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35 |
% Section: Overview |
% Section: Overview |
36 |
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% $Header$ |
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% $Name$ |
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37 |
This document provides the reader with the information necessary to |
This document provides the reader with the information necessary to |
38 |
carry out numerical experiments using MITgcm. It gives a comprehensive |
carry out numerical experiments using MITgcm. It gives a comprehensive |
39 |
description of the continuous equations on which the model is based, the |
description of the continuous equations on which the model is based, the |
58 |
models - see fig \ref{fig:onemodel} |
models - see fig \ref{fig:onemodel} |
59 |
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|
60 |
%% CNHbegin |
%% CNHbegin |
61 |
\input{part1/one_model_figure} |
\input{s_overview/text/one_model_figure} |
62 |
%% CNHend |
%% CNHend |
63 |
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|
64 |
\item it has a non-hydrostatic capability and so can be used to study both |
\item it has a non-hydrostatic capability and so can be used to study both |
65 |
small-scale and large scale processes - see fig \ref{fig:all-scales} |
small-scale and large scale processes - see fig \ref{fig:all-scales} |
66 |
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|
67 |
%% CNHbegin |
%% CNHbegin |
68 |
\input{part1/all_scales_figure} |
\input{s_overview/text/all_scales_figure} |
69 |
%% CNHend |
%% CNHend |
70 |
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|
71 |
\item finite volume techniques are employed yielding an intuitive |
\item finite volume techniques are employed yielding an intuitive |
73 |
orthogonal curvilinear grids and shaved cells - see fig \ref{fig:finite-volumes} |
orthogonal curvilinear grids and shaved cells - see fig \ref{fig:finite-volumes} |
74 |
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|
75 |
%% CNHbegin |
%% CNHbegin |
76 |
\input{part1/fvol_figure} |
\input{s_overview/text/fvol_figure} |
77 |
%% CNHend |
%% CNHend |
78 |
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|
79 |
\item tangent linear and adjoint counterparts are automatically maintained |
\item tangent linear and adjoint counterparts are automatically maintained |
84 |
computational platforms. |
computational platforms. |
85 |
\end{itemize} |
\end{itemize} |
86 |
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|
87 |
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|
88 |
Key publications reporting on and charting the development of the model are |
Key publications reporting on and charting the development of the model are |
89 |
\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,mars-eta:98,adcroft:99,hill:99,maro-eta:99,adcroft:04a,adcroft:04b,marshall:04} |
90 |
|
(an overview on the model formulation can also be found in \cite{adcroft:04c}): |
91 |
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|
92 |
\begin{verbatim} |
\begin{verbatim} |
93 |
Hill, C. and J. Marshall, (1995) |
Hill, C. and J. Marshall, (1995) |
136 |
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 |
137 |
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. |
138 |
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% $Header$ |
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% $Name$ |
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139 |
\section{Illustrations of the model in action} |
\section{Illustrations of the model in action} |
140 |
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|
141 |
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, |
142 |
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 |
143 |
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 |
144 |
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 |
161 |
|
|
162 |
Figure \ref{fig:eddy_cs} shows an instantaneous plot of the 500$mb$ |
Figure \ref{fig:eddy_cs} shows an instantaneous plot of the 500$mb$ |
163 |
temperature field obtained using the atmospheric isomorph of MITgcm run at |
temperature field obtained using the atmospheric isomorph of MITgcm run at |
164 |
2.8$^{\circ }$ resolution on the cubed sphere. We see cold air over the pole |
$2.8^{\circ }$ resolution on the cubed sphere. We see cold air over the pole |
165 |
(blue) and warm air along an equatorial band (red). Fully developed |
(blue) and warm air along an equatorial band (red). Fully developed |
166 |
baroclinic eddies spawned in the northern hemisphere storm track are |
baroclinic eddies spawned in the northern hemisphere storm track are |
167 |
evident. There are no mountains or land-sea contrast in this calculation, |
evident. There are no mountains or land-sea contrast in this calculation, |
171 |
there are no mountains or land-sea contrast. |
there are no mountains or land-sea contrast. |
172 |
|
|
173 |
%% CNHbegin |
%% CNHbegin |
174 |
\input{part1/cubic_eddies_figure} |
\input{s_overview/text/cubic_eddies_figure} |
175 |
%% CNHend |
%% CNHend |
176 |
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|
177 |
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 |
187 |
latitude-longitude grid. Both grids are supported within the model. |
latitude-longitude grid. Both grids are supported within the model. |
188 |
|
|
189 |
%% CNHbegin |
%% CNHbegin |
190 |
\input{part1/hs_zave_u_figure} |
\input{s_overview/text/hs_zave_u_figure} |
191 |
%% CNHend |
%% CNHend |
192 |
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|
193 |
\subsection{Ocean gyres} |
\subsection{Ocean gyres} |
206 |
increased until the baroclinic instability process is resolved, numerical |
increased until the baroclinic instability process is resolved, numerical |
207 |
solutions of a different and much more realistic kind, can be obtained. |
solutions of a different and much more realistic kind, can be obtained. |
208 |
|
|
209 |
Figure \ref{fig:ocean-gyres} shows the surface temperature and velocity |
Figure \ref{fig:ocean-gyres} shows the surface temperature and |
210 |
field obtained from MITgcm run at $\frac{1}{6}^{\circ }$ horizontal |
velocity field obtained from MITgcm run at $\frac{1}{6}^{\circ }$ |
211 |
resolution on a $lat-lon$ |
horizontal resolution on a \textit{lat-lon} grid in which the pole has |
212 |
grid in which the pole has been rotated by 90$^{\circ }$ on to the equator |
been rotated by $90^{\circ }$ on to the equator (to avoid the |
213 |
(to avoid the converging of meridian in northern latitudes). 21 vertical |
converging of meridian in northern latitudes). 21 vertical levels are |
214 |
levels are used in the vertical with a `lopped cell' representation of |
used in the vertical with a `lopped cell' representation of |
215 |
topography. The development and propagation of anomalously warm and cold |
topography. The development and propagation of anomalously warm and |
216 |
eddies can be clearly seen in the Gulf Stream region. The transport of |
cold eddies can be clearly seen in the Gulf Stream region. The |
217 |
warm water northward by the mean flow of the Gulf Stream is also clearly |
transport of warm water northward by the mean flow of the Gulf Stream |
218 |
visible. |
is also clearly visible. |
219 |
|
|
220 |
%% CNHbegin |
%% CNHbegin |
221 |
\input{part1/atl6_figure} |
\input{s_overview/text/atl6_figure} |
222 |
%% CNHend |
%% CNHend |
223 |
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224 |
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227 |
<!-- CMIREDIR:global_ocean_circulation: --> |
<!-- CMIREDIR:global_ocean_circulation: --> |
228 |
\end{rawhtml} |
\end{rawhtml} |
229 |
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|
230 |
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 |
231 |
the surface of a 4$^{\circ }$ |
currents at the surface of a $4^{\circ }$ global ocean model run with |
232 |
global ocean model run with 15 vertical levels. Lopped cells are used to |
15 vertical levels. Lopped cells are used to represent topography on a |
233 |
represent topography on a regular $lat-lon$ grid extending from 70$^{\circ |
regular \textit{lat-lon} grid extending from $70^{\circ }N$ to |
234 |
}N $ to 70$^{\circ }S$. The model is driven using monthly-mean winds with |
$70^{\circ }S$. The model is driven using monthly-mean winds with |
235 |
mixed boundary conditions on temperature and salinity at the surface. The |
mixed boundary conditions on temperature and salinity at the surface. |
236 |
transfer properties of ocean eddies, convection and mixing is parameterized |
The transfer properties of ocean eddies, convection and mixing is |
237 |
in this model. |
parameterized in this model. |
238 |
|
|
239 |
Figure \ref{fig:large-scale-circ} (bottom) shows the meridional overturning |
Figure \ref{fig:large-scale-circ} (bottom) shows the meridional overturning |
240 |
circulation of the global ocean in Sverdrups. |
circulation of the global ocean in Sverdrups. |
241 |
|
|
242 |
%%CNHbegin |
%%CNHbegin |
243 |
\input{part1/global_circ_figure} |
\input{s_overview/text/global_circ_figure} |
244 |
%%CNHend |
%%CNHend |
245 |
|
|
246 |
\subsection{Convection and mixing over topography} |
\subsection{Convection and mixing over topography} |
263 |
instability of the along-slope current. |
instability of the along-slope current. |
264 |
|
|
265 |
%%CNHbegin |
%%CNHbegin |
266 |
\input{part1/convect_and_topo} |
\input{s_overview/text/convect_and_topo} |
267 |
%%CNHend |
%%CNHend |
268 |
|
|
269 |
\subsection{Boundary forced internal waves} |
\subsection{Boundary forced internal waves} |
285 |
nonhydrostatic dynamics. |
nonhydrostatic dynamics. |
286 |
|
|
287 |
%%CNHbegin |
%%CNHbegin |
288 |
\input{part1/boundary_forced_waves} |
\input{s_overview/text/boundary_forced_waves} |
289 |
%%CNHend |
%%CNHend |
290 |
|
|
291 |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
\subsection{Parameter sensitivity using the adjoint of MITgcm} |
297 |
`automatic adjoint compiler'. These can be used in parameter sensitivity and |
`automatic adjoint compiler'. These can be used in parameter sensitivity and |
298 |
data assimilation studies. |
data assimilation studies. |
299 |
|
|
300 |
As one example of application of the MITgcm adjoint, Figure \ref{fig:hf-sensitivity} |
As one example of application of the MITgcm adjoint, Figure |
301 |
maps the gradient $\frac{\partial J}{\partial \mathcal{H}}$where $J$ is the magnitude |
\ref{fig:hf-sensitivity} maps the gradient $\frac{\partial J}{\partial |
302 |
of the overturning stream-function shown in figure \ref{fig:large-scale-circ} |
\mathcal{H}}$where $J$ is the magnitude of the overturning |
303 |
at 60$^{\circ }$N and $ |
stream-function shown in figure \ref{fig:large-scale-circ} at |
304 |
\mathcal{H}(\lambda,\varphi)$ is the mean, local air-sea heat flux over |
$60^{\circ }N$ and $ \mathcal{H}(\lambda,\varphi)$ is the mean, local |
305 |
a 100 year period. We see that $J$ is |
air-sea heat flux over a 100 year period. We see that $J$ is sensitive |
306 |
sensitive to heat fluxes over the Labrador Sea, one of the important sources |
to heat fluxes over the Labrador Sea, one of the important sources of |
307 |
of deep water for the thermohaline circulations. This calculation also |
deep water for the thermohaline circulations. This calculation also |
308 |
yields sensitivities to all other model parameters. |
yields sensitivities to all other model parameters. |
309 |
|
|
310 |
%%CNHbegin |
%%CNHbegin |
311 |
\input{part1/adj_hf_ocean_figure} |
\input{s_overview/text/adj_hf_ocean_figure} |
312 |
%%CNHend |
%%CNHend |
313 |
|
|
314 |
\subsection{Global state estimation of the ocean} |
\subsection{Global state estimation of the ocean} |
329 |
1992-1997. |
1992-1997. |
330 |
|
|
331 |
%% CNHbegin |
%% CNHbegin |
332 |
\input{part1/assim_figure} |
\input{s_overview/text/assim_figure} |
333 |
%% CNHend |
%% CNHend |
334 |
|
|
335 |
\subsection{Ocean biogeochemical cycles} |
\subsection{Ocean biogeochemical cycles} |
337 |
<!-- CMIREDIR:ocean_biogeo_cycles: --> |
<!-- CMIREDIR:ocean_biogeo_cycles: --> |
338 |
\end{rawhtml} |
\end{rawhtml} |
339 |
|
|
340 |
MITgcm is being used to study global biogeochemical cycles in the ocean. For |
MITgcm is being used to study global biogeochemical cycles in the |
341 |
example one can study the effects of interannual changes in meteorological |
ocean. For example one can study the effects of interannual changes in |
342 |
forcing and upper ocean circulation on the fluxes of carbon dioxide and |
meteorological forcing and upper ocean circulation on the fluxes of |
343 |
oxygen between the ocean and atmosphere. Figure \ref{fig:biogeo} shows |
carbon dioxide and oxygen between the ocean and atmosphere. Figure |
344 |
the annual air-sea flux of oxygen and its relation to density outcrops in |
\ref{fig:biogeo} shows the annual air-sea flux of oxygen and its |
345 |
the southern oceans from a single year of a global, interannually varying |
relation to density outcrops in the southern oceans from a single year |
346 |
simulation. The simulation is run at $1^{\circ}\times1^{\circ}$ resolution |
of a global, interannually varying simulation. The simulation is run |
347 |
telescoping to $\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not shown). |
at $1^{\circ}\times1^{\circ}$ resolution telescoping to |
348 |
|
$\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not |
349 |
|
shown). |
350 |
|
|
351 |
%%CNHbegin |
%%CNHbegin |
352 |
\input{part1/biogeo_figure} |
\input{s_overview/text/biogeo_figure} |
353 |
%%CNHend |
%%CNHend |
354 |
|
|
355 |
\subsection{Simulations of laboratory experiments} |
\subsection{Simulations of laboratory experiments} |
367 |
stratification of the ACC. |
stratification of the ACC. |
368 |
|
|
369 |
%%CNHbegin |
%%CNHbegin |
370 |
\input{part1/lab_figure} |
\input{s_overview/text/lab_figure} |
371 |
%%CNHend |
%%CNHend |
372 |
|
|
|
% $Header$ |
|
|
% $Name$ |
|
|
|
|
373 |
\section{Continuous equations in `r' coordinates} |
\section{Continuous equations in `r' coordinates} |
374 |
\begin{rawhtml} |
\begin{rawhtml} |
375 |
<!-- CMIREDIR:z-p_isomorphism: --> |
<!-- CMIREDIR:z-p_isomorphism: --> |
387 |
\ref{fig:isomorphic-equations}). |
\ref{fig:isomorphic-equations}). |
388 |
|
|
389 |
%%CNHbegin |
%%CNHbegin |
390 |
\input{part1/zandpcoord_figure.tex} |
\input{s_overview/text/zandpcoord_figure.tex} |
391 |
%%CNHend |
%%CNHend |
392 |
|
|
393 |
The state of the fluid at any time is characterized by the distribution of |
The state of the fluid at any time is characterized by the distribution of |
401 |
see figure \ref{fig:zandp-vert-coord}. |
see figure \ref{fig:zandp-vert-coord}. |
402 |
|
|
403 |
%%CNHbegin |
%%CNHbegin |
404 |
\input{part1/vertcoord_figure.tex} |
\input{s_overview/text/vertcoord_figure.tex} |
405 |
%%CNHend |
%%CNHend |
406 |
|
|
407 |
\begin{equation} |
\begin{equation} |
652 |
|
|
653 |
\subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and |
\subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and |
654 |
Non-hydrostatic forms} |
Non-hydrostatic forms} |
655 |
|
\label{sec:all_hydrostatic_forms} |
656 |
\begin{rawhtml} |
\begin{rawhtml} |
657 |
<!-- CMIREDIR:non_hydrostatic: --> |
<!-- CMIREDIR:non_hydrostatic: --> |
658 |
\end{rawhtml} |
\end{rawhtml} |
761 |
OPERATORS. |
OPERATORS. |
762 |
|
|
763 |
%%CNHbegin |
%%CNHbegin |
764 |
\input{part1/sphere_coord_figure.tex} |
\input{s_overview/text/sphere_coord_figure.tex} |
765 |
%%CNHend |
%%CNHend |
766 |
|
|
767 |
\subsubsection{Shallow atmosphere approximation} |
\subsubsection{Shallow atmosphere approximation} |
768 |
|
|
769 |
Most models are based on the `hydrostatic primitive equations' (HPE's) in |
Most models are based on the `hydrostatic primitive equations' (HPE's) |
770 |
which the vertical momentum equation is reduced to a statement of |
in which the vertical momentum equation is reduced to a statement of |
771 |
hydrostatic balance and the `traditional approximation' is made in which the |
hydrostatic balance and the `traditional approximation' is made in |
772 |
Coriolis force is treated approximately and the shallow atmosphere |
which the Coriolis force is treated approximately and the shallow |
773 |
approximation is made.\ The MITgcm need not make the `traditional |
atmosphere approximation is made. MITgcm need not make the |
774 |
approximation'. To be able to support consistent non-hydrostatic forms the |
`traditional approximation'. To be able to support consistent |
775 |
shallow atmosphere approximation can be relaxed - when dividing through by $ |
non-hydrostatic forms the shallow atmosphere approximation can be |
776 |
r $ in, for example, (\ref{eq:gu-speherical}), we do not replace $r$ by $a$, |
relaxed - when dividing through by $ r $ in, for example, |
777 |
the radius of the earth. |
(\ref{eq:gu-speherical}), we do not replace $r$ by $a$, the radius of |
778 |
|
the earth. |
779 |
|
|
780 |
\subsubsection{Hydrostatic and quasi-hydrostatic forms} |
\subsubsection{Hydrostatic and quasi-hydrostatic forms} |
781 |
\label{sec:hydrostatic_and_quasi-hydrostatic_forms} |
\label{sec:hydrostatic_and_quasi-hydrostatic_forms} |
812 |
|
|
813 |
\subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms} |
\subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms} |
814 |
|
|
815 |
The MIT model presently supports a full non-hydrostatic ocean isomorph, but |
MITgcm presently supports a full non-hydrostatic ocean isomorph, but |
816 |
only a quasi-non-hydrostatic atmospheric isomorph. |
only a quasi-non-hydrostatic atmospheric isomorph. |
817 |
|
|
818 |
\paragraph{Non-hydrostatic Ocean} |
\paragraph{Non-hydrostatic Ocean} |
882 |
stepping forward the vertical momentum equation. |
stepping forward the vertical momentum equation. |
883 |
|
|
884 |
%%CNHbegin |
%%CNHbegin |
885 |
\input{part1/solution_strategy_figure.tex} |
\input{s_overview/text/solution_strategy_figure.tex} |
886 |
%%CNHend |
%%CNHend |
887 |
|
|
888 |
There is no penalty in implementing \textbf{QH} over \textbf{HPE} except, of |
There is no penalty in implementing \textbf{QH} over \textbf{HPE} except, of |
1071 |
|
|
1072 |
The mixing terms for the temperature and salinity equations have a similar |
The mixing terms for the temperature and salinity equations have a similar |
1073 |
form to that of momentum except that the diffusion tensor can be |
form to that of momentum except that the diffusion tensor can be |
1074 |
non-diagonal and have varying coefficients. $\qquad $ |
non-diagonal and have varying coefficients. |
1075 |
\begin{equation} |
\begin{equation} |
1076 |
D_{T,S}=\nabla .[\underline{\underline{K}}\nabla (T,S)]+K_{4}\nabla |
D_{T,S}=\nabla .[\underline{\underline{K}}\nabla (T,S)]+K_{4}\nabla |
1077 |
_{h}^{4}(T,S) \label{eq:diffusion} |
_{h}^{4}(T,S) \label{eq:diffusion} |
1120 |
Tangent linear and adjoint counterparts of the forward model are described |
Tangent linear and adjoint counterparts of the forward model are described |
1121 |
in Chapter 5. |
in Chapter 5. |
1122 |
|
|
|
% $Header$ |
|
|
% $Name$ |
|
|
|
|
1123 |
\section{Appendix ATMOSPHERE} |
\section{Appendix ATMOSPHERE} |
1124 |
|
|
1125 |
\subsection{Hydrostatic Primitive Equations for the Atmosphere in pressure |
\subsection{Hydrostatic Primitive Equations for the Atmosphere in pressure |
1139 |
c_{v}\frac{DT}{Dt}+p\frac{D\alpha }{Dt} &=&\mathcal{Q} \label{eq:atmos-heat} |
c_{v}\frac{DT}{Dt}+p\frac{D\alpha }{Dt} &=&\mathcal{Q} \label{eq:atmos-heat} |
1140 |
\end{eqnarray} |
\end{eqnarray} |
1141 |
where $\vec{\mathbf{v}}_{h}=(u,v,0)$ is the `horizontal' (on pressure |
where $\vec{\mathbf{v}}_{h}=(u,v,0)$ is the `horizontal' (on pressure |
1142 |
surfaces) component of velocity,$\frac{D}{Dt}=\vec{\mathbf{v}}_{h}\cdot |
surfaces) component of velocity, $\frac{D}{Dt}=\frac{\partial}{\partial t} |
1143 |
\mathbf{\nabla }_{p}+\omega \frac{\partial }{\partial p}$ is the total |
+\vec{\mathbf{v}}_{h}\cdot \mathbf{\nabla }_{p}+\omega \frac{\partial }{\partial p}$ |
1144 |
derivative, $f=2\Omega \sin \varphi$ is the Coriolis parameter, $\phi =gz$ is |
is the total derivative, $f=2\Omega \sin \varphi$ is the Coriolis parameter, |
1145 |
the geopotential, $\alpha =1/\rho $ is the specific volume, $\omega =\frac{Dp |
$\phi =gz$ is the geopotential, $\alpha =1/\rho $ is the specific volume, |
1146 |
}{Dt}$ is the vertical velocity in the $p-$coordinate. Equation(\ref |
$\omega =\frac{Dp }{Dt}$ is the vertical velocity in the $p-$coordinate. |
1147 |
{eq:atmos-heat}) is the first law of thermodynamics where internal energy $ |
Equation(\ref {eq:atmos-heat}) is the first law of thermodynamics where internal |
1148 |
e=c_{v}T$, $T$ is temperature, $Q$ is the rate of heating per unit mass and $ |
energy $e=c_{v}T$, $T$ is temperature, $Q$ is the rate of heating per unit mass |
1149 |
p\frac{D\alpha }{Dt}$ is the work done by the fluid in compressing. |
and $p\frac{D\alpha }{Dt}$ is the work done by the fluid in compressing. |
1150 |
|
|
1151 |
It is convenient to cast the heat equation in terms of potential temperature |
It is convenient to cast the heat equation in terms of potential temperature |
1152 |
$\theta $ so that it looks more like a generic conservation law. |
$\theta $ so that it looks more like a generic conservation law. |
1246 |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } |
\frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi } |
1247 |
\end{eqnarray} |
\end{eqnarray} |
1248 |
|
|
|
% $Header$ |
|
|
% $Name$ |
|
|
|
|
1249 |
\section{Appendix OCEAN} |
\section{Appendix OCEAN} |
1250 |
|
|
1251 |
\subsection{Equations of motion for the ocean} |
\subsection{Equations of motion for the ocean} |
1460 |
_{nh}=0$ form of these equations that are used throughout the ocean modeling |
_{nh}=0$ form of these equations that are used throughout the ocean modeling |
1461 |
community and referred to as the primitive equations (HPE). |
community and referred to as the primitive equations (HPE). |
1462 |
|
|
|
% $Header$ |
|
|
% $Name$ |
|
|
|
|
1463 |
\section{Appendix:OPERATORS} |
\section{Appendix:OPERATORS} |
1464 |
|
|
1465 |
\subsection{Coordinate systems} |
\subsection{Coordinate systems} |
1474 |
\end{equation*} |
\end{equation*} |
1475 |
|
|
1476 |
\begin{equation*} |
\begin{equation*} |
1477 |
v=r\frac{D\varphi }{Dt}\qquad |
v=r\frac{D\varphi }{Dt} |
1478 |
\end{equation*} |
\end{equation*} |
|
$\qquad \qquad \qquad \qquad $ |
|
1479 |
|
|
1480 |
\begin{equation*} |
\begin{equation*} |
1481 |
\dot{r}=\frac{Dr}{Dt} |
\dot{r}=\frac{Dr}{Dt} |
1485 |
distance of the particle from the center of the earth, $\Omega $ is the |
distance of the particle from the center of the earth, $\Omega $ is the |
1486 |
angular speed of rotation of the Earth and $D/Dt$ is the total derivative. |
angular speed of rotation of the Earth and $D/Dt$ is the total derivative. |
1487 |
|
|
1488 |
The `grad' ($\nabla $) and `div' ($\nabla $.) operators are defined by, in |
The `grad' ($\nabla $) and `div' ($\nabla\cdot$) operators are defined by, in |
1489 |
spherical coordinates: |
spherical coordinates: |
1490 |
|
|
1491 |
\begin{equation*} |
\begin{equation*} |
1495 |
\end{equation*} |
\end{equation*} |
1496 |
|
|
1497 |
\begin{equation*} |
\begin{equation*} |
1498 |
\nabla .v\equiv \frac{1}{r\cos \varphi }\left\{ \frac{\partial u}{\partial |
\nabla\cdot v\equiv \frac{1}{r\cos \varphi }\left\{ \frac{\partial u}{\partial |
1499 |
\lambda }+\frac{\partial }{\partial \varphi }\left( v\cos \varphi \right) \right\} |
\lambda }+\frac{\partial }{\partial \varphi }\left( v\cos \varphi \right) \right\} |
1500 |
+\frac{1}{r^{2}}\frac{\partial \left( r^{2}\dot{r}\right) }{\partial r} |
+\frac{1}{r^{2}}\frac{\partial \left( r^{2}\dot{r}\right) }{\partial r} |
1501 |
\end{equation*} |
\end{equation*} |