 |
\label{EQ:eg-global-laplacian_stability_z} |
\label{eq:eg-global-laplacian_stability_z} |
249 |
S_{l} = 4 \frac{A_{z} \delta t_{v}}{{\Delta z}^2} |
S_{l} = 4 \frac{A_{z} \delta t_{v}}{{\Delta z}^2} |
250 |
\end{eqnarray} |
\end{eqnarray} |
251 |
|
|
260 |
related to $K_{h}$ will be at $\phi=80^{\circ}$ where $\Delta x \approx 77 {\rm km}$. |
related to $K_{h}$ will be at $\phi=80^{\circ}$ where $\Delta x \approx 77 {\rm km}$. |
261 |
Here the stability parameter |
Here the stability parameter |
262 |
\begin{eqnarray} |
\begin{eqnarray} |
263 |
\label{EQ:eg-global-laplacian_stability_xtheta} |
\label{eq:eg-global-laplacian_stability_xtheta} |
264 |
S_{l} = \frac{4 K_{h} \delta t_{\theta}}{{\Delta x}^2} |
S_{l} = \frac{4 K_{h} \delta t_{\theta}}{{\Delta x}^2} |
265 |
\end{eqnarray} |
\end{eqnarray} |
266 |
evaluates to $0.07$, well below the stability limit of $S_{l} \approx 0.5$. The |
evaluates to $0.07$, well below the stability limit of $S_{l} \approx 0.5$. The |
267 |
stability parameter related to $K_{z}$ |
stability parameter related to $K_{z}$ |
268 |
\begin{eqnarray} |
\begin{eqnarray} |
269 |
\label{EQ:eg-global-laplacian_stability_ztheta} |
\label{eq:eg-global-laplacian_stability_ztheta} |
270 |
S_{l} = \frac{4 K_{z} \delta t_{\theta}}{{\Delta z}^2} |
S_{l} = \frac{4 K_{z} \delta t_{\theta}}{{\Delta z}^2} |
271 |
\end{eqnarray} |
\end{eqnarray} |
272 |
evaluates to $0.005$ for $\min(\Delta z)=50{\rm m}$, well below the stability limit |
evaluates to $0.005$ for $\min(\Delta z)=50{\rm m}$, well below the stability limit |
277 |
\cite{adcroft:95} |
\cite{adcroft:95} |
278 |
|
|
279 |
\begin{eqnarray} |
\begin{eqnarray} |
280 |
\label{EQ:eg-global-inertial_stability} |
\label{eq:eg-global-inertial_stability} |
281 |
S_{i} = f^{2} {\delta t_v}^2 |
S_{i} = f^{2} {\delta t_v}^2 |
282 |
\end{eqnarray} |
\end{eqnarray} |
283 |
|
|
290 |
speed of $ | \vec{u} | = 2 ms^{-1}$ |
speed of $ | \vec{u} | = 2 ms^{-1}$ |
291 |
|
|
292 |
\begin{eqnarray} |
\begin{eqnarray} |
293 |
\label{EQ:eg-global-cfl_stability} |
\label{eq:eg-global-cfl_stability} |
294 |
S_{a} = \frac{| \vec{u} | \delta t_{v}}{ \Delta x} |
S_{a} = \frac{| \vec{u} | \delta t_{v}}{ \Delta x} |
295 |
\end{eqnarray} |
\end{eqnarray} |
296 |
|
|
303 |
\cite{adcroft:95} |
\cite{adcroft:95} |
304 |
|
|
305 |
\begin{eqnarray} |
\begin{eqnarray} |
306 |
\label{EQ:eg-global-gfl_stability} |
\label{eq:eg-global-gfl_stability} |
307 |
S_{c} = \frac{c_{g} \delta t_{v}}{ \Delta x} |
S_{c} = \frac{c_{g} \delta t_{v}}{ \Delta x} |
308 |
\end{eqnarray} |
\end{eqnarray} |
309 |
|
|
311 |
stability limit of 0.5. |
stability limit of 0.5. |
312 |
|
|
313 |
\subsection{Experiment Configuration} |
\subsection{Experiment Configuration} |
314 |
\label{www:tutorials} |
%\label{www:tutorials} |
315 |
\label{SEC:eg-global-clim_ocn_examp_exp_config} |
\label{sec:eg-global-clim_ocn_examp_exp_config} |
316 |
|
|
317 |
The model configuration for this experiment resides under the |
The model configuration for this experiment resides under the |
318 |
directory {\it tutorial\_examples/global\_ocean\_circulation/}. |
directory {\it tutorial\_examples/global\_ocean\_circulation/}. |
338 |
to these files associated with this experiment. |
to these files associated with this experiment. |
339 |
|
|
340 |
\subsubsection{Driving Datasets} |
\subsubsection{Driving Datasets} |
341 |
\label{www:tutorials} |
%\label{www:tutorials} |
342 |
|
|
343 |
Figures (\ref{FIG:sim_config_tclim}-\ref{FIG:sim_config_empmr}) show the |
Figures ({\it --- missing figures ---}) |
344 |
relaxation temperature ($\theta^{\ast}$) and salinity ($S^{\ast}$) fields, |
%(\ref{fig:sim_config_tclim}-\ref{fig:sim_config_empmr}) |
345 |
the wind stress components ($\tau_x$ and $\tau_y$), the heat flux ($Q$) |
show the relaxation temperature ($\theta^{\ast}$) and salinity ($S^{\ast}$) |
346 |
|
fields, the wind stress components ($\tau_x$ and $\tau_y$), the heat flux ($Q$) |
347 |
and the net fresh water flux (${\cal E} - {\cal P} - {\cal R}$) used |
and the net fresh water flux (${\cal E} - {\cal P} - {\cal R}$) used |
348 |
in equations \ref{EQ:global_forcing_fu}-\ref{EQ:global_forcing_fs}. The figures |
in equations |
349 |
also indicate the lateral extent and coastline used in the experiment. |
(\ref{eq:eg-global-global_forcing_fu}-\ref{eq:eg-global-global_forcing_fs}). |
350 |
Figure ({\ref{FIG:model_bathymetry}) shows the depth contours of the model |
The figures also indicate the lateral extent and coastline used in the |
351 |
domain. |
experiment. Figure ({\it --- missing figure --- }) %ref{fig:model_bathymetry}) |
352 |
|
shows the depth contours of the model domain. |
353 |
|
|
354 |
\subsubsection{File {\it input/data}} |
\subsubsection{File {\it input/data}} |
355 |
\label{www:tutorials} |
%\label{www:tutorials} |
356 |
|
|
357 |
This file, reproduced completely below, specifies the main parameters |
This file, reproduced completely below, specifies the main parameters |
358 |
for the experiment. The parameters that are significant for this configuration |
for the experiment. The parameters that are significant for this configuration |
524 |
\end{verbatim} |
\end{verbatim} |
525 |
Sets the tolerance which the two-dimensional, conjugate |
Sets the tolerance which the two-dimensional, conjugate |
526 |
gradient solver will use to test for convergence in equation |
gradient solver will use to test for convergence in equation |
527 |
\ref{EQ:congrad_2d_resid} to $1 \times 10^{-13}$. |
%- note: Description of Conjugate gradient method (& related params) is missing |
528 |
Solver will iterate until |
% in the mean time, substitute this eq ref: |
529 |
tolerance falls below this value or until the maximum number of |
\ref{eq:elliptic-backward-free-surface} %\ref{eq:congrad_2d_resid} |
530 |
solver iterations is reached.\\ |
to $1 \times 10^{-13}$. |
531 |
|
Solver will iterate until tolerance falls below this value or until the |
532 |
|
maximum number of solver iterations is reached.\\ |
533 |
\fbox{ |
\fbox{ |
534 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
535 |
{\it S/R CG2D}~({\it cg2d.F}) |
{\it S/R CG2D}~({\it cg2d.F}) |
568 |
\end{verbatim} |
\end{verbatim} |
569 |
Sets the timestep $\delta t_{v}$ used in the momentum equations to |
Sets the timestep $\delta t_{v}$ used in the momentum equations to |
570 |
$20~{\rm mins}$. |
$20~{\rm mins}$. |
571 |
See section \ref{SEC:mom_time_stepping}. |
%- note: Distord Physics (using different time-steps) is not described |
572 |
|
% in the mean time, put this section ref: |
573 |
|
See section \ref{sec:time_stepping}. %\ref{sec:mom_time_stepping}. |
574 |
|
|
575 |
\fbox{ |
\fbox{ |
576 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
582 |
\begin{verbatim} |
\begin{verbatim} |
583 |
tauCD=321428., |
tauCD=321428., |
584 |
\end{verbatim} |
\end{verbatim} |
585 |
Sets the D-grid to C-grid coupling time scale $\tau_{CD}$ used in the momentum equations. |
Sets the D-grid to C-grid coupling time scale $\tau_{CD}$ |
586 |
See section \ref{SEC:cd_scheme}. |
used in the momentum equations. |
587 |
|
%- note: description of CD-scheme pkg (and related params) is missing; |
588 |
|
% in the mean time, comment out this ref. |
589 |
|
%See section \ref{sec:cd_scheme}. |
590 |
|
|
591 |
\fbox{ |
\fbox{ |
592 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
601 |
\end{verbatim} |
\end{verbatim} |
602 |
Sets the default timestep, $\delta t_{\theta}$, for tracer equations to |
Sets the default timestep, $\delta t_{\theta}$, for tracer equations to |
603 |
$30~{\rm hours}$. |
$30~{\rm hours}$. |
604 |
See section \ref{SEC:tracer_time_stepping}. |
%- note: Distord Physics (using different time-steps) is not described |
605 |
|
% in the mean time, put this section ref: |
606 |
|
See section \ref{sec:time_stepping}. %\ref{sec:tracer_time_stepping}. |
607 |
|
|
608 |
\fbox{ |
\fbox{ |
609 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
651 |
\end{small} |
\end{small} |
652 |
|
|
653 |
\subsubsection{File {\it input/data.pkg}} |
\subsubsection{File {\it input/data.pkg}} |
654 |
\label{www:tutorials} |
%\label{www:tutorials} |
655 |
|
|
656 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
657 |
customisations for this experiment. |
customisations for this experiment. |
658 |
|
|
659 |
\subsubsection{File {\it input/eedata}} |
\subsubsection{File {\it input/eedata}} |
660 |
\label{www:tutorials} |
%\label{www:tutorials} |
661 |
|
|
662 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
663 |
customisations for this experiment. |
customisations for this experiment. |
664 |
|
|
665 |
\subsubsection{File {\it input/windx.sin\_y}} |
\subsubsection{File {\it input/windx.sin\_y}} |
666 |
\label{www:tutorials} |
%\label{www:tutorials} |
667 |
|
|
668 |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
669 |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$. |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$. |
674 |
code for creating the {\it input/windx.sin\_y} file. |
code for creating the {\it input/windx.sin\_y} file. |
675 |
|
|
676 |
\subsubsection{File {\it input/topog.box}} |
\subsubsection{File {\it input/topog.box}} |
677 |
\label{www:tutorials} |
%\label{www:tutorials} |
678 |
|
|
679 |
|
|
680 |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
686 |
code for creating the {\it input/topog.box} file. |
code for creating the {\it input/topog.box} file. |
687 |
|
|
688 |
\subsubsection{File {\it code/SIZE.h}} |
\subsubsection{File {\it code/SIZE.h}} |
689 |
\label{www:tutorials} |
%\label{www:tutorials} |
690 |
|
|
691 |
Two lines are customized in this file for the current experiment |
Two lines are customized in this file for the current experiment |
692 |
|
|
713 |
\end{small} |
\end{small} |
714 |
|
|
715 |
\subsubsection{File {\it code/CPP\_OPTIONS.h}} |
\subsubsection{File {\it code/CPP\_OPTIONS.h}} |
716 |
\label{www:tutorials} |
%\label{www:tutorials} |
717 |
|
|
718 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
719 |
customisations for this experiment. |
customisations for this experiment. |
720 |
|
|
721 |
|
|
722 |
\subsubsection{File {\it code/CPP\_EEOPTIONS.h}} |
\subsubsection{File {\it code/CPP\_EEOPTIONS.h}} |
723 |
\label{www:tutorials} |
%\label{www:tutorials} |
724 |
|
|
725 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
726 |
customisations for this experiment. |
customisations for this experiment. |
727 |
|
|
728 |
\subsubsection{Other Files } |
\subsubsection{Other Files } |
729 |
\label{www:tutorials} |
%\label{www:tutorials} |
730 |
|
|
731 |
Other files relevant to this experiment are |
Other files relevant to this experiment are |
732 |
\begin{itemize} |
\begin{itemize} |