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\section{Introduction} |
\section{Introduction} |
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\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:innovations --> |
<!-- CMIREDIR:innovations: --> |
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\end{rawhtml} |
\end{rawhtml} |
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\end{itemize} |
\end{itemize} |
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| 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}: |
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| 93 |
\begin{verbatim} |
\begin{verbatim} |
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Hill, C. and J. Marshall, (1995) |
Hill, C. and J. Marshall, (1995) |
| 142 |
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| 143 |
\section{Illustrations of the model in action} |
\section{Illustrations of the model in action} |
| 144 |
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| 145 |
The MITgcm has been designed and used to model a wide range of phenomena, |
MITgcm has been designed and used to model a wide range of phenomena, |
| 146 |
from convection on the scale of meters in the ocean to the global pattern of |
from convection on the scale of meters in the ocean to the global pattern of |
| 147 |
atmospheric winds - see figure \ref{fig:all-scales}. To give a flavor of the |
atmospheric winds - see figure \ref{fig:all-scales}. To give a flavor of the |
| 148 |
kinds of problems the model has been used to study, we briefly describe some |
kinds of problems the model has been used to study, we briefly describe some |
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| 156 |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
| 157 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:atmospheric_example --> |
<!-- CMIREDIR:atmospheric_example: --> |
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\end{rawhtml} |
\end{rawhtml} |
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\subsection{Ocean gyres} |
\subsection{Ocean gyres} |
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\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:oceanic_example --> |
<!-- CMIREDIR:oceanic_example: --> |
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\end{rawhtml} |
\end{rawhtml} |
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\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:ocean_gyres --> |
<!-- CMIREDIR:ocean_gyres: --> |
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\end{rawhtml} |
\end{rawhtml} |
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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 |
| 228 |
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| 229 |
\subsection{Global ocean circulation} |
\subsection{Global ocean circulation} |
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\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:global_ocean_circulation --> |
<!-- CMIREDIR:global_ocean_circulation: --> |
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\end{rawhtml} |
\end{rawhtml} |
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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 |
| 249 |
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| 250 |
\subsection{Convection and mixing over topography} |
\subsection{Convection and mixing over topography} |
| 251 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:mixing_over_topography --> |
<!-- CMIREDIR:mixing_over_topography: --> |
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\end{rawhtml} |
\end{rawhtml} |
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\subsection{Boundary forced internal waves} |
\subsection{Boundary forced internal waves} |
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\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:boundary_forced_internal_waves --> |
<!-- CMIREDIR:boundary_forced_internal_waves: --> |
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\end{rawhtml} |
\end{rawhtml} |
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The unique ability of MITgcm to treat non-hydrostatic dynamics in the |
The unique ability of MITgcm to treat non-hydrostatic dynamics in the |
| 294 |
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| 295 |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
| 296 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:parameter_sensitivity --> |
<!-- CMIREDIR:parameter_sensitivity: --> |
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\end{rawhtml} |
\end{rawhtml} |
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| 300 |
Forward and tangent linear counterparts of MITgcm are supported using an |
Forward and tangent linear counterparts of MITgcm are supported using an |
| 317 |
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| 318 |
\subsection{Global state estimation of the ocean} |
\subsection{Global state estimation of the ocean} |
| 319 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:global_state_estimation --> |
<!-- CMIREDIR:global_state_estimation: --> |
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\end{rawhtml} |
\end{rawhtml} |
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| 339 |
\subsection{Ocean biogeochemical cycles} |
\subsection{Ocean biogeochemical cycles} |
| 340 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:ocean_biogeo_cycles --> |
<!-- CMIREDIR:ocean_biogeo_cycles: --> |
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\end{rawhtml} |
\end{rawhtml} |
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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 |
| 356 |
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| 357 |
\subsection{Simulations of laboratory experiments} |
\subsection{Simulations of laboratory experiments} |
| 358 |
\begin{rawhtml} |
\begin{rawhtml} |
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<!-- CMIREDIR:classroom_exp --> |
<!-- CMIREDIR:classroom_exp: --> |
| 360 |
\end{rawhtml} |
\end{rawhtml} |
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| 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 |
| 377 |
|
|
| 378 |
\section{Continuous equations in `r' coordinates} |
\section{Continuous equations in `r' coordinates} |
| 379 |
\begin{rawhtml} |
\begin{rawhtml} |
| 380 |
<!-- CMIREDIR:z-p_isomorphism --> |
<!-- CMIREDIR:z-p_isomorphism: --> |
| 381 |
\end{rawhtml} |
\end{rawhtml} |
| 382 |
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| 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 |
| 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{ |
| 611 |
atmosphere)} \label{eq:moving-bc-atmos} |
atmosphere)} \label{eq:moving-bc-atmos} |
| 612 |
\end{eqnarray} |
\end{eqnarray} |
| 613 |
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|
| 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 |
|
|
| 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} |
\begin{rawhtml} |
| 661 |
<!-- CMIREDIR:non_hydrostatic --> |
<!-- CMIREDIR:non_hydrostatic: --> |
| 662 |
\end{rawhtml} |
\end{rawhtml} |
| 663 |
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| 664 |
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| 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 |
| 770 |
|
|
| 771 |
\subsubsection{Shallow atmosphere approximation} |
\subsubsection{Shallow atmosphere approximation} |
| 772 |
|
|
| 773 |
Most models are based on the `hydrostatic primitive equations' (HPE's) in |
Most models are based on the `hydrostatic primitive equations' (HPE's) |
| 774 |
which the vertical momentum equation is reduced to a statement of |
in which the vertical momentum equation is reduced to a statement of |
| 775 |
hydrostatic balance and the `traditional approximation' is made in which the |
hydrostatic balance and the `traditional approximation' is made in |
| 776 |
Coriolis force is treated approximately and the shallow atmosphere |
which the Coriolis force is treated approximately and the shallow |
| 777 |
approximation is made.\ The MITgcm need not make the `traditional |
atmosphere approximation is made. MITgcm need not make the |
| 778 |
approximation'. To be able to support consistent non-hydrostatic forms the |
`traditional approximation'. To be able to support consistent |
| 779 |
shallow atmosphere approximation can be relaxed - when dividing through by $ |
non-hydrostatic forms the shallow atmosphere approximation can be |
| 780 |
r $ in, for example, (\ref{eq:gu-speherical}), we do not replace $r$ by $a$, |
relaxed - when dividing through by $ r $ in, for example, |
| 781 |
the radius of the earth. |
(\ref{eq:gu-speherical}), we do not replace $r$ by $a$, the radius of |
| 782 |
|
the earth. |
| 783 |
|
|
| 784 |
\subsubsection{Hydrostatic and quasi-hydrostatic forms} |
\subsubsection{Hydrostatic and quasi-hydrostatic forms} |
| 785 |
\label{sec:hydrostatic_and_quasi-hydrostatic_forms} |
\label{sec:hydrostatic_and_quasi-hydrostatic_forms} |
| 816 |
|
|
| 817 |
\subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms} |
\subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms} |
| 818 |
|
|
| 819 |
The MIT model presently supports a full non-hydrostatic ocean isomorph, but |
MITgcm presently supports a full non-hydrostatic ocean isomorph, but |
| 820 |
only a quasi-non-hydrostatic atmospheric isomorph. |
only a quasi-non-hydrostatic atmospheric isomorph. |
| 821 |
|
|
| 822 |
\paragraph{Non-hydrostatic Ocean} |
\paragraph{Non-hydrostatic Ocean} |
| 1101 |
|
|
| 1102 |
\subsection{Vector invariant form} |
\subsection{Vector invariant form} |
| 1103 |
|
|
| 1104 |
For some purposes it is advantageous to write momentum advection in eq(\ref |
For some purposes it is advantageous to write momentum advection in |
| 1105 |
{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 |
| 1106 |
|
(so-called) `vector invariant' form: |
| 1107 |
|
|
| 1108 |
\begin{equation} |
\begin{equation} |
| 1109 |
\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} |
| 1214 |
surface ($\phi $ is imposed and $\omega \neq 0$). |
surface ($\phi $ is imposed and $\omega \neq 0$). |
| 1215 |
|
|
| 1216 |
\subsubsection{Splitting the geo-potential} |
\subsubsection{Splitting the geo-potential} |
| 1217 |
|
\label{sec:hpe-p-geo-potential-split} |
| 1218 |
|
|
| 1219 |
For the purposes of initialization and reducing round-off errors, the model |
For the purposes of initialization and reducing round-off errors, the model |
| 1220 |
deals with perturbations from reference (or ``standard'') profiles. For |
deals with perturbations from reference (or ``standard'') profiles. For |
| 1244 |
The final form of the HPE's in p coordinates is then: |
The final form of the HPE's in p coordinates is then: |
| 1245 |
\begin{eqnarray} |
\begin{eqnarray} |
| 1246 |
\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}} |
| 1247 |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\ |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} |
| 1248 |
|
\label{eq:atmos-prime} \\ |
| 1249 |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
| 1250 |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
| 1251 |
\partial p} &=&0 \\ |
\partial p} &=&0 \\ |
| 1291 |
_{\theta ,S}\frac{Dp}{Dt} \label{EOSexpansion} |
_{\theta ,S}\frac{Dp}{Dt} \label{EOSexpansion} |
| 1292 |
\end{equation} |
\end{equation} |
| 1293 |
|
|
| 1294 |
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 |
| 1295 |
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 |
| 1296 |
|
\ref{eq-zns-cont} gives: |
| 1297 |
\begin{equation} |
\begin{equation} |
| 1298 |
\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{ |
| 1299 |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |