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 Eighth ECMWF Workshop on the Use of Parallel Processors |
123 |
|
in Meteorology, pages 406-425 |
124 |
|
World Scientific Publishing Co: UK |
125 |
|
|
126 |
|
Marotzke, J, Giering,R., Zhang, K.Q., Stammer,D., Hill,C., and T.Lee, (1999) |
127 |
|
Construction of the adjoint MIT ocean general circulation model and |
128 |
|
application to Atlantic heat transport variability |
129 |
|
J. Geophysical Res., 104(C12), 29,529-29,547. |
130 |
|
|
131 |
|
|
132 |
|
\end{verbatim} |
133 |
|
|
134 |
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 |
135 |
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. |
147 |
numerical algorithm and implementation that lie behind these calculations is |
numerical algorithm and implementation that lie behind these calculations is |
148 |
given later. Indeed many of the illustrative examples shown below can be |
given later. Indeed many of the illustrative examples shown below can be |
149 |
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 |
150 |
running linux, together with a FORTRAN\ 77 compiler) and follow the examples |
running Linux, together with a FORTRAN\ 77 compiler) and follow the examples |
151 |
described in detail in the documentation. |
described in detail in the documentation. |
152 |
|
|
153 |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
\subsection{Global atmosphere: `Held-Suarez' benchmark} |
171 |
%% CNHend |
%% CNHend |
172 |
|
|
173 |
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 |
174 |
globe permitting a uniform gridding and obviated the need to Fourier filter. |
globe permitting a uniform griding and obviated the need to Fourier filter. |
175 |
The `vector-invariant' form of MITgcm supports any orthogonal curvilinear |
The `vector-invariant' form of MITgcm supports any orthogonal curvilinear |
176 |
grid, of which the cubed sphere is just one of many choices. |
grid, of which the cubed sphere is just one of many choices. |
177 |
|
|
208 |
visible. |
visible. |
209 |
|
|
210 |
%% CNHbegin |
%% CNHbegin |
211 |
\input{part1/ocean_gyres_figure} |
\input{part1/atl6_figure} |
212 |
%% CNHend |
%% CNHend |
213 |
|
|
214 |
|
|
236 |
ocean may be influenced by rotation when the deformation radius is smaller |
ocean may be influenced by rotation when the deformation radius is smaller |
237 |
than the width of the cooling region. Rather than gravity plumes, the |
than the width of the cooling region. Rather than gravity plumes, the |
238 |
mechanism for moving dense fluid down the shelf is then through geostrophic |
mechanism for moving dense fluid down the shelf is then through geostrophic |
239 |
eddies. The simulation shown in the figure \ref{fig::convect-and-topo} |
eddies. The simulation shown in the figure \ref{fig:convect-and-topo} |
240 |
(blue is cold dense fluid, red is |
(blue is cold dense fluid, red is |
241 |
warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to |
warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to |
242 |
trigger convection by surface cooling. The cold, dense water falls down the |
trigger convection by surface cooling. The cold, dense water falls down the |
276 |
|
|
277 |
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} |
278 |
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 |
279 |
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} |
280 |
at 60$^{\circ }$N and $ |
at 60$^{\circ }$N and $ |
281 |
\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 |
282 |
a 100 year period. We see that $J$ is |
a 100 year period. We see that $J$ is |
293 |
An important application of MITgcm is in state estimation of the global |
An important application of MITgcm is in state estimation of the global |
294 |
ocean circulation. An appropriately defined `cost function', which measures |
ocean circulation. An appropriately defined `cost function', which measures |
295 |
the departure of the model from observations (both remotely sensed and |
the departure of the model from observations (both remotely sensed and |
296 |
insitu) over an interval of time, is minimized by adjusting `control |
in-situ) over an interval of time, is minimized by adjusting `control |
297 |
parameters' such as air-sea fluxes, the wind field, the initial conditions |
parameters' such as air-sea fluxes, the wind field, the initial conditions |
298 |
etc. Figure \ref{fig:assimilated-globes} shows an estimate of the time-mean |
etc. Figure \ref{fig:assimilated-globes} shows the large scale planetary |
299 |
surface elevation of the ocean obtained by bringing the model in to |
circulation and a Hopf-Muller plot of Equatorial sea-surface height. |
300 |
|
Both are obtained from assimilation bringing the model in to |
301 |
consistency with altimetric and in-situ observations over the period |
consistency with altimetric and in-situ observations over the period |
302 |
1992-1997. {\bf CHANGE THIS TEXT - FIG FROM PATRICK/CARL/DETLEF} |
1992-1997. |
303 |
|
|
304 |
%% CNHbegin |
%% CNHbegin |
305 |
\input{part1/globes_figure} |
\input{part1/assim_figure} |
306 |
%% CNHend |
%% CNHend |
307 |
|
|
308 |
\subsection{Ocean biogeochemical cycles} |
\subsection{Ocean biogeochemical cycles} |
323 |
\subsection{Simulations of laboratory experiments} |
\subsection{Simulations of laboratory experiments} |
324 |
|
|
325 |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a |
326 |
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 |
327 |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
initially homogeneous tank of water ($1m$ in diameter) is driven from its |
328 |
free surface by a rotating heated disk. The combined action of mechanical |
free surface by a rotating heated disk. The combined action of mechanical |
329 |
and thermal forcing creates a lens of fluid which becomes baroclinically |
and thermal forcing creates a lens of fluid which becomes baroclinically |
372 |
\begin{equation*} |
\begin{equation*} |
373 |
\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}} |
374 |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
\right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}} |
375 |
\text{ horizontal mtm} |
\text{ horizontal mtm} \label{eq:horizontal_mtm} |
376 |
\end{equation*} |
\end{equation*} |
377 |
|
|
378 |
\begin{equation*} |
\begin{equation} |
379 |
\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{ |
380 |
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{ |
381 |
vertical mtm} |
vertical mtm} \label{eq:vertical_mtm} |
382 |
\end{equation*} |
\end{equation} |
383 |
|
|
384 |
\begin{equation} |
\begin{equation} |
385 |
\mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{ |
\mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{ |
386 |
\partial r}=0\text{ continuity} \label{eq:continuous} |
\partial r}=0\text{ continuity} \label{eq:continuity} |
387 |
\end{equation} |
\end{equation} |
388 |
|
|
389 |
\begin{equation*} |
\begin{equation} |
390 |
b=b(\theta ,S,r)\text{ equation of state} |
b=b(\theta ,S,r)\text{ equation of state} \label{eq:equation_of_state} |
391 |
\end{equation*} |
\end{equation} |
392 |
|
|
393 |
\begin{equation*} |
\begin{equation} |
394 |
\frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature} |
\frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature} |
395 |
\end{equation*} |
\label{eq:potential_temperature} |
396 |
|
\end{equation} |
397 |
|
|
398 |
\begin{equation*} |
\begin{equation} |
399 |
\frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity} |
\frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity} |
400 |
\end{equation*} |
\label{eq:humidity_salt} |
401 |
|
\end{equation} |
402 |
|
|
403 |
Here: |
Here: |
404 |
|
|
478 |
|
|
479 |
\begin{equation} |
\begin{equation} |
480 |
\dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \ |
\dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \ |
481 |
(oceansurface,bottomoftheatmosphere)} \label{eq:movingbc} |
(ocean surface,bottom of the atmosphere)} \label{eq:movingbc} |
482 |
\end{equation} |
\end{equation} |
483 |
|
|
484 |
Here |
Here |
571 |
atmosphere)} \label{eq:moving-bc-atmos} |
atmosphere)} \label{eq:moving-bc-atmos} |
572 |
\end{eqnarray} |
\end{eqnarray} |
573 |
|
|
574 |
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}) |
575 |
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 $p$ |
576 |
coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}). |
coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}). |
577 |
|
|
578 |
\subsection{Ocean} |
\subsection{Ocean} |
608 |
\end{eqnarray} |
\end{eqnarray} |
609 |
where $\eta $ is the elevation of the free surface. |
where $\eta $ is the elevation of the free surface. |
610 |
|
|
611 |
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 |
612 |
|
of oceanic equations |
613 |
which, for convenience, are written out in $z$ coordinates in Appendix Ocean |
which, for convenience, are written out in $z$ coordinates in Appendix Ocean |
614 |
- see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}). |
- see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}). |
615 |
|
|
622 |
\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) |
623 |
\label{eq:phi-split} |
\label{eq:phi-split} |
624 |
\end{equation} |
\end{equation} |
625 |
and write eq(\ref{incompressible}a,b) in the form: |
and write eq(\ref{eq:incompressible}) in the form: |
626 |
|
|
627 |
\begin{equation} |
\begin{equation} |
628 |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
\frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi |
715 |
|
|
716 |
Grad and div operators in spherical coordinates are defined in appendix |
Grad and div operators in spherical coordinates are defined in appendix |
717 |
OPERATORS. |
OPERATORS. |
|
\marginpar{ |
|
|
Fig.6 Spherical polar coordinate system.} |
|
718 |
|
|
719 |
%%CNHbegin |
%%CNHbegin |
720 |
\input{part1/sphere_coord_figure.tex} |
\input{part1/sphere_coord_figure.tex} |
777 |
three dimensional elliptic equation must be solved subject to Neumann |
three dimensional elliptic equation must be solved subject to Neumann |
778 |
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 |
779 |
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 |
780 |
incompressible condition eq(\ref{eq:continuous})c has already filtered out |
incompressible condition eq(\ref{eq:continuity}) has already filtered out |
781 |
acoustic modes. It does, however, ensure that the gravity waves are treated |
acoustic modes. It does, however, ensure that the gravity waves are treated |
782 |
accurately with an exact dispersion relation. The \textbf{NH} set has a |
accurately with an exact dispersion relation. The \textbf{NH} set has a |
783 |
complete angular momentum principle and consistent energetics - see White |
complete angular momentum principle and consistent energetics - see White |
826 |
\subsection{Solution strategy} |
\subsection{Solution strategy} |
827 |
|
|
828 |
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{ |
829 |
NH} models is summarized in Fig.7. |
NH} models is summarized in Figure \ref{fig:solution-strategy}. |
830 |
\marginpar{ |
Under all dynamics, a 2-d elliptic equation is |
|
Fig.7 Solution strategy} Under all dynamics, a 2-d elliptic equation is |
|
831 |
first solved to find the surface pressure and the hydrostatic pressure at |
first solved to find the surface pressure and the hydrostatic pressure at |
832 |
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 |
833 |
\textbf{QH} dynamics, the horizontal momentum equations are then stepped |
\textbf{QH} dynamics, the horizontal momentum equations are then stepped |
884 |
|
|
885 |
\subsubsection{Surface pressure} |
\subsubsection{Surface pressure} |
886 |
|
|
887 |
The surface pressure equation can be obtained by integrating continuity, ( |
The surface pressure equation can be obtained by integrating continuity, |
888 |
\ref{eq:continuous})c, vertically from $r=R_{fixed}$ to $r=R_{moving}$ |
(\ref{eq:continuity}), vertically from $r=R_{fixed}$ to $r=R_{moving}$ |
889 |
|
|
890 |
\begin{equation*} |
\begin{equation*} |
891 |
\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} |
910 |
where we have incorporated a source term. |
where we have incorporated a source term. |
911 |
|
|
912 |
Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential |
Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential |
913 |
(atmospheric model), in (\ref{mtm-split}), the horizontal gradient term can |
(atmospheric model), in (\ref{eq:mom-h}), the horizontal gradient term can |
914 |
be written |
be written |
915 |
\begin{equation} |
\begin{equation} |
916 |
\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) |
918 |
\end{equation} |
\end{equation} |
919 |
where $b_{s}$ is the buoyancy at the surface. |
where $b_{s}$ is the buoyancy at the surface. |
920 |
|
|
921 |
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 |
922 |
{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 |
923 |
elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free |
elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free |
924 |
surface' and `rigid lid' approaches are available. |
surface' and `rigid lid' approaches are available. |
925 |
|
|
926 |
\subsubsection{Non-hydrostatic pressure} |
\subsubsection{Non-hydrostatic pressure} |
927 |
|
|
928 |
Taking the horizontal divergence of (\ref{hor-mtm}) and adding $\frac{ |
Taking the horizontal divergence of (\ref{eq:mom-h}) and adding |
929 |
\partial }{\partial r}$ of (\ref{vertmtm}), invoking the continuity equation |
$\frac{\partial }{\partial r}$ of (\ref{eq:mom-w}), invoking the continuity equation |
930 |
(\ref{incompressible}), we deduce that: |
(\ref{eq:continuity}), we deduce that: |
931 |
|
|
932 |
\begin{equation} |
\begin{equation} |
933 |
\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{ |
957 |
depending on the form chosen for the dissipative terms in the momentum |
depending on the form chosen for the dissipative terms in the momentum |
958 |
equations - see below. |
equations - see below. |
959 |
|
|
960 |
Eq.(\ref{nonormalflow}) implies, making use of (\ref{mtm-split}), that: |
Eq.(\ref{nonormalflow}) implies, making use of (\ref{eq:mom-h}), that: |
961 |
|
|
962 |
\begin{equation} |
\begin{equation} |
963 |
\widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}} |
\widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}} |
997 |
converges rapidly because $\phi _{nh}\ $is then only a small correction to |
converges rapidly because $\phi _{nh}\ $is then only a small correction to |
998 |
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). |
999 |
|
|
1000 |
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}) |
1001 |
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. |
1002 |
|
|
1003 |
\subsection{Forcing/dissipation} |
\subsection{Forcing/dissipation} |
1005 |
\subsubsection{Forcing} |
\subsubsection{Forcing} |
1006 |
|
|
1007 |
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 |
1008 |
`physics packages' described in detail in chapter ??. |
`physics packages' and forcing packages. These are described later on. |
1009 |
|
|
1010 |
\subsubsection{Dissipation} |
\subsubsection{Dissipation} |
1011 |
|
|
1053 |
\subsection{Vector invariant form} |
\subsection{Vector invariant form} |
1054 |
|
|
1055 |
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 |
1056 |
{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: |
1057 |
|
|
1058 |
\begin{equation} |
\begin{equation} |
1059 |
\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} |
1071 |
|
|
1072 |
\subsection{Adjoint} |
\subsection{Adjoint} |
1073 |
|
|
1074 |
Tangent linear and adjoint counterparts of the forward model and described |
Tangent linear and adjoint counterparts of the forward model are described |
1075 |
in Chapter 5. |
in Chapter 5. |
1076 |
|
|
1077 |
% $Header$ |
% $Header$ |
1193 |
The final form of the HPE's in p coordinates is then: |
The final form of the HPE's in p coordinates is then: |
1194 |
\begin{eqnarray} |
\begin{eqnarray} |
1195 |
\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}} |
1196 |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \\ |
_{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\ |
1197 |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
\frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\ |
1198 |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
\mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{ |
1199 |
\partial p} &=&0 \\ |
\partial p} &=&0 \\ |
1200 |
\frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\ |
\frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\ |
1201 |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } \label{eq:atmos-prime} |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } |
1202 |
\end{eqnarray} |
\end{eqnarray} |
1203 |
|
|
1204 |
% $Header$ |
% $Header$ |
1217 |
\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} |
1218 |
&=&\epsilon _{nh}\mathcal{F}_{w} \\ |
&=&\epsilon _{nh}\mathcal{F}_{w} \\ |
1219 |
\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}} |
1220 |
_{h}+\frac{\partial w}{\partial z} &=&0 \\ |
_{h}+\frac{\partial w}{\partial z} &=&0 \label{eq-zns-cont}\\ |
1221 |
\rho &=&\rho (\theta ,S,p) \\ |
\rho &=&\rho (\theta ,S,p) \label{eq-zns-eos}\\ |
1222 |
\frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \\ |
\frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \label{eq-zns-heat}\\ |
1223 |
\frac{DS}{Dt} &=&\mathcal{Q}_{s} \label{eq:non-boussinesq} |
\frac{DS}{Dt} &=&\mathcal{Q}_{s} \label{eq-zns-salt} |
1224 |
|
\label{eq:non-boussinesq} |
1225 |
\end{eqnarray} |
\end{eqnarray} |
1226 |
These equations permit acoustics modes, inertia-gravity waves, |
These equations permit acoustics modes, inertia-gravity waves, |
1227 |
non-hydrostatic motions, a geostrophic (Rossby) mode and a thermo-haline |
non-hydrostatic motions, a geostrophic (Rossby) mode and a thermohaline |
1228 |
mode. As written, they cannot be integrated forward consistently - if we |
mode. As written, they cannot be integrated forward consistently - if we |
1229 |
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 |
1230 |
consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref |
consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref |
1240 |
\end{equation} |
\end{equation} |
1241 |
|
|
1242 |
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 |
1243 |
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: |
|
1244 |
\begin{equation} |
\begin{equation} |
1245 |
\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{ |
1246 |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |
v}}+\partial _{z}w\approx 0 \label{eq-zns-pressure} |