83 |
computational platforms. |
computational platforms. |
84 |
\end{itemize} |
\end{itemize} |
85 |
|
|
86 |
Key publications reporting on and charting the development of the model are |
Key publications reporting on and charting the development of the model are: |
87 |
listed in an Appendix. |
|
88 |
|
\begin{verbatim} |
89 |
|
|
90 |
|
Hill, C. and J. Marshall, (1995) |
91 |
|
Application of a Parallel Navier-Stokes Model to Ocean Circulation in |
92 |
|
Parallel Computational Fluid Dynamics |
93 |
|
In Proceedings of Parallel Computational Fluid Dynamics: Implementations |
94 |
|
and Results Using Parallel Computers, 545-552. |
95 |
|
Elsevier Science B.V.: New York |
96 |
|
|
97 |
|
Marshall, J., C. Hill, L. Perelman, and A. Adcroft, (1997) |
98 |
|
Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling, |
99 |
|
J. Geophysical Res., 102(C3), 5733-5752. |
100 |
|
|
101 |
|
Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, (1997) |
102 |
|
A finite-volume, incompressible Navier Stokes model for studies of the ocean |
103 |
|
on parallel computers, |
104 |
|
J. Geophysical Res., 102(C3), 5753-5766. |
105 |
|
|
106 |
|
Adcroft, A.J., Hill, C.N. and J. Marshall, (1997) |
107 |
|
Representation of topography by shaved cells in a height coordinate ocean |
108 |
|
model |
109 |
|
Mon Wea Rev, vol 125, 2293-2315 |
110 |
|
|
111 |
|
Marshall, J., Jones, H. and C. Hill, (1998) |
112 |
|
Efficient ocean modeling using non-hydrostatic algorithms |
113 |
|
Journal of Marine Systems, 18, 115-134 |
114 |
|
|
115 |
|
Adcroft, A., Hill C. and J. Marshall: (1999) |
116 |
|
A new treatment of the Coriolis terms in C-grid models at both high and low |
117 |
|
resolutions, |
118 |
|
Mon. Wea. Rev. Vol 127, pages 1928-1936 |
119 |
|
|
120 |
|
Hill, C, Adcroft,A., Jamous,D., and J. Marshall, (1999) |
121 |
|
A Strategy for Terascale Climate Modeling. |
122 |
|
In Proceedings of the Eight ECMWF Workshop on the Use of Parallel Processors |
123 |
|
in Meteorology |
124 |
|
|
125 |
|
Marotzke, J, Giering,R., Zhang, K.Q., Stammer,D., Hill,C., and T.Lee, (1999) |
126 |
|
Construction of the adjoint MIT ocean general circulation model and |
127 |
|
application to Atlantic heat transport variability |
128 |
|
J. Geophysical Res., 104(C12), 29,529-29,547. |
129 |
|
|
130 |
|
|
131 |
|
\end{verbatim} |
132 |
|
|
133 |
We begin by briefly showing some of the results of the model in action to |
We begin by briefly showing some of the results of the model in action to |
134 |
give a feel for the wide range of problems that can be addressed using it. |
give a feel for the wide range of problems that can be addressed using it. |
146 |
numerical algorithm and implementation that lie behind these calculations is |
numerical algorithm and implementation that lie behind these calculations is |
147 |
given later. Indeed many of the illustrative examples shown below can be |
given later. Indeed many of the illustrative examples shown below can be |
148 |
easily reproduced: simply download the model (the minimum you need is a PC |
easily reproduced: simply download the model (the minimum you need is a PC |
149 |
running linux, together with a FORTRAN\ 77 compiler) and follow the examples |
running Linux, together with a FORTRAN\ 77 compiler) and follow the examples |
150 |
described in detail in the documentation. |
described in detail in the documentation. |
151 |
|
|
152 |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
170 |
%% CNHend |
%% CNHend |
171 |
|
|
172 |
As described in Adcroft (2001), a `cubed sphere' is used to discretize the |
As described in Adcroft (2001), a `cubed sphere' is used to discretize the |
173 |
globe permitting a uniform gridding and obviated the need to Fourier filter. |
globe permitting a uniform griding and obviated the need to Fourier filter. |
174 |
The `vector-invariant' form of MITgcm supports any orthogonal curvilinear |
The `vector-invariant' form of MITgcm supports any orthogonal curvilinear |
175 |
grid, of which the cubed sphere is just one of many choices. |
grid, of which the cubed sphere is just one of many choices. |
176 |
|
|
207 |
visible. |
visible. |
208 |
|
|
209 |
%% CNHbegin |
%% CNHbegin |
210 |
\input{part1/ocean_gyres_figure} |
\input{part1/atl6_figure} |
211 |
%% CNHend |
%% CNHend |
212 |
|
|
213 |
|
|
235 |
ocean may be influenced by rotation when the deformation radius is smaller |
ocean may be influenced by rotation when the deformation radius is smaller |
236 |
than the width of the cooling region. Rather than gravity plumes, the |
than the width of the cooling region. Rather than gravity plumes, the |
237 |
mechanism for moving dense fluid down the shelf is then through geostrophic |
mechanism for moving dense fluid down the shelf is then through geostrophic |
238 |
eddies. The simulation shown in the figure \ref{fig::convect-and-topo} |
eddies. The simulation shown in the figure \ref{fig:convect-and-topo} |
239 |
(blue is cold dense fluid, red is |
(blue is cold dense fluid, red is |
240 |
warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to |
warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to |
241 |
trigger convection by surface cooling. The cold, dense water falls down the |
trigger convection by surface cooling. The cold, dense water falls down the |
275 |
|
|
276 |
As one example of application of the MITgcm adjoint, Figure \ref{fig:hf-sensitivity} |
As one example of application of the MITgcm adjoint, Figure \ref{fig:hf-sensitivity} |
277 |
maps the gradient $\frac{\partial J}{\partial \mathcal{H}}$where $J$ is the magnitude |
maps the gradient $\frac{\partial J}{\partial \mathcal{H}}$where $J$ is the magnitude |
278 |
of the overturning streamfunction shown in figure \ref{fig:large-scale-circ} |
of the overturning stream-function shown in figure \ref{fig:large-scale-circ} |
279 |
at 60$^{\circ }$N and $ |
at 60$^{\circ }$N and $ |
280 |
\mathcal{H}(\lambda,\varphi)$ is the mean, local air-sea heat flux over |
\mathcal{H}(\lambda,\varphi)$ is the mean, local air-sea heat flux over |
281 |
a 100 year period. We see that $J$ is |
a 100 year period. We see that $J$ is |
292 |
An important application of MITgcm is in state estimation of the global |
An important application of MITgcm is in state estimation of the global |
293 |
ocean circulation. An appropriately defined `cost function', which measures |
ocean circulation. An appropriately defined `cost function', which measures |
294 |
the departure of the model from observations (both remotely sensed and |
the departure of the model from observations (both remotely sensed and |
295 |
insitu) over an interval of time, is minimized by adjusting `control |
in-situ) over an interval of time, is minimized by adjusting `control |
296 |
parameters' such as air-sea fluxes, the wind field, the initial conditions |
parameters' such as air-sea fluxes, the wind field, the initial conditions |
297 |
etc. Figure \ref{fig:assimilated-globes} shows an estimate of the time-mean |
etc. Figure \ref{fig:assimilated-globes} shows an estimate of the time-mean |
298 |
surface elevation of the ocean obtained by bringing the model in to |
surface elevation of the ocean obtained by bringing the model in to |
321 |
\subsection{Simulations of laboratory experiments} |
\subsection{Simulations of laboratory experiments} |
322 |
|
|
323 |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
324 |
laboratory experiment enquiring in to the dynamics of the Antarctic Circumpolar Current (ACC). An |
laboratory experiment inquiring in to the dynamics of the Antarctic Circumpolar Current (ACC). An |
325 |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
326 |
free surface by a rotating heated disk. The combined action of mechanical |
free surface by a rotating heated disk. The combined action of mechanical |
327 |
and thermal forcing creates a lens of fluid which becomes baroclinically |
and thermal forcing creates a lens of fluid which becomes baroclinically |
370 |
\begin{equation*} |
\begin{equation*} |
371 |
\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}} |
372 |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
373 |
\text{ horizontal mtm} |
\text{ horizontal mtm} \label{eq:horizontal_mtm} |
374 |
\end{equation*} |
\end{equation*} |
375 |
|
|
376 |
\begin{equation*} |
\begin{equation} |
377 |
\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{ |
378 |
v}}\right) +\frac{\partial \phi }{\partial r}+b=\mathcal{F}_{\dot{r}}\text{ |
v}}\right) +\frac{\partial \phi }{\partial r}+b=\mathcal{F}_{\dot{r}}\text{ |
379 |
vertical mtm} |
vertical mtm} \label{eq:vertical_mtm} |
380 |
\end{equation*} |
\end{equation} |
381 |
|
|
382 |
\begin{equation} |
\begin{equation} |
383 |
\mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{ |
\mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{ |
384 |
\partial r}=0\text{ continuity} \label{eq:continuous} |
\partial r}=0\text{ continuity} \label{eq:continuity} |
385 |
\end{equation} |
\end{equation} |
386 |
|
|
387 |
\begin{equation*} |
\begin{equation} |
388 |
b=b(\theta ,S,r)\text{ equation of state} |
b=b(\theta ,S,r)\text{ equation of state} \label{eq:equation_of_state} |
389 |
\end{equation*} |
\end{equation} |
390 |
|
|
391 |
\begin{equation*} |
\begin{equation} |
392 |
\frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature} |
\frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature} |
393 |
\end{equation*} |
\label{eq:potential_temperature} |
394 |
|
\end{equation} |
395 |
|
|
396 |
\begin{equation*} |
\begin{equation} |
397 |
\frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity} |
\frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity} |
398 |
\end{equation*} |
\label{eq:humidity_salt} |
399 |
|
\end{equation} |
400 |
|
|
401 |
Here: |
Here: |
402 |
|
|
476 |
|
|
477 |
\begin{equation} |
\begin{equation} |
478 |
\dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \ |
\dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \ |
479 |
(oceansurface,bottomoftheatmosphere)} \label{eq:movingbc} |
(ocean surface,bottom of the atmosphere)} \label{eq:movingbc} |
480 |
\end{equation} |
\end{equation} |
481 |
|
|
482 |
Here |
Here |
569 |
atmosphere)} \label{eq:moving-bc-atmos} |
atmosphere)} \label{eq:moving-bc-atmos} |
570 |
\end{eqnarray} |
\end{eqnarray} |
571 |
|
|
572 |
Then the (hydrostatic form of) eq(\ref{eq:continuous}) yields a consistent |
Then the (hydrostatic form of) equations (\ref{eq:horizontal_mtm}-\ref{eq:humidity_salt}) |
573 |
set of atmospheric equations which, for convenience, are written out in $p$ |
yields a consistent set of atmospheric equations which, for convenience, are written out in $p$ |
574 |
coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}). |
coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}). |
575 |
|
|
576 |
\subsection{Ocean} |
\subsection{Ocean} |
606 |
\end{eqnarray} |
\end{eqnarray} |
607 |
where $\eta $ is the elevation of the free surface. |
where $\eta $ is the elevation of the free surface. |
608 |
|
|
609 |
Then eq(\ref{eq:continuous}) yields a consistent set of oceanic equations |
Then equations (\ref{eq:horizontal_mtm}-\ref{eq:humidity_salt}) yield a consistent set |
610 |
|
of oceanic equations |
611 |
which, for convenience, are written out in $z$ coordinates in Appendix Ocean |
which, for convenience, are written out in $z$ coordinates in Appendix Ocean |
612 |
- see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}). |
- see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}). |
613 |
|
|
620 |
\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) |
621 |
\label{eq:phi-split} |
\label{eq:phi-split} |
622 |
\end{equation} |
\end{equation} |
623 |
and write eq(\ref{incompressible}a,b) in the form: |
and write eq(\ref{eq:incompressible}) in the form: |
624 |
|
|
625 |
\begin{equation} |
\begin{equation} |
626 |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
713 |
|
|
714 |
Grad and div operators in spherical coordinates are defined in appendix |
Grad and div operators in spherical coordinates are defined in appendix |
715 |
OPERATORS. |
OPERATORS. |
|
\marginpar{ |
|
|
Fig.6 Spherical polar coordinate system.} |
|
716 |
|
|
717 |
%%CNHbegin |
%%CNHbegin |
718 |
\input{part1/sphere_coord_figure.tex} |
\input{part1/sphere_coord_figure.tex} |
775 |
three dimensional elliptic equation must be solved subject to Neumann |
three dimensional elliptic equation must be solved subject to Neumann |
776 |
boundary conditions (see below). It is important to note that use of the |
boundary conditions (see below). It is important to note that use of the |
777 |
full \textbf{NH} does not admit any new `fast' waves in to the system - the |
full \textbf{NH} does not admit any new `fast' waves in to the system - the |
778 |
incompressible condition eq(\ref{eq:continuous})c has already filtered out |
incompressible condition eq(\ref{eq:continuity}) has already filtered out |
779 |
acoustic modes. It does, however, ensure that the gravity waves are treated |
acoustic modes. It does, however, ensure that the gravity waves are treated |
780 |
accurately with an exact dispersion relation. The \textbf{NH} set has a |
accurately with an exact dispersion relation. The \textbf{NH} set has a |
781 |
complete angular momentum principle and consistent energetics - see White |
complete angular momentum principle and consistent energetics - see White |
824 |
\subsection{Solution strategy} |
\subsection{Solution strategy} |
825 |
|
|
826 |
The method of solution employed in the \textbf{HPE}, \textbf{QH} and \textbf{ |
The method of solution employed in the \textbf{HPE}, \textbf{QH} and \textbf{ |
827 |
NH} models is summarized in Fig.7. |
NH} models is summarized in Figure \ref{fig:solution-strategy}. |
828 |
\marginpar{ |
Under all dynamics, a 2-d elliptic equation is |
|
Fig.7 Solution strategy} Under all dynamics, a 2-d elliptic equation is |
|
829 |
first solved to find the surface pressure and the hydrostatic pressure at |
first solved to find the surface pressure and the hydrostatic pressure at |
830 |
any level computed from the weight of fluid above. Under \textbf{HPE} and |
any level computed from the weight of fluid above. Under \textbf{HPE} and |
831 |
\textbf{QH} dynamics, the horizontal momentum equations are then stepped |
\textbf{QH} dynamics, the horizontal momentum equations are then stepped |
882 |
|
|
883 |
\subsubsection{Surface pressure} |
\subsubsection{Surface pressure} |
884 |
|
|
885 |
The surface pressure equation can be obtained by integrating continuity, ( |
The surface pressure equation can be obtained by integrating continuity, |
886 |
\ref{eq:continuous})c, vertically from $r=R_{fixed}$ to $r=R_{moving}$ |
(\ref{eq:continuity}), vertically from $r=R_{fixed}$ to $r=R_{moving}$ |
887 |
|
|
888 |
\begin{equation*} |
\begin{equation*} |
889 |
\int_{R_{fixed}}^{R_{moving}}\left( \mathbf{\nabla }_{h}\cdot \vec{\mathbf{v} |
\int_{R_{fixed}}^{R_{moving}}\left( \mathbf{\nabla }_{h}\cdot \vec{\mathbf{v} |
908 |
where we have incorporated a source term. |
where we have incorporated a source term. |
909 |
|
|
910 |
Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential |
Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential |
911 |
(atmospheric model), in (\ref{mtm-split}), the horizontal gradient term can |
(atmospheric model), in (\ref{eq:mom-h}), the horizontal gradient term can |
912 |
be written |
be written |
913 |
\begin{equation} |
\begin{equation} |
914 |
\mathbf{\nabla }_{h}\phi _{s}=\mathbf{\nabla }_{h}\left( b_{s}\eta \right) |
\mathbf{\nabla }_{h}\phi _{s}=\mathbf{\nabla }_{h}\left( b_{s}\eta \right) |
916 |
\end{equation} |
\end{equation} |
917 |
where $b_{s}$ is the buoyancy at the surface. |
where $b_{s}$ is the buoyancy at the surface. |
918 |
|
|
919 |
In the hydrostatic limit ($\epsilon _{nh}=0$), Eqs(\ref{eq:mom-h}), (\ref |
In the hydrostatic limit ($\epsilon _{nh}=0$), equations (\ref{eq:mom-h}), (\ref |
920 |
{eq:free-surface}) and (\ref{eq:phi-surf}) can be solved by inverting a 2-d |
{eq:free-surface}) and (\ref{eq:phi-surf}) can be solved by inverting a 2-d |
921 |
elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free |
elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free |
922 |
surface' and `rigid lid' approaches are available. |
surface' and `rigid lid' approaches are available. |
923 |
|
|
924 |
\subsubsection{Non-hydrostatic pressure} |
\subsubsection{Non-hydrostatic pressure} |
925 |
|
|
926 |
Taking the horizontal divergence of (\ref{hor-mtm}) and adding $\frac{ |
Taking the horizontal divergence of (\ref{eq:mom-h}) and adding |
927 |
\partial }{\partial r}$ of (\ref{vertmtm}), invoking the continuity equation |
$\frac{\partial }{\partial r}$ of (\ref{eq:mom-w}), invoking the continuity equation |
928 |
(\ref{incompressible}), we deduce that: |
(\ref{eq:continuity}), we deduce that: |
929 |
|
|
930 |
\begin{equation} |
\begin{equation} |
931 |
\nabla _{3}^{2}\phi _{nh}=\nabla .\vec{\mathbf{G}}_{\vec{v}}-\left( \mathbf{ |
\nabla _{3}^{2}\phi _{nh}=\nabla .\vec{\mathbf{G}}_{\vec{v}}-\left( \mathbf{ |
955 |
depending on the form chosen for the dissipative terms in the momentum |
depending on the form chosen for the dissipative terms in the momentum |
956 |
equations - see below. |
equations - see below. |
957 |
|
|
958 |
Eq.(\ref{nonormalflow}) implies, making use of (\ref{mtm-split}), that: |
Eq.(\ref{nonormalflow}) implies, making use of (\ref{eq:mom-h}), that: |
959 |
|
|
960 |
\begin{equation} |
\begin{equation} |
961 |
\widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}} |
\widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}} |
995 |
converges rapidly because $\phi _{nh}\ $is then only a small correction to |
converges rapidly because $\phi _{nh}\ $is then only a small correction to |
996 |
the hydrostatic pressure field (see the discussion in Marshall et al, a,b). |
the hydrostatic pressure field (see the discussion in Marshall et al, a,b). |
997 |
|
|
998 |
The solution $\phi _{nh}\ $to (\ref{eq:3d-invert}) and (\ref{homneuman}) |
The solution $\phi _{nh}\ $to (\ref{eq:3d-invert}) and (\ref{eq:inhom-neumann-nh}) |
999 |
does not vanish at $r=R_{moving}$, and so refines the pressure there. |
does not vanish at $r=R_{moving}$, and so refines the pressure there. |
1000 |
|
|
1001 |
\subsection{Forcing/dissipation} |
\subsection{Forcing/dissipation} |
1003 |
\subsubsection{Forcing} |
\subsubsection{Forcing} |
1004 |
|
|
1005 |
The forcing terms $\mathcal{F}$ on the rhs of the equations are provided by |
The forcing terms $\mathcal{F}$ on the rhs of the equations are provided by |
1006 |
`physics packages' described in detail in chapter ??. |
`physics packages' and forcing packages. These are described later on. |
1007 |
|
|
1008 |
\subsubsection{Dissipation} |
\subsubsection{Dissipation} |
1009 |
|
|
1051 |
\subsection{Vector invariant form} |
\subsection{Vector invariant form} |
1052 |
|
|
1053 |
For some purposes it is advantageous to write momentum advection in eq(\ref |
For some purposes it is advantageous to write momentum advection in eq(\ref |
1054 |
{hor-mtm}) and (\ref{vertmtm}) in the (so-called) `vector invariant' form: |
{eq:horizontal_mtm}) and (\ref{eq:vertical_mtm}) in the (so-called) `vector invariant' form: |
1055 |
|
|
1056 |
\begin{equation} |
\begin{equation} |
1057 |
\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} |
1069 |
|
|
1070 |
\subsection{Adjoint} |
\subsection{Adjoint} |
1071 |
|
|
1072 |
Tangent linear and adjoint counterparts of the forward model and described |
Tangent linear and adjoint counterparts of the forward model are described |
1073 |
in Chapter 5. |
in Chapter 5. |
1074 |
|
|
1075 |
% $Header$ |
% $Header$ |
1191 |
The final form of the HPE's in p coordinates is then: |
The final form of the HPE's in p coordinates is then: |
1192 |
\begin{eqnarray} |
\begin{eqnarray} |
1193 |
\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}} |
1194 |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \\ |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\ |
1195 |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
1196 |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
1197 |
\partial p} &=&0 \\ |
\partial p} &=&0 \\ |
1198 |
\frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\ |
\frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\ |
1199 |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } \label{eq:atmos-prime} |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } |
1200 |
\end{eqnarray} |
\end{eqnarray} |
1201 |
|
|
1202 |
% $Header$ |
% $Header$ |
1215 |
\epsilon _{nh}\frac{Dw}{Dt}+g+\frac{1}{\rho }\frac{\partial p}{\partial z} |
\epsilon _{nh}\frac{Dw}{Dt}+g+\frac{1}{\rho }\frac{\partial p}{\partial z} |
1216 |
&=&\epsilon _{nh}\mathcal{F}_{w} \\ |
&=&\epsilon _{nh}\mathcal{F}_{w} \\ |
1217 |
\frac{1}{\rho }\frac{D\rho }{Dt}+\mathbf{\nabla }_{z}\cdot \vec{\mathbf{v}} |
\frac{1}{\rho }\frac{D\rho }{Dt}+\mathbf{\nabla }_{z}\cdot \vec{\mathbf{v}} |
1218 |
_{h}+\frac{\partial w}{\partial z} &=&0 \\ |
_{h}+\frac{\partial w}{\partial z} &=&0 \label{eq-zns-cont}\\ |
1219 |
\rho &=&\rho (\theta ,S,p) \\ |
\rho &=&\rho (\theta ,S,p) \label{eq-zns-eos}\\ |
1220 |
\frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \\ |
\frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \label{eq-zns-heat}\\ |
1221 |
\frac{DS}{Dt} &=&\mathcal{Q}_{s} \label{eq:non-boussinesq} |
\frac{DS}{Dt} &=&\mathcal{Q}_{s} \label{eq-zns-salt} |
1222 |
|
\label{eq:non-boussinesq} |
1223 |
\end{eqnarray} |
\end{eqnarray} |
1224 |
These equations permit acoustics modes, inertia-gravity waves, |
These equations permit acoustics modes, inertia-gravity waves, |
1225 |
non-hydrostatic motions, a geostrophic (Rossby) mode and a thermo-haline |
non-hydrostatic motions, a geostrophic (Rossby) mode and a thermohaline |
1226 |
mode. As written, they cannot be integrated forward consistently - if we |
mode. As written, they cannot be integrated forward consistently - if we |
1227 |
step $\rho $ forward in (\ref{eq-zns-cont}), the answer will not be |
step $\rho $ forward in (\ref{eq-zns-cont}), the answer will not be |
1228 |
consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref |
consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref |
1238 |
\end{equation} |
\end{equation} |
1239 |
|
|
1240 |
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 the |
1241 |
reciprocal of the sound speed ($c_{s}$) squared. Substituting into \ref |
reciprocal of the sound speed ($c_{s}$) squared. Substituting into \ref{eq-zns-cont} gives: |
|
{eq-zns-cont} gives: |
|
1242 |
\begin{equation} |
\begin{equation} |
1243 |
\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{ |
1244 |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |