48 |
also presented. |
also presented. |
49 |
|
|
50 |
\section{Introduction} |
\section{Introduction} |
51 |
|
\begin{rawhtml} |
52 |
|
<!-- CMIREDIR:innovations: --> |
53 |
|
\end{rawhtml} |
54 |
|
|
55 |
|
|
56 |
MITgcm has a number of novel aspects: |
MITgcm has a number of novel aspects: |
57 |
|
|
88 |
\end{itemize} |
\end{itemize} |
89 |
|
|
90 |
Key publications reporting on and charting the development of the model are |
Key publications reporting on and charting the development of the model are |
91 |
\cite{hill:95,marshall:97a,marshall:97b,adcroft:97,marshall:98,adcroft:99,hill:99,maro-eta:99}: |
\cite{hill:95,marshall:97a,marshall:97b,adcroft:97,marshall:98,adcroft:99,hill:99,maro-eta:99,adcroft:04a,adcroft:04b,marshall:04}: |
92 |
|
|
93 |
\begin{verbatim} |
\begin{verbatim} |
94 |
Hill, C. and J. Marshall, (1995) |
Hill, C. and J. Marshall, (1995) |
154 |
described in detail in the documentation. |
described in detail in the documentation. |
155 |
|
|
156 |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
157 |
|
\begin{rawhtml} |
158 |
|
<!-- CMIREDIR:atmospheric_example: --> |
159 |
|
\end{rawhtml} |
160 |
|
|
161 |
|
|
162 |
|
|
163 |
A novel feature of MITgcm is its ability to simulate, using one basic algorithm, |
A novel feature of MITgcm is its ability to simulate, using one basic algorithm, |
164 |
both atmospheric and oceanographic flows at both small and large scales. |
both atmospheric and oceanographic flows at both small and large scales. |
195 |
%% CNHend |
%% CNHend |
196 |
|
|
197 |
\subsection{Ocean gyres} |
\subsection{Ocean gyres} |
198 |
|
\begin{rawhtml} |
199 |
|
<!-- CMIREDIR:oceanic_example: --> |
200 |
|
\end{rawhtml} |
201 |
|
\begin{rawhtml} |
202 |
|
<!-- CMIREDIR:ocean_gyres: --> |
203 |
|
\end{rawhtml} |
204 |
|
|
205 |
Baroclinic instability is a ubiquitous process in the ocean, as well as the |
Baroclinic instability is a ubiquitous process in the ocean, as well as the |
206 |
atmosphere. Ocean eddies play an important role in modifying the |
atmosphere. Ocean eddies play an important role in modifying the |
227 |
|
|
228 |
|
|
229 |
\subsection{Global ocean circulation} |
\subsection{Global ocean circulation} |
230 |
|
\begin{rawhtml} |
231 |
|
<!-- CMIREDIR:global_ocean_circulation: --> |
232 |
|
\end{rawhtml} |
233 |
|
|
234 |
Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean currents at |
Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean currents at |
235 |
the surface of a 4$^{\circ }$ |
the surface of a 4$^{\circ }$ |
248 |
%%CNHend |
%%CNHend |
249 |
|
|
250 |
\subsection{Convection and mixing over topography} |
\subsection{Convection and mixing over topography} |
251 |
|
\begin{rawhtml} |
252 |
|
<!-- CMIREDIR:mixing_over_topography: --> |
253 |
|
\end{rawhtml} |
254 |
|
|
255 |
|
|
256 |
Dense plumes generated by localized cooling on the continental shelf of the |
Dense plumes generated by localized cooling on the continental shelf of the |
257 |
ocean may be influenced by rotation when the deformation radius is smaller |
ocean may be influenced by rotation when the deformation radius is smaller |
271 |
%%CNHend |
%%CNHend |
272 |
|
|
273 |
\subsection{Boundary forced internal waves} |
\subsection{Boundary forced internal waves} |
274 |
|
\begin{rawhtml} |
275 |
|
<!-- CMIREDIR:boundary_forced_internal_waves: --> |
276 |
|
\end{rawhtml} |
277 |
|
|
278 |
The unique ability of MITgcm to treat non-hydrostatic dynamics in the |
The unique ability of MITgcm to treat non-hydrostatic dynamics in the |
279 |
presence of complex geometry makes it an ideal tool to study internal wave |
presence of complex geometry makes it an ideal tool to study internal wave |
293 |
%%CNHend |
%%CNHend |
294 |
|
|
295 |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
296 |
|
\begin{rawhtml} |
297 |
|
<!-- CMIREDIR:parameter_sensitivity: --> |
298 |
|
\end{rawhtml} |
299 |
|
|
300 |
Forward and tangent linear counterparts of MITgcm are supported using an |
Forward and tangent linear counterparts of MITgcm are supported using an |
301 |
`automatic adjoint compiler'. These can be used in parameter sensitivity and |
`automatic adjoint compiler'. These can be used in parameter sensitivity and |
316 |
%%CNHend |
%%CNHend |
317 |
|
|
318 |
\subsection{Global state estimation of the ocean} |
\subsection{Global state estimation of the ocean} |
319 |
|
\begin{rawhtml} |
320 |
|
<!-- CMIREDIR:global_state_estimation: --> |
321 |
|
\end{rawhtml} |
322 |
|
|
323 |
|
|
324 |
An important application of MITgcm is in state estimation of the global |
An important application of MITgcm is in state estimation of the global |
325 |
ocean circulation. An appropriately defined `cost function', which measures |
ocean circulation. An appropriately defined `cost function', which measures |
337 |
%% CNHend |
%% CNHend |
338 |
|
|
339 |
\subsection{Ocean biogeochemical cycles} |
\subsection{Ocean biogeochemical cycles} |
340 |
|
\begin{rawhtml} |
341 |
|
<!-- CMIREDIR:ocean_biogeo_cycles: --> |
342 |
|
\end{rawhtml} |
343 |
|
|
344 |
MITgcm is being used to study global biogeochemical cycles in the ocean. For |
MITgcm is being used to study global biogeochemical cycles in the ocean. For |
345 |
example one can study the effects of interannual changes in meteorological |
example one can study the effects of interannual changes in meteorological |
355 |
%%CNHend |
%%CNHend |
356 |
|
|
357 |
\subsection{Simulations of laboratory experiments} |
\subsection{Simulations of laboratory experiments} |
358 |
|
\begin{rawhtml} |
359 |
|
<!-- CMIREDIR:classroom_exp: --> |
360 |
|
\end{rawhtml} |
361 |
|
|
362 |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
363 |
laboratory experiment inquiring in to the dynamics of the Antarctic Circumpolar Current (ACC). An |
laboratory experiment inquiring into the dynamics of the Antarctic Circumpolar Current (ACC). An |
364 |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
365 |
free surface by a rotating heated disk. The combined action of mechanical |
free surface by a rotating heated disk. The combined action of mechanical |
366 |
and thermal forcing creates a lens of fluid which becomes baroclinically |
and thermal forcing creates a lens of fluid which becomes baroclinically |
376 |
% $Name$ |
% $Name$ |
377 |
|
|
378 |
\section{Continuous equations in `r' coordinates} |
\section{Continuous equations in `r' coordinates} |
379 |
|
\begin{rawhtml} |
380 |
|
<!-- CMIREDIR:z-p_isomorphism: --> |
381 |
|
\end{rawhtml} |
382 |
|
|
383 |
To render atmosphere and ocean models from one dynamical core we exploit |
To render atmosphere and ocean models from one dynamical core we exploit |
384 |
`isomorphisms' between equation sets that govern the evolution of the |
`isomorphisms' between equation sets that govern the evolution of the |
387 |
and encoded. The model variables have different interpretations depending on |
and encoded. The model variables have different interpretations depending on |
388 |
whether the atmosphere or ocean is being studied. Thus, for example, the |
whether the atmosphere or ocean is being studied. Thus, for example, the |
389 |
vertical coordinate `$r$' is interpreted as pressure, $p$, if we are |
vertical coordinate `$r$' is interpreted as pressure, $p$, if we are |
390 |
modeling the atmosphere (left hand side of figure \ref{fig:isomorphic-equations}) |
modeling the atmosphere (right hand side of figure \ref{fig:isomorphic-equations}) |
391 |
and height, $z$, if we are modeling the ocean (right hand side of figure |
and height, $z$, if we are modeling the ocean (left hand side of figure |
392 |
\ref{fig:isomorphic-equations}). |
\ref{fig:isomorphic-equations}). |
393 |
|
|
394 |
%%CNHbegin |
%%CNHbegin |
409 |
\input{part1/vertcoord_figure.tex} |
\input{part1/vertcoord_figure.tex} |
410 |
%%CNHend |
%%CNHend |
411 |
|
|
412 |
\begin{equation*} |
\begin{equation} |
413 |
\frac{D\vec{\mathbf{v}_{h}}}{Dt}+\left( 2\vec{\Omega}\times \vec{\mathbf{v}} |
\frac{D\vec{\mathbf{v}_{h}}}{Dt}+\left( 2\vec{\Omega}\times \vec{\mathbf{v}} |
414 |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
415 |
\text{ horizontal mtm} \label{eq:horizontal_mtm} |
\text{ horizontal mtm} \label{eq:horizontal_mtm} |
416 |
\end{equation*} |
\end{equation} |
417 |
|
|
418 |
\begin{equation} |
\begin{equation} |
419 |
\frac{D\dot{r}}{Dt}+\widehat{k}\cdot \left( 2\vec{\Omega}\times \vec{\mathbf{ |
\frac{D\dot{r}}{Dt}+\widehat{k}\cdot \left( 2\vec{\Omega}\times \vec{\mathbf{ |
512 |
at fixed and moving $r$ surfaces we set (see figure \ref{fig:zandp-vert-coord}): |
at fixed and moving $r$ surfaces we set (see figure \ref{fig:zandp-vert-coord}): |
513 |
|
|
514 |
\begin{equation} |
\begin{equation} |
515 |
\dot{r}=0atr=R_{fixed}(x,y)\text{ (ocean bottom, top of the atmosphere)} |
\dot{r}=0 \text{\ at\ } r=R_{fixed}(x,y)\text{ (ocean bottom, top of the atmosphere)} |
516 |
\label{eq:fixedbc} |
\label{eq:fixedbc} |
517 |
\end{equation} |
\end{equation} |
518 |
|
|
519 |
\begin{equation} |
\begin{equation} |
520 |
\dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \ |
\dot{r}=\frac{Dr}{Dt} \text{\ at\ } r=R_{moving}\text{ \ |
521 |
(ocean surface,bottom of the atmosphere)} \label{eq:movingbc} |
(ocean surface,bottom of the atmosphere)} \label{eq:movingbc} |
522 |
\end{equation} |
\end{equation} |
523 |
|
|
611 |
atmosphere)} \label{eq:moving-bc-atmos} |
atmosphere)} \label{eq:moving-bc-atmos} |
612 |
\end{eqnarray} |
\end{eqnarray} |
613 |
|
|
614 |
Then the (hydrostatic form of) equations (\ref{eq:horizontal_mtm}-\ref{eq:humidity_salt}) |
Then the (hydrostatic form of) equations |
615 |
yields a consistent set of atmospheric equations which, for convenience, are written out in $p$ |
(\ref{eq:horizontal_mtm}-\ref{eq:humidity_salt}) yields a consistent |
616 |
coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}). |
set of atmospheric equations which, for convenience, are written out |
617 |
|
in $p$ coordinates in Appendix Atmosphere - see |
618 |
|
eqs(\ref{eq:atmos-prime}). |
619 |
|
|
620 |
\subsection{Ocean} |
\subsection{Ocean} |
621 |
|
|
657 |
|
|
658 |
\subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and |
\subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and |
659 |
Non-hydrostatic forms} |
Non-hydrostatic forms} |
660 |
|
\begin{rawhtml} |
661 |
|
<!-- CMIREDIR:non_hydrostatic: --> |
662 |
|
\end{rawhtml} |
663 |
|
|
664 |
|
|
665 |
Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms: |
Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms: |
666 |
|
|
668 |
\phi (x,y,r)=\phi _{s}(x,y)+\phi _{hyd}(x,y,r)+\phi _{nh}(x,y,r) |
\phi (x,y,r)=\phi _{s}(x,y)+\phi _{hyd}(x,y,r)+\phi _{nh}(x,y,r) |
669 |
\label{eq:phi-split} |
\label{eq:phi-split} |
670 |
\end{equation} |
\end{equation} |
671 |
and write eq(\ref{eq:incompressible}) in the form: |
%and write eq(\ref{eq:incompressible}) in the form: |
672 |
|
% ^- this eq is missing (jmc) ; replaced with: |
673 |
|
and write eq( \ref{eq:horizontal_mtm}) in the form: |
674 |
|
|
675 |
\begin{equation} |
\begin{equation} |
676 |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
1100 |
|
|
1101 |
\subsection{Vector invariant form} |
\subsection{Vector invariant form} |
1102 |
|
|
1103 |
For some purposes it is advantageous to write momentum advection in eq(\ref |
For some purposes it is advantageous to write momentum advection in |
1104 |
{eq:horizontal_mtm}) and (\ref{eq:vertical_mtm}) in the (so-called) `vector invariant' form: |
eq(\ref {eq:horizontal_mtm}) and (\ref{eq:vertical_mtm}) in the |
1105 |
|
(so-called) `vector invariant' form: |
1106 |
|
|
1107 |
\begin{equation} |
\begin{equation} |
1108 |
\frac{D\vec{\mathbf{v}}}{Dt}=\frac{\partial \vec{\mathbf{v}}}{\partial t} |
\frac{D\vec{\mathbf{v}}}{Dt}=\frac{\partial \vec{\mathbf{v}}}{\partial t} |
1213 |
surface ($\phi $ is imposed and $\omega \neq 0$). |
surface ($\phi $ is imposed and $\omega \neq 0$). |
1214 |
|
|
1215 |
\subsubsection{Splitting the geo-potential} |
\subsubsection{Splitting the geo-potential} |
1216 |
|
\label{sec:hpe-p-geo-potential-split} |
1217 |
|
|
1218 |
For the purposes of initialization and reducing round-off errors, the model |
For the purposes of initialization and reducing round-off errors, the model |
1219 |
deals with perturbations from reference (or ``standard'') profiles. For |
deals with perturbations from reference (or ``standard'') profiles. For |
1243 |
The final form of the HPE's in p coordinates is then: |
The final form of the HPE's in p coordinates is then: |
1244 |
\begin{eqnarray} |
\begin{eqnarray} |
1245 |
\frac{D\vec{\mathbf{v}}_{h}}{Dt}+f\hat{\mathbf{k}}\times \vec{\mathbf{v}} |
\frac{D\vec{\mathbf{v}}_{h}}{Dt}+f\hat{\mathbf{k}}\times \vec{\mathbf{v}} |
1246 |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\ |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} |
1247 |
|
\label{eq:atmos-prime} \\ |
1248 |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
1249 |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
1250 |
\partial p} &=&0 \\ |
\partial p} &=&0 \\ |
1290 |
_{\theta ,S}\frac{Dp}{Dt} \label{EOSexpansion} |
_{\theta ,S}\frac{Dp}{Dt} \label{EOSexpansion} |
1291 |
\end{equation} |
\end{equation} |
1292 |
|
|
1293 |
Note that $\frac{\partial \rho }{\partial p}=\frac{1}{c_{s}^{2}}$ is the |
Note that $\frac{\partial \rho }{\partial p}=\frac{1}{c_{s}^{2}}$ is |
1294 |
reciprocal of the sound speed ($c_{s}$) squared. Substituting into \ref{eq-zns-cont} gives: |
the reciprocal of the sound speed ($c_{s}$) squared. Substituting into |
1295 |
|
\ref{eq-zns-cont} gives: |
1296 |
\begin{equation} |
\begin{equation} |
1297 |
\frac{1}{\rho c_{s}^{2}}\frac{Dp}{Dt}+\mathbf{\nabla }_{z}\cdot \vec{\mathbf{ |
\frac{1}{\rho c_{s}^{2}}\frac{Dp}{Dt}+\mathbf{\nabla }_{z}\cdot \vec{\mathbf{ |
1298 |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |