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revision 1.13 by cnh, Mon Nov 19 19:58:20 2001 UTC revision 1.30 by jmc, Wed May 11 18:45:43 2016 UTC
# Line 34  Line 34 
34    
35  % Section: Overview  % Section: Overview
36    
37  % $Header$  This document provides the reader with the information necessary to
 % $Name$  
   
 \section{Introduction}  
   
 This documentation 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
40  numerical algorithms the model employs and a description of the associated  numerical algorithms the model employs and a description of the associated
# Line 49  are available. A number of examples illu Line 44  are available. A number of examples illu
44  both process and general circulation studies of the atmosphere and ocean are  both process and general circulation studies of the atmosphere and ocean are
45  also presented.  also presented.
46    
47    \section{Introduction}
48    \begin{rawhtml}
49    <!-- CMIREDIR:innovations: -->
50    \end{rawhtml}
51    
52    
53  MITgcm has a number of novel aspects:  MITgcm has a number of novel aspects:
54    
55  \begin{itemize}  \begin{itemize}
# Line 57  hydrodynamical kernel is used to drive f Line 58  hydrodynamical kernel is used to drive f
58  models - see fig \ref{fig:onemodel}  models - see fig \ref{fig:onemodel}
59    
60  %% CNHbegin  %% CNHbegin
61  \input{part1/one_model_figure}  \input{s_overview/text/one_model_figure}
62  %% CNHend  %% CNHend
63    
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    
67  %% CNHbegin  %% CNHbegin
68  \input{part1/all_scales_figure}  \input{s_overview/text/all_scales_figure}
69  %% CNHend  %% CNHend
70    
71  \item finite volume techniques are employed yielding an intuitive  \item finite volume techniques are employed yielding an intuitive
# Line 72  discretization and support for the treat Line 73  discretization and support for the treat
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    
75  %% CNHbegin  %% CNHbegin
76  \input{part1/fvol_figure}  \input{s_overview/text/fvol_figure}
77  %% CNHend  %% CNHend
78    
79  \item tangent linear and adjoint counterparts are automatically maintained  \item tangent linear and adjoint counterparts are automatically maintained
# Line 83  studies. Line 84  studies.
84  computational platforms.  computational platforms.
85  \end{itemize}  \end{itemize}
86    
 Key publications reporting on and charting the development of the model are:  
87    
88  \begin{verbatim}  Key publications reporting on and charting the development of the model are
89    \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    
92    \begin{verbatim}
93  Hill, C. and J. Marshall, (1995)  Hill, C. and J. Marshall, (1995)
94  Application of a Parallel Navier-Stokes Model to Ocean Circulation in  Application of a Parallel Navier-Stokes Model to Ocean Circulation in
95  Parallel Computational Fluid Dynamics  Parallel Computational Fluid Dynamics
# Line 95  and Results Using Parallel Computers, 54 Line 98  and Results Using Parallel Computers, 54
98  Elsevier Science B.V.: New York  Elsevier Science B.V.: New York
99    
100  Marshall, J., C. Hill, L. Perelman, and A. Adcroft, (1997)  Marshall, J., C. Hill, L. Perelman, and A. Adcroft, (1997)
101  Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling,  Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling
102  J. Geophysical Res., 102(C3), 5733-5752.  J. Geophysical Res., 102(C3), 5733-5752.
103    
104  Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, (1997)  Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, (1997)
# Line 119  Mon. Wea. Rev. Vol 127, pages 1928-1936 Line 122  Mon. Wea. Rev. Vol 127, pages 1928-1936
122    
123  Hill, C, Adcroft,A., Jamous,D., and J. Marshall, (1999)  Hill, C, Adcroft,A., Jamous,D., and J. Marshall, (1999)
124  A Strategy for Terascale Climate Modeling.  A Strategy for Terascale Climate Modeling.
125  In Proceedings of the Eight ECMWF Workshop on the Use of Parallel Processors  In Proceedings of the Eighth ECMWF Workshop on the Use of Parallel Processors
126  in Meteorology  in Meteorology, pages 406-425
127    World Scientific Publishing Co: UK
128    
129  Marotzke, J, Giering,R., Zhang, K.Q., Stammer,D., Hill,C., and T.Lee, (1999)  Marotzke, J, Giering,R., Zhang, K.Q., Stammer,D., Hill,C., and T.Lee, (1999)
130  Construction of the adjoint MIT ocean general circulation model and  Construction of the adjoint MIT ocean general circulation model and
131  application to Atlantic heat transport variability  application to Atlantic heat transport variability
132  J. Geophysical Res., 104(C12), 29,529-29,547.  J. Geophysical Res., 104(C12), 29,529-29,547.
133    
   
134  \end{verbatim}  \end{verbatim}
135    
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    
 % $Header$  
 % $Name$  
   
139  \section{Illustrations of the model in action}  \section{Illustrations of the model in action}
140    
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
# Line 150  running Linux, together with a FORTRAN\ Line 150  running Linux, together with a FORTRAN\
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}
153    \begin{rawhtml}
154    <!-- CMIREDIR:atmospheric_example: -->
155    \end{rawhtml}
156    
157    
158    
159  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,
160  both atmospheric and oceanographic flows at both small and large scales.  both atmospheric and oceanographic flows at both small and large scales.
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,
# Line 166  in Held and Suarez; 1994 designed to tes Line 171  in Held and Suarez; 1994 designed to tes
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    
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
# Line 182  cube-sphere grid and the flow calculated Line 187  cube-sphere grid and the flow calculated
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    
193  \subsection{Ocean gyres}  \subsection{Ocean gyres}
194    \begin{rawhtml}
195    <!-- CMIREDIR:oceanic_example: -->
196    \end{rawhtml}
197    \begin{rawhtml}
198    <!-- CMIREDIR:ocean_gyres: -->
199    \end{rawhtml}
200    
201  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
202  atmosphere. Ocean eddies play an important role in modifying the  atmosphere. Ocean eddies play an important role in modifying the
# Line 195  diffusive patterns of ocean currents. Bu Line 206  diffusive patterns of ocean currents. Bu
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    
224    
225  \subsection{Global ocean circulation}  \subsection{Global ocean circulation}
226    \begin{rawhtml}
227  Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean currents at  <!-- CMIREDIR:global_ocean_circulation: -->
228  the surface of a 4$^{\circ }$  \end{rawhtml}
229  global ocean model run with 15 vertical levels. Lopped cells are used to  
230  represent topography on a regular $lat-lon$ grid extending from 70$^{\circ  Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean
231  }N $ to 70$^{\circ }S$. The model is driven using monthly-mean winds with  currents at the surface of a $4^{\circ }$ global ocean model run with
232  mixed boundary conditions on temperature and salinity at the surface. The  15 vertical levels. Lopped cells are used to represent topography on a
233  transfer properties of ocean eddies, convection and mixing is parameterized  regular \textit{lat-lon} grid extending from $70^{\circ }N$ to
234  in this model.  $70^{\circ }S$. The model is driven using monthly-mean winds with
235    mixed boundary conditions on temperature and salinity at the surface.
236    The transfer properties of ocean eddies, convection and mixing is
237    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}
247    \begin{rawhtml}
248    <!-- CMIREDIR:mixing_over_topography: -->
249    \end{rawhtml}
250    
251    
252  Dense plumes generated by localized cooling on the continental shelf of the  Dense plumes generated by localized cooling on the continental shelf of the
253  ocean may be influenced by rotation when the deformation radius is smaller  ocean may be influenced by rotation when the deformation radius is smaller
# Line 245  strong, and replaced by lateral entrainm Line 263  strong, and replaced by lateral entrainm
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}
270    \begin{rawhtml}
271    <!-- CMIREDIR:boundary_forced_internal_waves: -->
272    \end{rawhtml}
273    
274  The unique ability of MITgcm to treat non-hydrostatic dynamics in the  The unique ability of MITgcm to treat non-hydrostatic dynamics in the
275  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
# Line 264  using MITgcm's finite volume spatial dis Line 285  using MITgcm's finite volume spatial dis
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}
292    \begin{rawhtml}
293    <!-- CMIREDIR:parameter_sensitivity: -->
294    \end{rawhtml}
295    
296  Forward and tangent linear counterparts of MITgcm are supported using an  Forward and tangent linear counterparts of MITgcm are supported using an
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}
315    \begin{rawhtml}
316    <!-- CMIREDIR:global_state_estimation: -->
317    \end{rawhtml}
318    
319    
320  An important application of MITgcm is in state estimation of the global  An important application of MITgcm is in state estimation of the global
321  ocean circulation. An appropriately defined `cost function', which measures  ocean circulation. An appropriately defined `cost function', which measures
322  the departure of the model from observations (both remotely sensed and  the departure of the model from observations (both remotely sensed and
323  in-situ) over an interval of time, is minimized by adjusting `control  in-situ) over an interval of time, is minimized by adjusting `control
324  parameters' such as air-sea fluxes, the wind field, the initial conditions  parameters' such as air-sea fluxes, the wind field, the initial conditions
325  etc. Figure \ref{fig:assimilated-globes} shows an estimate of the time-mean  etc. Figure \ref{fig:assimilated-globes} shows the large scale planetary
326  surface elevation of the ocean obtained by bringing the model in to  circulation and a Hopf-Muller plot of Equatorial sea-surface height.
327    Both are obtained from assimilation bringing the model in to
328  consistency with altimetric and in-situ observations over the period  consistency with altimetric and in-situ observations over the period
329  1992-1997. {\bf CHANGE THIS TEXT - FIG FROM PATRICK/CARL/DETLEF}  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}
336    \begin{rawhtml}
337  MITgcm is being used to study global biogeochemical cycles in the ocean. For  <!-- CMIREDIR:ocean_biogeo_cycles: -->
338  example one can study the effects of interannual changes in meteorological  \end{rawhtml}
339  forcing and upper ocean circulation on the fluxes of carbon dioxide and  
340  oxygen between the ocean and atmosphere. Figure \ref{fig:biogeo} shows  MITgcm is being used to study global biogeochemical cycles in the
341  the annual air-sea flux of oxygen and its relation to density outcrops in  ocean. For example one can study the effects of interannual changes in
342  the southern oceans from a single year of a global, interannually varying  meteorological forcing and upper ocean circulation on the fluxes of
343  simulation. The simulation is run at $1^{\circ}\times1^{\circ}$ resolution  carbon dioxide and oxygen between the ocean and atmosphere. Figure
344  telescoping to $\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not shown).  \ref{fig:biogeo} shows the annual air-sea flux of oxygen and its
345    relation to density outcrops in the southern oceans from a single year
346    of a global, interannually varying simulation. The simulation is run
347    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}
356    \begin{rawhtml}
357    <!-- CMIREDIR:classroom_exp: -->
358    \end{rawhtml}
359    
360  Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a  Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a
361  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
362  initially homogeneous tank of water ($1m$ in diameter) is driven from its  initially homogeneous tank of water ($1m$ in diameter) is driven from its
363  free surface by a rotating heated disk. The combined action of mechanical  free surface by a rotating heated disk. The combined action of mechanical
364  and thermal forcing creates a lens of fluid which becomes baroclinically  and thermal forcing creates a lens of fluid which becomes baroclinically
# Line 330  arrested by its instability in a process Line 367  arrested by its instability in a process
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}
375    <!-- CMIREDIR:z-p_isomorphism: -->
376    \end{rawhtml}
377    
378  To render atmosphere and ocean models from one dynamical core we exploit  To render atmosphere and ocean models from one dynamical core we exploit
379  `isomorphisms' between equation sets that govern the evolution of the  `isomorphisms' between equation sets that govern the evolution of the
# Line 345  One system of hydrodynamical equations i Line 382  One system of hydrodynamical equations i
382  and encoded. The model variables have different interpretations depending on  and encoded. The model variables have different interpretations depending on
383  whether the atmosphere or ocean is being studied. Thus, for example, the  whether the atmosphere or ocean is being studied. Thus, for example, the
384  vertical coordinate `$r$' is interpreted as pressure, $p$, if we are  vertical coordinate `$r$' is interpreted as pressure, $p$, if we are
385  modeling the atmosphere (left hand side of figure \ref{fig:isomorphic-equations})  modeling the atmosphere (right hand side of figure \ref{fig:isomorphic-equations})
386  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
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
# Line 364  kinematic boundary conditions can be app Line 401  kinematic boundary conditions can be app
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}
408  \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}}
409  \right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}}  \right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}}
410  \text{ horizontal mtm} \label{eq:horizontal_mtm}  \text{ horizontal mtm} \label{eq:horizontal_mtm}
411  \end{equation*}  \end{equation}
412    
413  \begin{equation}  \begin{equation}
414  \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{
# Line 470  in later chapters. Line 507  in later chapters.
507  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}):
508    
509  \begin{equation}  \begin{equation}
510  \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)}
511  \label{eq:fixedbc}  \label{eq:fixedbc}
512  \end{equation}  \end{equation}
513    
514  \begin{equation}  \begin{equation}
515  \dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \  \dot{r}=\frac{Dr}{Dt} \text{\ at\ } r=R_{moving}\text{ \
516  (ocean surface,bottom of the atmosphere)}  \label{eq:movingbc}  (ocean surface,bottom of the atmosphere)}  \label{eq:movingbc}
517  \end{equation}  \end{equation}
518    
# Line 569  The boundary conditions at top and botto Line 606  The boundary conditions at top and botto
606  atmosphere)}  \label{eq:moving-bc-atmos}  atmosphere)}  \label{eq:moving-bc-atmos}
607  \end{eqnarray}  \end{eqnarray}
608    
609  Then the (hydrostatic form of) equations (\ref{eq:horizontal_mtm}-\ref{eq:humidity_salt})  Then the (hydrostatic form of) equations
610  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
611  coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}).  set of atmospheric equations which, for convenience, are written out
612    in $p$ coordinates in Appendix Atmosphere - see
613    eqs(\ref{eq:atmos-prime}).
614    
615  \subsection{Ocean}  \subsection{Ocean}
616    
# Line 613  which, for convenience, are written out Line 652  which, for convenience, are written out
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}
657    <!-- CMIREDIR:non_hydrostatic: -->
658    \end{rawhtml}
659    
660    
661  Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms:  Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms:
662    
# Line 620  Let us separate $\phi $ in to surface, h Line 664  Let us separate $\phi $ in to surface, h
664  \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)
665  \label{eq:phi-split}  \label{eq:phi-split}
666  \end{equation}  \end{equation}
667  and write eq(\ref{eq:incompressible}) in the form:  %and write eq(\ref{eq:incompressible}) in the form:
668    %                  ^- this eq is missing (jmc) ; replaced with:
669    and write eq( \ref{eq:horizontal_mtm}) in the form:
670    
671  \begin{equation}  \begin{equation}
672  \frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi  \frac{\partial \vec{\mathbf{v}_{h}}}{\partial t}+\mathbf{\nabla }_{h}\phi
# Line 715  Grad and div operators in spherical coor Line 761  Grad and div operators in spherical coor
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}
# Line 765  et.al., 1997a. As in \textbf{HPE }only a Line 812  et.al., 1997a. As in \textbf{HPE }only a
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}
# Line 835  stepping forward the horizontal momentum Line 882  stepping forward the horizontal momentum
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
# Line 1024  friction. These coefficients are the sam Line 1071  friction. These coefficients are the sam
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}
# Line 1050  salinity ... ). Line 1097  salinity ... ).
1097    
1098  \subsection{Vector invariant form}  \subsection{Vector invariant form}
1099    
1100  For some purposes it is advantageous to write momentum advection in eq(\ref  For some purposes it is advantageous to write momentum advection in
1101  {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
1102    (so-called) `vector invariant' form:
1103    
1104  \begin{equation}  \begin{equation}
1105  \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}
# Line 1072  to discretize the model. Line 1120  to discretize the model.
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
# Line 1094  p\alpha &=&RT  \label{eq:atmos-eos} \\ Line 1139  p\alpha &=&RT  \label{eq:atmos-eos} \\
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.
# Line 1162  In $p$-coordinates, the upper boundary a Line 1207  In $p$-coordinates, the upper boundary a
1207  surface ($\phi $ is imposed and $\omega \neq 0$).  surface ($\phi $ is imposed and $\omega \neq 0$).
1208    
1209  \subsubsection{Splitting the geo-potential}  \subsubsection{Splitting the geo-potential}
1210    \label{sec:hpe-p-geo-potential-split}
1211    
1212  For the purposes of initialization and reducing round-off errors, the model  For the purposes of initialization and reducing round-off errors, the model
1213  deals with perturbations from reference (or ``standard'') profiles. For  deals with perturbations from reference (or ``standard'') profiles. For
# Line 1191  _{o}(p_{o})=g~Z_{topo}$, defined: Line 1237  _{o}(p_{o})=g~Z_{topo}$, defined:
1237  The final form of the HPE's in p coordinates is then:  The final form of the HPE's in p coordinates is then:
1238  \begin{eqnarray}  \begin{eqnarray}
1239  \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}}
1240  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}}
1241    \label{eq:atmos-prime} \\
1242  \frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\  \frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\
1243  \mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{  \mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{
1244  \partial p} &=&0 \\  \partial p} &=&0 \\
# Line 1199  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime } Line 1246  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime }
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}
# Line 1237  _{\theta ,p}\frac{DS}{Dt}+\left. \frac{\ Line 1281  _{\theta ,p}\frac{DS}{Dt}+\left. \frac{\
1281  _{\theta ,S}\frac{Dp}{Dt}  \label{EOSexpansion}  _{\theta ,S}\frac{Dp}{Dt}  \label{EOSexpansion}
1282  \end{equation}  \end{equation}
1283    
1284  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
1285  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
1286    \ref{eq-zns-cont} gives:
1287  \begin{equation}  \begin{equation}
1288  \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{
1289  v}}+\partial _{z}w\approx 0  \label{eq-zns-pressure}  v}}+\partial _{z}w\approx 0  \label{eq-zns-pressure}
# Line 1415  the perturbation density. Nevertheless, Line 1460  the perturbation density. Nevertheless,
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}
# Line 1432  u=r\cos \varphi \frac{D\lambda }{Dt} Line 1474  u=r\cos \varphi \frac{D\lambda }{Dt}
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}
# Line 1444  Here $\varphi $ is the latitude, $\lambd Line 1485  Here $\varphi $ is the latitude, $\lambd
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*}
# Line 1454  spherical coordinates: Line 1495  spherical coordinates:
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*}

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