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revision 1.5 by adcroft, Mon Oct 15 19:34:28 2001 UTC revision 1.20 by jmc, Fri Oct 15 14:44:25 2004 UTC
# Line 37  Line 37 
37  % $Header$  % $Header$
38  % $Name$  % $Name$
39    
40  \section{Introduction}  This document provides the reader with the information necessary to
   
 This documentation provides the reader with the information necessary to  
41  carry out numerical experiments using MITgcm. It gives a comprehensive  carry out numerical experiments using MITgcm. It gives a comprehensive
42  description of the continuous equations on which the model is based, the  description of the continuous equations on which the model is based, the
43  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 47  are available. A number of examples illu
47  both process and general circulation studies of the atmosphere and ocean are  both process and general circulation studies of the atmosphere and ocean are
48  also presented.  also presented.
49    
50    \section{Introduction}
51    \begin{rawhtml}
52    <!-- CMIREDIR:innovations: -->
53    \end{rawhtml}
54    
55    
56  MITgcm has a number of novel aspects:  MITgcm has a number of novel aspects:
57    
58  \begin{itemize}  \begin{itemize}
59  \item it can be used to study both atmospheric and oceanic phenomena; one  \item it can be used to study both atmospheric and oceanic phenomena; one
60  hydrodynamical kernel is used to drive forward both atmospheric and oceanic  hydrodynamical kernel is used to drive forward both atmospheric and oceanic
61  models - see fig  models - see fig \ref{fig:onemodel}
 \marginpar{  
 Fig.1 One model}\ref{fig:onemodel}  
62    
63  %% CNHbegin  %% CNHbegin
64  \input{part1/one_model_figure}  \input{part1/one_model_figure}
65  %% CNHend  %% CNHend
66    
67  \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
68  small-scale and large scale processes - see fig  small-scale and large scale processes - see fig \ref{fig:all-scales}
 \marginpar{  
 Fig.2 All scales}\ref{fig:all-scales}  
69    
70  %% CNHbegin  %% CNHbegin
71  \input{part1/all_scales_figure}  \input{part1/all_scales_figure}
# Line 73  Fig.2 All scales}\ref{fig:all-scales} Line 73  Fig.2 All scales}\ref{fig:all-scales}
73    
74  \item finite volume techniques are employed yielding an intuitive  \item finite volume techniques are employed yielding an intuitive
75  discretization and support for the treatment of irregular geometries using  discretization and support for the treatment of irregular geometries using
76  orthogonal curvilinear grids and shaved cells - see fig  orthogonal curvilinear grids and shaved cells - see fig \ref{fig:finite-volumes}
 \marginpar{  
 Fig.3 Finite volumes}\ref{fig:finite-volumes}  
77    
78  %% CNHbegin  %% CNHbegin
79  \input{part1/fvol_figure}  \input{part1/fvol_figure}
# Line 90  computational platforms. Line 88  computational platforms.
88  \end{itemize}  \end{itemize}
89    
90  Key publications reporting on and charting the development of the model are  Key publications reporting on and charting the development of the model are
91  listed in an Appendix.  \cite{hill:95,marshall:97a,marshall:97b,adcroft:97,marshall:98,adcroft:99,hill:99,maro-eta:99}:
92    
93    \begin{verbatim}
94    Hill, C. and J. Marshall, (1995)
95    Application of a Parallel Navier-Stokes Model to Ocean Circulation in
96    Parallel Computational Fluid Dynamics
97    In Proceedings of Parallel Computational Fluid Dynamics: Implementations
98    and Results Using Parallel Computers, 545-552.
99    Elsevier Science B.V.: New York
100    
101    Marshall, J., C. Hill, L. Perelman, and A. Adcroft, (1997)
102    Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling
103    J. Geophysical Res., 102(C3), 5733-5752.
104    
105    Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, (1997)
106    A finite-volume, incompressible Navier Stokes model for studies of the ocean
107    on parallel computers,
108    J. Geophysical Res., 102(C3), 5753-5766.
109    
110    Adcroft, A.J., Hill, C.N. and J. Marshall, (1997)
111    Representation of topography by shaved cells in a height coordinate ocean
112    model
113    Mon Wea Rev, vol 125, 2293-2315
114    
115    Marshall, J., Jones, H. and C. Hill, (1998)
116    Efficient ocean modeling using non-hydrostatic algorithms
117    Journal of Marine Systems, 18, 115-134
118    
119    Adcroft, A., Hill C. and J. Marshall: (1999)
120    A new treatment of the Coriolis terms in C-grid models at both high and low
121    resolutions,
122    Mon. Wea. Rev. Vol 127, pages 1928-1936
123    
124    Hill, C, Adcroft,A., Jamous,D., and J. Marshall, (1999)
125    A Strategy for Terascale Climate Modeling.
126    In Proceedings of the Eighth ECMWF Workshop on the Use of Parallel Processors
127    in Meteorology, pages 406-425
128    World Scientific Publishing Co: UK
129    
130    Marotzke, J, Giering,R., Zhang, K.Q., Stammer,D., Hill,C., and T.Lee, (1999)
131    Construction of the adjoint MIT ocean general circulation model and
132    application to Atlantic heat transport variability
133    J. Geophysical Res., 104(C12), 29,529-29,547.
134    
135    \end{verbatim}
136    
137  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
138  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.
# Line 102  give a feel for the wide range of proble Line 144  give a feel for the wide range of proble
144    
145  The MITgcm has been designed and used to model a wide range of phenomena,  The MITgcm has been designed and used to model a wide range of phenomena,
146  from convection on the scale of meters in the ocean to the global pattern of  from convection on the scale of meters in the ocean to the global pattern of
147  atmospheric winds - see fig.2\ref{fig:all-scales}. To give a flavor of the  atmospheric winds - see figure \ref{fig:all-scales}. To give a flavor of the
148  kinds of problems the model has been used to study, we briefly describe some  kinds of problems the model has been used to study, we briefly describe some
149  of them here. A more detailed description of the underlying formulation,  of them here. A more detailed description of the underlying formulation,
150  numerical algorithm and implementation that lie behind these calculations is  numerical algorithm and implementation that lie behind these calculations is
151  given later. Indeed many of the illustrative examples shown below can be  given later. Indeed many of the illustrative examples shown below can be
152  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
153  running linux, together with a FORTRAN\ 77 compiler) and follow the examples  running Linux, together with a FORTRAN\ 77 compiler) and follow the examples
154  described in detail in the documentation.  described in detail in the documentation.
155    
156  \subsection{Global atmosphere: `Held-Suarez' benchmark}  \subsection{Global atmosphere: `Held-Suarez' benchmark}
157    \begin{rawhtml}
158    <!-- CMIREDIR:atmospheric_example: -->
159    \end{rawhtml}
160    
161    
162    
163  A novel feature of MITgcm is its ability to simulate both atmospheric and  A novel feature of MITgcm is its ability to simulate, using one basic algorithm,
164  oceanographic flows at both small and large scales.  both atmospheric and oceanographic flows at both small and large scales.
165    
166  Fig.E1a.\ref{fig:eddy_cs} shows an instantaneous plot of the 500$mb$  Figure \ref{fig:eddy_cs} shows an instantaneous plot of the 500$mb$
167  temperature field obtained using the atmospheric isomorph of MITgcm run at  temperature field obtained using the atmospheric isomorph of MITgcm run at
168  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
169  (blue) and warm air along an equatorial band (red). Fully developed  (blue) and warm air along an equatorial band (red). Fully developed
# Line 132  there are no mountains or land-sea contr Line 179  there are no mountains or land-sea contr
179  %% CNHend  %% CNHend
180    
181  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
182  globe permitting a uniform gridding and obviated the need to fourier filter.  globe permitting a uniform griding and obviated the need to Fourier filter.
183  The `vector-invariant' form of MITgcm supports any orthogonal curvilinear  The `vector-invariant' form of MITgcm supports any orthogonal curvilinear
184  grid, of which the cubed sphere is just one of many choices.  grid, of which the cubed sphere is just one of many choices.
185    
186  Fig.E1b shows the 5-year mean, zonally averaged potential temperature, zonal  Figure \ref{fig:hs_zave_u} shows the 5-year mean, zonally averaged zonal
187  wind and meridional overturning streamfunction from a 20-level version of  wind from a 20-level configuration of
188  the model. It compares favorable with more conventional spatial  the model. It compares favorable with more conventional spatial
189  discretization approaches.  discretization approaches. The two plots show the field calculated using the
190    cube-sphere grid and the flow calculated using a regular, spherical polar
191  A regular spherical lat-lon grid can also be used.  latitude-longitude grid. Both grids are supported within the model.
192    
193  %% CNHbegin  %% CNHbegin
194  \input{part1/hs_zave_u_figure}  \input{part1/hs_zave_u_figure}
195  %% CNHend  %% CNHend
196    
197  \subsection{Ocean gyres}  \subsection{Ocean gyres}
198    \begin{rawhtml}
199    <!-- CMIREDIR:oceanic_example: -->
200    \end{rawhtml}
201    \begin{rawhtml}
202    <!-- CMIREDIR:ocean_gyres: -->
203    \end{rawhtml}
204    
205  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
206  atmosphere. Ocean eddies play an important role in modifying the  atmosphere. Ocean eddies play an important role in modifying the
# Line 157  diffusive patterns of ocean currents. Bu Line 210  diffusive patterns of ocean currents. Bu
210  increased until the baroclinic instability process is resolved, numerical  increased until the baroclinic instability process is resolved, numerical
211  solutions of a different and much more realistic kind, can be obtained.  solutions of a different and much more realistic kind, can be obtained.
212    
213  Fig. ?.? shows the surface temperature and velocity field obtained from  Figure \ref{fig:ocean-gyres} shows the surface temperature and velocity
214  MITgcm run at $\frac{1}{6}^{\circ }$ horizontal resolution on a $lat-lon$  field obtained from MITgcm run at $\frac{1}{6}^{\circ }$ horizontal
215    resolution on a $lat-lon$
216  grid in which the pole has been rotated by 90$^{\circ }$ on to the equator  grid in which the pole has been rotated by 90$^{\circ }$ on to the equator
217  (to avoid the converging of meridian in northern latitudes). 21 vertical  (to avoid the converging of meridian in northern latitudes). 21 vertical
218  levels are used in the vertical with a `lopped cell' representation of  levels are used in the vertical with a `lopped cell' representation of
219  topography. The development and propagation of anomalously warm and cold  topography. The development and propagation of anomalously warm and cold
220  eddies can be clearly been seen in the Gulf Stream region. The transport of  eddies can be clearly seen in the Gulf Stream region. The transport of
221  warm water northward by the mean flow of the Gulf Stream is also clearly  warm water northward by the mean flow of the Gulf Stream is also clearly
222  visible.  visible.
223    
224  %% CNHbegin  %% CNHbegin
225  \input{part1/ocean_gyres_figure}  \input{part1/atl6_figure}
226  %% CNHend  %% CNHend
227    
228    
229  \subsection{Global ocean circulation}  \subsection{Global ocean circulation}
230    \begin{rawhtml}
231    <!-- CMIREDIR:global_ocean_circulation: -->
232    \end{rawhtml}
233    
234  Fig.E2a shows the pattern of ocean currents at the surface of a 4$^{\circ }$  Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean currents at
235    the surface of a 4$^{\circ }$
236  global ocean model run with 15 vertical levels. Lopped cells are used to  global ocean model run with 15 vertical levels. Lopped cells are used to
237  represent topography on a regular $lat-lon$ grid extending from 70$^{\circ  represent topography on a regular $lat-lon$ grid extending from 70$^{\circ
238  }N $ to 70$^{\circ }S$. The model is driven using monthly-mean winds with  }N $ to 70$^{\circ }S$. The model is driven using monthly-mean winds with
# Line 182  mixed boundary conditions on temperature Line 240  mixed boundary conditions on temperature
240  transfer properties of ocean eddies, convection and mixing is parameterized  transfer properties of ocean eddies, convection and mixing is parameterized
241  in this model.  in this model.
242    
243  Fig.E2b shows the meridional overturning circulation of the global ocean in  Figure \ref{fig:large-scale-circ} (bottom) shows the meridional overturning
244  Sverdrups.  circulation of the global ocean in Sverdrups.
245    
246  %%CNHbegin  %%CNHbegin
247  \input{part1/global_circ_figure}  \input{part1/global_circ_figure}
248  %%CNHend  %%CNHend
249    
250  \subsection{Convection and mixing over topography}  \subsection{Convection and mixing over topography}
251    \begin{rawhtml}
252    <!-- CMIREDIR:mixing_over_topography: -->
253    \end{rawhtml}
254    
255    
256  Dense plumes generated by localized cooling on the continental shelf of the  Dense plumes generated by localized cooling on the continental shelf of the
257  ocean may be influenced by rotation when the deformation radius is smaller  ocean may be influenced by rotation when the deformation radius is smaller
258  than the width of the cooling region. Rather than gravity plumes, the  than the width of the cooling region. Rather than gravity plumes, the
259  mechanism for moving dense fluid down the shelf is then through geostrophic  mechanism for moving dense fluid down the shelf is then through geostrophic
260  eddies. The simulation shown in the figure (blue is cold dense fluid, red is  eddies. The simulation shown in the figure \ref{fig:convect-and-topo}
261    (blue is cold dense fluid, red is
262  warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to  warmer, lighter fluid) employs the non-hydrostatic capability of MITgcm to
263  trigger convection by surface cooling. The cold, dense water falls down the  trigger convection by surface cooling. The cold, dense water falls down the
264  slope but is deflected along the slope by rotation. It is found that  slope but is deflected along the slope by rotation. It is found that
# Line 208  instability of the along-slope current. Line 271  instability of the along-slope current.
271  %%CNHend  %%CNHend
272    
273  \subsection{Boundary forced internal waves}  \subsection{Boundary forced internal waves}
274    \begin{rawhtml}
275    <!-- CMIREDIR:boundary_forced_internal_waves: -->
276    \end{rawhtml}
277    
278  The unique ability of MITgcm to treat non-hydrostatic dynamics in the  The unique ability of MITgcm to treat non-hydrostatic dynamics in the
279  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
280  dynamics and mixing in oceanic canyons and ridges driven by large amplitude  dynamics and mixing in oceanic canyons and ridges driven by large amplitude
281  barotropic tidal currents imposed through open boundary conditions.  barotropic tidal currents imposed through open boundary conditions.
282    
283  Fig. ?.? shows the influence of cross-slope topographic variations on  Fig. \ref{fig:boundary-forced-wave} shows the influence of cross-slope
284    topographic variations on
285  internal wave breaking - the cross-slope velocity is in color, the density  internal wave breaking - the cross-slope velocity is in color, the density
286  contoured. The internal waves are excited by application of open boundary  contoured. The internal waves are excited by application of open boundary
287  conditions on the left.\ They propagate to the sloping boundary (represented  conditions on the left. They propagate to the sloping boundary (represented
288  using MITgcm's finite volume spatial discretization) where they break under  using MITgcm's finite volume spatial discretization) where they break under
289  nonhydrostatic dynamics.  nonhydrostatic dynamics.
290    
# Line 226  nonhydrostatic dynamics. Line 293  nonhydrostatic dynamics.
293  %%CNHend  %%CNHend
294    
295  \subsection{Parameter sensitivity using the adjoint of MITgcm}  \subsection{Parameter sensitivity using the adjoint of MITgcm}
296    \begin{rawhtml}
297    <!-- CMIREDIR:parameter_sensitivity: -->
298    \end{rawhtml}
299    
300  Forward and tangent linear counterparts of MITgcm are supported using an  Forward and tangent linear counterparts of MITgcm are supported using an
301  `automatic adjoint compiler'. These can be used in parameter sensitivity and  `automatic adjoint compiler'. These can be used in parameter sensitivity and
302  data assimilation studies.  data assimilation studies.
303    
304  As one example of application of the MITgcm adjoint, Fig.E4 maps the  As one example of application of the MITgcm adjoint, Figure \ref{fig:hf-sensitivity}
305  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
306  of the overturning streamfunction shown in fig?.? at 40$^{\circ }$N and $  of the overturning stream-function shown in figure \ref{fig:large-scale-circ}
307  \mathcal{H}$ is the air-sea heat flux 100 years before. We see that $J$ is  at 60$^{\circ }$N and $
308    \mathcal{H}(\lambda,\varphi)$ is the mean, local air-sea heat flux over
309    a 100 year period. We see that $J$ is
310  sensitive to heat fluxes over the Labrador Sea, one of the important sources  sensitive to heat fluxes over the Labrador Sea, one of the important sources
311  of deep water for the thermohaline circulations. This calculation also  of deep water for the thermohaline circulations. This calculation also
312  yields sensitivities to all other model parameters.  yields sensitivities to all other model parameters.
# Line 244  yields sensitivities to all other model Line 316  yields sensitivities to all other model
316  %%CNHend  %%CNHend
317    
318  \subsection{Global state estimation of the ocean}  \subsection{Global state estimation of the ocean}
319    \begin{rawhtml}
320    <!-- CMIREDIR:global_state_estimation: -->
321    \end{rawhtml}
322    
323    
324  An important application of MITgcm is in state estimation of the global  An important application of MITgcm is in state estimation of the global
325  ocean circulation. An appropriately defined `cost function', which measures  ocean circulation. An appropriately defined `cost function', which measures
326  the departure of the model from observations (both remotely sensed and  the departure of the model from observations (both remotely sensed and
327  insitu) over an interval of time, is minimized by adjusting `control  in-situ) over an interval of time, is minimized by adjusting `control
328  parameters' such as air-sea fluxes, the wind field, the initial conditions  parameters' such as air-sea fluxes, the wind field, the initial conditions
329  etc. Figure ?.? shows an estimate of the time-mean surface elevation of the  etc. Figure \ref{fig:assimilated-globes} shows the large scale planetary
330  ocean obtained by bringing the model in to consistency with altimetric and  circulation and a Hopf-Muller plot of Equatorial sea-surface height.
331  in-situ observations over the period 1992-1997.  Both are obtained from assimilation bringing the model in to
332    consistency with altimetric and in-situ observations over the period
333    1992-1997.
334    
335  %% CNHbegin  %% CNHbegin
336  \input{part1/globes_figure}  \input{part1/assim_figure}
337  %% CNHend  %% CNHend
338    
339  \subsection{Ocean biogeochemical cycles}  \subsection{Ocean biogeochemical cycles}
340    \begin{rawhtml}
341    <!-- CMIREDIR:ocean_biogeo_cycles: -->
342    \end{rawhtml}
343    
344  MITgcm is being used to study global biogeochemical cycles in the ocean. For  MITgcm is being used to study global biogeochemical cycles in the ocean. For
345  example one can study the effects of interannual changes in meteorological  example one can study the effects of interannual changes in meteorological
346  forcing and upper ocean circulation on the fluxes of carbon dioxide and  forcing and upper ocean circulation on the fluxes of carbon dioxide and
347  oxygen between the ocean and atmosphere. The figure shows the annual air-sea  oxygen between the ocean and atmosphere. Figure \ref{fig:biogeo} shows
348  flux of oxygen and its relation to density outcrops in the southern oceans  the annual air-sea flux of oxygen and its relation to density outcrops in
349  from a single year of a global, interannually varying simulation.  the southern oceans from a single year of a global, interannually varying
350    simulation. The simulation is run at $1^{\circ}\times1^{\circ}$ resolution
351    telescoping to $\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not shown).
352    
353  %%CNHbegin  %%CNHbegin
354  \input{part1/biogeo_figure}  \input{part1/biogeo_figure}
355  %%CNHend  %%CNHend
356    
357  \subsection{Simulations of laboratory experiments}  \subsection{Simulations of laboratory experiments}
358    \begin{rawhtml}
359    <!-- CMIREDIR:classroom_exp: -->
360    \end{rawhtml}
361    
362  Figure ?.? shows MITgcm being used to simulate a laboratory experiment  Figure \ref{fig:lab-simulation} shows MITgcm being used to simulate a
363  enquiring in to the dynamics of the Antarctic Circumpolar Current (ACC). An  laboratory experiment inquiring into the dynamics of the Antarctic Circumpolar Current (ACC). An
364  initially homogeneous tank of water ($1m$ in diameter) is driven from its  initially homogeneous tank of water ($1m$ in diameter) is driven from its
365  free surface by a rotating heated disk. The combined action of mechanical  free surface by a rotating heated disk. The combined action of mechanical
366  and thermal forcing creates a lens of fluid which becomes baroclinically  and thermal forcing creates a lens of fluid which becomes baroclinically
367  unstable. The stratification and depth of penetration of the lens is  unstable. The stratification and depth of penetration of the lens is
368  arrested by its instability in a process analogous to that whic sets the  arrested by its instability in a process analogous to that which sets the
369  stratification of the ACC.  stratification of the ACC.
370    
371  %%CNHbegin  %%CNHbegin
# Line 290  stratification of the ACC. Line 376  stratification of the ACC.
376  % $Name$  % $Name$
377    
378  \section{Continuous equations in `r' coordinates}  \section{Continuous equations in `r' coordinates}
379    \begin{rawhtml}
380    <!-- CMIREDIR:z-p_isomorphism: -->
381    \end{rawhtml}
382    
383  To render atmosphere and ocean models from one dynamical core we exploit  To render atmosphere and ocean models from one dynamical core we exploit
384  `isomorphisms' between equation sets that govern the evolution of the  `isomorphisms' between equation sets that govern the evolution of the
385  respective fluids - see fig.4  respective fluids - see figure \ref{fig:isomorphic-equations}.
386  \marginpar{  One system of hydrodynamical equations is written down
 Fig.4. Isomorphisms}. One system of hydrodynamical equations is written down  
387  and encoded. The model variables have different interpretations depending on  and encoded. The model variables have different interpretations depending on
388  whether the atmosphere or ocean is being studied. Thus, for example, the  whether the atmosphere or ocean is being studied. Thus, for example, the
389  vertical coordinate `$r$' is interpreted as pressure, $p$, if we are  vertical coordinate `$r$' is interpreted as pressure, $p$, if we are
390  modeling the atmosphere and height, $z$, if we are modeling the ocean.  modeling the atmosphere (right hand side of figure \ref{fig:isomorphic-equations})
391    and height, $z$, if we are modeling the ocean (left hand side of figure
392    \ref{fig:isomorphic-equations}).
393    
394  %%CNHbegin  %%CNHbegin
395  \input{part1/zandpcoord_figure.tex}  \input{part1/zandpcoord_figure.tex}
# Line 311  velocity $\vec{\mathbf{v}}$, active trac Line 401  velocity $\vec{\mathbf{v}}$, active trac
401  depend on $\theta $, $S$, and $p$. The equations that govern the evolution  depend on $\theta $, $S$, and $p$. The equations that govern the evolution
402  of these fields, obtained by applying the laws of classical mechanics and  of these fields, obtained by applying the laws of classical mechanics and
403  thermodynamics to a Boussinesq, Navier-Stokes fluid are, written in terms of  thermodynamics to a Boussinesq, Navier-Stokes fluid are, written in terms of
404  a generic vertical coordinate, $r$, see fig.5  a generic vertical coordinate, $r$, so that the appropriate
405  \marginpar{  kinematic boundary conditions can be applied isomorphically
406  Fig.5 The vertical coordinate of model}:  see figure \ref{fig:zandp-vert-coord}.
407    
408  %%CNHbegin  %%CNHbegin
409  \input{part1/vertcoord_figure.tex}  \input{part1/vertcoord_figure.tex}
410  %%CNHend  %%CNHend
411    
412  \begin{equation*}  \begin{equation}
413  \frac{D\vec{\mathbf{v}_{h}}}{Dt}+\left( 2\vec{\Omega}\times \vec{\mathbf{v}}  \frac{D\vec{\mathbf{v}_{h}}}{Dt}+\left( 2\vec{\Omega}\times \vec{\mathbf{v}}
414  \right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}}  \right) _{h}+\mathbf{\nabla }_{h}\phi =\mathcal{F}_{\vec{\mathbf{v}_{h}}}
415  \text{ horizontal mtm}  \text{ horizontal mtm} \label{eq:horizontal_mtm}
416  \end{equation*}  \end{equation}
417    
418  \begin{equation*}  \begin{equation}
419  \frac{D\dot{r}}{Dt}+\widehat{k}\cdot \left( 2\vec{\Omega}\times \vec{\mathbf{  \frac{D\dot{r}}{Dt}+\widehat{k}\cdot \left( 2\vec{\Omega}\times \vec{\mathbf{
420  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{
421  vertical mtm}  vertical mtm} \label{eq:vertical_mtm}
422  \end{equation*}  \end{equation}
423    
424  \begin{equation}  \begin{equation}
425  \mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{  \mathbf{\nabla }_{h}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \dot{r}}{
426  \partial r}=0\text{ continuity}  \label{eq:continuous}  \partial r}=0\text{ continuity}  \label{eq:continuity}
427  \end{equation}  \end{equation}
428    
429  \begin{equation*}  \begin{equation}
430  b=b(\theta ,S,r)\text{ equation of state}  b=b(\theta ,S,r)\text{ equation of state} \label{eq:equation_of_state}
431  \end{equation*}  \end{equation}
432    
433  \begin{equation*}  \begin{equation}
434  \frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature}  \frac{D\theta }{Dt}=\mathcal{Q}_{\theta }\text{ potential temperature}
435  \end{equation*}  \label{eq:potential_temperature}
436    \end{equation}
437    
438  \begin{equation*}  \begin{equation}
439  \frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity}  \frac{DS}{Dt}=\mathcal{Q}_{S}\text{ humidity/salinity}
440  \end{equation*}  \label{eq:humidity_salt}
441    \end{equation}
442    
443  Here:  Here:
444    
# Line 410  S\text{ is specific humidity in the atmo Line 502  S\text{ is specific humidity in the atmo
502  \end{equation*}  \end{equation*}
503    
504  The $\mathcal{F}^{\prime }s$ and $\mathcal{Q}^{\prime }s$ are provided by  The $\mathcal{F}^{\prime }s$ and $\mathcal{Q}^{\prime }s$ are provided by
505  extensive `physics' packages for atmosphere and ocean described in Chapter 6.  `physics' and forcing packages for atmosphere and ocean. These are described
506    in later chapters.
507    
508  \subsection{Kinematic Boundary conditions}  \subsection{Kinematic Boundary conditions}
509    
510  \subsubsection{vertical}  \subsubsection{vertical}
511    
512  at fixed and moving $r$ surfaces we set (see fig.5):  at fixed and moving $r$ surfaces we set (see figure \ref{fig:zandp-vert-coord}):
513    
514  \begin{equation}  \begin{equation}
515  \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)}
516  \label{eq:fixedbc}  \label{eq:fixedbc}
517  \end{equation}  \end{equation}
518    
519  \begin{equation}  \begin{equation}
520  \dot{r}=\frac{Dr}{Dt}atr=R_{moving}\text{ \  \dot{r}=\frac{Dr}{Dt} \text{\ at\ } r=R_{moving}\text{ \
521  (oceansurface,bottomoftheatmosphere)}  \label{eq:movingbc}  (ocean surface,bottom of the atmosphere)}  \label{eq:movingbc}
522  \end{equation}  \end{equation}
523    
524  Here  Here
# Line 447  where $\vec{\mathbf{n}}$ is the normal t Line 540  where $\vec{\mathbf{n}}$ is the normal t
540    
541  \subsection{Atmosphere}  \subsection{Atmosphere}
542    
543  In the atmosphere, see fig.5, we interpret:  In the atmosphere, (see figure \ref{fig:zandp-vert-coord}), we interpret:
544    
545  \begin{equation}  \begin{equation}
546  r=p\text{ is the pressure}  \label{eq:atmos-r}  r=p\text{ is the pressure}  \label{eq:atmos-r}
# Line 518  The boundary conditions at top and botto Line 611  The boundary conditions at top and botto
611  atmosphere)}  \label{eq:moving-bc-atmos}  atmosphere)}  \label{eq:moving-bc-atmos}
612  \end{eqnarray}  \end{eqnarray}
613    
614  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})
615  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 $p$
616  coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}).  coordinates in Appendix Atmosphere - see eqs(\ref{eq:atmos-prime}).
617    
618  \subsection{Ocean}  \subsection{Ocean}
# Line 555  w &=&\frac{D\eta }{Dt}\text{ at }r=R_{mo Line 648  w &=&\frac{D\eta }{Dt}\text{ at }r=R_{mo
648  \end{eqnarray}  \end{eqnarray}
649  where $\eta $ is the elevation of the free surface.  where $\eta $ is the elevation of the free surface.
650    
651  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
652    of oceanic equations
653  which, for convenience, are written out in $z$ coordinates in Appendix Ocean  which, for convenience, are written out in $z$ coordinates in Appendix Ocean
654  - see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}).  - see eqs(\ref{eq:ocean-mom}) to (\ref{eq:ocean-salt}).
655    
656  \subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and  \subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and
657  Non-hydrostatic forms}  Non-hydrostatic forms}
658    \begin{rawhtml}
659    <!-- CMIREDIR:non_hydrostatic: -->
660    \end{rawhtml}
661    
662    
663  Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms:  Let us separate $\phi $ in to surface, hydrostatic and non-hydrostatic terms:
664    
# Line 568  Let us separate $\phi $ in to surface, h Line 666  Let us separate $\phi $ in to surface, h
666  \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)
667  \label{eq:phi-split}  \label{eq:phi-split}
668  \end{equation}  \end{equation}
669  and write eq(\ref{incompressible}a,b) in the form:  %and write eq(\ref{eq:incompressible}) in the form:
670    %                  ^- this eq is missing (jmc) ; replaced with:
671    and write eq( \ref{eq:horizontal_mtm}) in the form:
672    
673  \begin{equation}  \begin{equation}
674  \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 601  discussion: Line 701  discussion:
701  \left.  \left.
702  \begin{tabular}{l}  \begin{tabular}{l}
703  $G_{u}=-\vec{\mathbf{v}}.\nabla u$ \\  $G_{u}=-\vec{\mathbf{v}}.\nabla u$ \\
704  $-\left\{ \underline{\frac{u\dot{r}}{{r}}}-\frac{uv\tan lat}{{r}}\right\} $  $-\left\{ \underline{\frac{u\dot{r}}{{r}}}-\frac{uv\tan \varphi}{{r}}\right\} $
705  \\  \\
706  $-\left\{ -2\Omega v\sin lat+\underline{2\Omega \dot{r}\cos lat}\right\} $  $-\left\{ -2\Omega v\sin \varphi+\underline{2\Omega \dot{r}\cos \varphi}\right\} $
707  \\  \\
708  $+\mathcal{F}_{u}$  $+\mathcal{F}_{u}$
709  \end{tabular}  \end{tabular}
# Line 621  $+\mathcal{F}_{u}$ Line 721  $+\mathcal{F}_{u}$
721  \left.  \left.
722  \begin{tabular}{l}  \begin{tabular}{l}
723  $G_{v}=-\vec{\mathbf{v}}.\nabla v$ \\  $G_{v}=-\vec{\mathbf{v}}.\nabla v$ \\
724  $-\left\{ \underline{\frac{v\dot{r}}{{r}}}-\frac{u^{2}\tan lat}{{r}}\right\}  $-\left\{ \underline{\frac{v\dot{r}}{{r}}}-\frac{u^{2}\tan \varphi}{{r}}\right\}
725  $ \\  $ \\
726  $-\left\{ -2\Omega u\sin lat\right\} $ \\  $-\left\{ -2\Omega u\sin \varphi \right\} $ \\
727  $+\mathcal{F}_{v}$  $+\mathcal{F}_{v}$
728  \end{tabular}  \end{tabular}
729  \ \right\} \left\{  \ \right\} \left\{
# Line 642  $+\mathcal{F}_{v}$ Line 742  $+\mathcal{F}_{v}$
742  \begin{tabular}{l}  \begin{tabular}{l}
743  $G_{\dot{r}}=-\underline{\underline{\vec{\mathbf{v}}.\nabla \dot{r}}}$ \\  $G_{\dot{r}}=-\underline{\underline{\vec{\mathbf{v}}.\nabla \dot{r}}}$ \\
744  $+\left\{ \underline{\frac{u^{_{^{2}}}+v^{2}}{{r}}}\right\} $ \\  $+\left\{ \underline{\frac{u^{_{^{2}}}+v^{2}}{{r}}}\right\} $ \\
745  ${+}\underline{{2\Omega u\cos lat}}$ \\  ${+}\underline{{2\Omega u\cos \varphi}}$ \\
746  $\underline{\underline{\mathcal{F}_{\dot{r}}}}$  $\underline{\underline{\mathcal{F}_{\dot{r}}}}$
747  \end{tabular}  \end{tabular}
748  \ \right\} \left\{  \ \right\} \left\{
# Line 656  $\underline{\underline{\mathcal{F}_{\dot Line 756  $\underline{\underline{\mathcal{F}_{\dot
756  \end{equation}  \end{equation}
757  \qquad \qquad \qquad \qquad \qquad  \qquad \qquad \qquad \qquad \qquad
758    
759  In the above `${r}$' is the distance from the center of the earth and `$lat$  In the above `${r}$' is the distance from the center of the earth and `$\varphi$
760  ' is latitude.  ' is latitude.
761    
762  Grad and div operators in spherical coordinates are defined in appendix  Grad and div operators in spherical coordinates are defined in appendix
763  OPERATORS.  OPERATORS.
 \marginpar{  
 Fig.6 Spherical polar coordinate system.}  
764    
765  %%CNHbegin  %%CNHbegin
766  \input{part1/sphere_coord_figure.tex}  \input{part1/sphere_coord_figure.tex}
# Line 681  r $ in, for example, (\ref{eq:gu-speheri Line 779  r $ in, for example, (\ref{eq:gu-speheri
779  the radius of the earth.  the radius of the earth.
780    
781  \subsubsection{Hydrostatic and quasi-hydrostatic forms}  \subsubsection{Hydrostatic and quasi-hydrostatic forms}
782    \label{sec:hydrostatic_and_quasi-hydrostatic_forms}
783    
784  These are discussed at length in Marshall et al (1997a).  These are discussed at length in Marshall et al (1997a).
785    
# Line 694  computed at all other levels by integrat Line 793  computed at all other levels by integrat
793    
794  In the `quasi-hydrostatic' equations (\textbf{QH)} strict balance between  In the `quasi-hydrostatic' equations (\textbf{QH)} strict balance between
795  gravity and vertical pressure gradients is not imposed. The $2\Omega u\cos  gravity and vertical pressure gradients is not imposed. The $2\Omega u\cos
796  \phi $ Coriolis term are not neglected and are balanced by a non-hydrostatic  \varphi $ Coriolis term are not neglected and are balanced by a non-hydrostatic
797  contribution to the pressure field: only the terms underlined twice in Eqs. (  contribution to the pressure field: only the terms underlined twice in Eqs. (
798  \ref{eq:gu-speherical}$\rightarrow $\ \ref{eq:gw-spherical}) are set to zero  \ref{eq:gu-speherical}$\rightarrow $\ \ref{eq:gw-spherical}) are set to zero
799  and, simultaneously, the shallow atmosphere approximation is relaxed. In  and, simultaneously, the shallow atmosphere approximation is relaxed. In
# Line 703  variation of the radial position of a pa Line 802  variation of the radial position of a pa
802  vertical momentum equation (\ref{eq:mom-w}) becomes:  vertical momentum equation (\ref{eq:mom-w}) becomes:
803    
804  \begin{equation*}  \begin{equation*}
805  \frac{\partial \phi _{nh}}{\partial r}=2\Omega u\cos lat  \frac{\partial \phi _{nh}}{\partial r}=2\Omega u\cos \varphi
806  \end{equation*}  \end{equation*}
807  making a small correction to the hydrostatic pressure.  making a small correction to the hydrostatic pressure.
808    
# Line 724  In the non-hydrostatic ocean model all t Line 823  In the non-hydrostatic ocean model all t
823  three dimensional elliptic equation must be solved subject to Neumann  three dimensional elliptic equation must be solved subject to Neumann
824  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
825  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
826  incompressible condition eq(\ref{eq:continuous})c has already filtered out  incompressible condition eq(\ref{eq:continuity}) has already filtered out
827  acoustic modes. It does, however, ensure that the gravity waves are treated  acoustic modes. It does, however, ensure that the gravity waves are treated
828  accurately with an exact dispersion relation. The \textbf{NH} set has a  accurately with an exact dispersion relation. The \textbf{NH} set has a
829  complete angular momentum principle and consistent energetics - see White  complete angular momentum principle and consistent energetics - see White
# Line 773  coordinates are supported - see eqs(\ref Line 872  coordinates are supported - see eqs(\ref
872  \subsection{Solution strategy}  \subsection{Solution strategy}
873    
874  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{
875  NH} models is summarized in Fig.7.  NH} models is summarized in Figure \ref{fig:solution-strategy}.
876  \marginpar{  Under all dynamics, a 2-d elliptic equation is
 Fig.7 Solution strategy} Under all dynamics, a 2-d elliptic equation is  
877  first solved to find the surface pressure and the hydrostatic pressure at  first solved to find the surface pressure and the hydrostatic pressure at
878  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
879  \textbf{QH} dynamics, the horizontal momentum equations are then stepped  \textbf{QH} dynamics, the horizontal momentum equations are then stepped
# Line 789  stepping forward the vertical momentum e Line 887  stepping forward the vertical momentum e
887  %%CNHend  %%CNHend
888    
889  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
890  course, some complication that goes with the inclusion of $\cos \phi \ $  course, some complication that goes with the inclusion of $\cos \varphi \ $
891  Coriolis terms and the relaxation of the shallow atmosphere approximation.  Coriolis terms and the relaxation of the shallow atmosphere approximation.
892  But this leads to negligible increase in computation. In \textbf{NH}, in  But this leads to negligible increase in computation. In \textbf{NH}, in
893  contrast, one additional elliptic equation - a three-dimensional one - must  contrast, one additional elliptic equation - a three-dimensional one - must
# Line 799  Marshall et al, 1997) resulting in a non Line 897  Marshall et al, 1997) resulting in a non
897  hydrostatic limit, is as computationally economic as the \textbf{HPEs}.  hydrostatic limit, is as computationally economic as the \textbf{HPEs}.
898    
899  \subsection{Finding the pressure field}  \subsection{Finding the pressure field}
900    \label{sec:finding_the_pressure_field}
901    
902  Unlike the prognostic variables $u$, $v$, $w$, $\theta $ and $S$, the  Unlike the prognostic variables $u$, $v$, $w$, $\theta $ and $S$, the
903  pressure field must be obtained diagnostically. We proceed, as before, by  pressure field must be obtained diagnostically. We proceed, as before, by
# Line 831  atmospheric pressure pushing down on the Line 930  atmospheric pressure pushing down on the
930    
931  \subsubsection{Surface pressure}  \subsubsection{Surface pressure}
932    
933  The surface pressure equation can be obtained by integrating continuity, (  The surface pressure equation can be obtained by integrating continuity,
934  \ref{eq:continuous})c, vertically from $r=R_{fixed}$ to $r=R_{moving}$  (\ref{eq:continuity}), vertically from $r=R_{fixed}$ to $r=R_{moving}$
935    
936  \begin{equation*}  \begin{equation*}
937  \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}
# Line 857  r $. The above can be rearranged to yiel Line 956  r $. The above can be rearranged to yiel
956  where we have incorporated a source term.  where we have incorporated a source term.
957    
958  Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential  Whether $\phi $ is pressure (ocean model, $p/\rho _{c}$) or geopotential
959  (atmospheric model), in (\ref{mtm-split}), the horizontal gradient term can  (atmospheric model), in (\ref{eq:mom-h}), the horizontal gradient term can
960  be written  be written
961  \begin{equation}  \begin{equation}
962  \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)
# Line 865  be written Line 964  be written
964  \end{equation}  \end{equation}
965  where $b_{s}$ is the buoyancy at the surface.  where $b_{s}$ is the buoyancy at the surface.
966    
967  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
968  {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
969  elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free  elliptic equation for $\phi _{s}$ as described in Chapter 2. Both `free
970  surface' and `rigid lid' approaches are available.  surface' and `rigid lid' approaches are available.
971    
972  \subsubsection{Non-hydrostatic pressure}  \subsubsection{Non-hydrostatic pressure}
973    
974  Taking the horizontal divergence of (\ref{hor-mtm}) and adding $\frac{  Taking the horizontal divergence of (\ref{eq:mom-h}) and adding
975  \partial }{\partial r}$ of (\ref{vertmtm}), invoking the continuity equation  $\frac{\partial }{\partial r}$ of (\ref{eq:mom-w}), invoking the continuity equation
976  (\ref{incompressible}), we deduce that:  (\ref{eq:continuity}), we deduce that:
977    
978  \begin{equation}  \begin{equation}
979  \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{
# Line 904  tangential component of velocity, $v_{T} Line 1003  tangential component of velocity, $v_{T}
1003  depending on the form chosen for the dissipative terms in the momentum  depending on the form chosen for the dissipative terms in the momentum
1004  equations - see below.  equations - see below.
1005    
1006  Eq.(\ref{nonormalflow}) implies, making use of (\ref{mtm-split}), that:  Eq.(\ref{nonormalflow}) implies, making use of (\ref{eq:mom-h}), that:
1007    
1008  \begin{equation}  \begin{equation}
1009  \widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}}  \widehat{n}.\nabla \phi _{nh}=\widehat{n}.\vec{\mathbf{F}}
# Line 944  If the flow is `close' to hydrostatic ba Line 1043  If the flow is `close' to hydrostatic ba
1043  converges rapidly because $\phi _{nh}\ $is then only a small correction to  converges rapidly because $\phi _{nh}\ $is then only a small correction to
1044  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).
1045    
1046  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})
1047  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.
1048    
1049  \subsection{Forcing/dissipation}  \subsection{Forcing/dissipation}
# Line 952  does not vanish at $r=R_{moving}$, and s Line 1051  does not vanish at $r=R_{moving}$, and s
1051  \subsubsection{Forcing}  \subsubsection{Forcing}
1052    
1053  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
1054  `physics packages' described in detail in chapter ??.  `physics packages' and forcing packages. These are described later on.
1055    
1056  \subsubsection{Dissipation}  \subsubsection{Dissipation}
1057    
# Line 1000  salinity ... ). Line 1099  salinity ... ).
1099  \subsection{Vector invariant form}  \subsection{Vector invariant form}
1100    
1101  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
1102  {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:
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 1018  to discretize the model. Line 1117  to discretize the model.
1117    
1118  \subsection{Adjoint}  \subsection{Adjoint}
1119    
1120  Tangent linear and adjoint counterparts of the forward model and described  Tangent linear and adjoint counterparts of the forward model are described
1121  in Chapter 5.  in Chapter 5.
1122    
1123  % $Header$  % $Header$
# Line 1045  c_{v}\frac{DT}{Dt}+p\frac{D\alpha }{Dt} Line 1144  c_{v}\frac{DT}{Dt}+p\frac{D\alpha }{Dt}
1144  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
1145  surfaces) component of velocity,$\frac{D}{Dt}=\vec{\mathbf{v}}_{h}\cdot  surfaces) component of velocity,$\frac{D}{Dt}=\vec{\mathbf{v}}_{h}\cdot
1146  \mathbf{\nabla }_{p}+\omega \frac{\partial }{\partial p}$ is the total  \mathbf{\nabla }_{p}+\omega \frac{\partial }{\partial p}$ is the total
1147  derivative, $f=2\Omega \sin lat$ is the Coriolis parameter, $\phi =gz$ is  derivative, $f=2\Omega \sin \varphi$ is the Coriolis parameter, $\phi =gz$ is
1148  the geopotential, $\alpha =1/\rho $ is the specific volume, $\omega =\frac{Dp  the geopotential, $\alpha =1/\rho $ is the specific volume, $\omega =\frac{Dp
1149  }{Dt}$ is the vertical velocity in the $p-$coordinate. Equation(\ref  }{Dt}$ is the vertical velocity in the $p-$coordinate. Equation(\ref
1150  {eq:atmos-heat}) is the first law of thermodynamics where internal energy $  {eq:atmos-heat}) is the first law of thermodynamics where internal energy $
# Line 1140  _{o}(p_{o})=g~Z_{topo}$, defined: Line 1239  _{o}(p_{o})=g~Z_{topo}$, defined:
1239  The final form of the HPE's in p coordinates is then:  The final form of the HPE's in p coordinates is then:
1240  \begin{eqnarray}  \begin{eqnarray}
1241  \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}}
1242  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \\  _{h}+\mathbf{\nabla }_{p}\phi ^{\prime } &=&\vec{\mathbf{\mathcal{F}}} \label{eq:atmos-prime} \\
1243  \frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\  \frac{\partial \phi ^{\prime }}{\partial p}+\alpha ^{\prime } &=&0 \\
1244  \mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{  \mathbf{\nabla }_{p}\cdot \vec{\mathbf{v}}_{h}+\frac{\partial \omega }{
1245  \partial p} &=&0 \\  \partial p} &=&0 \\
1246  \frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\  \frac{\partial \Pi }{\partial p}\theta ^{\prime } &=&\alpha ^{\prime } \\
1247  \frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi }  \label{eq:atmos-prime}  \frac{D\theta }{Dt} &=&\frac{\mathcal{Q}}{\Pi }
1248  \end{eqnarray}  \end{eqnarray}
1249    
1250  % $Header$  % $Header$
# Line 1164  _{h}+\frac{1}{\rho }\mathbf{\nabla }_{z} Line 1263  _{h}+\frac{1}{\rho }\mathbf{\nabla }_{z}
1263  \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}
1264  &=&\epsilon _{nh}\mathcal{F}_{w} \\  &=&\epsilon _{nh}\mathcal{F}_{w} \\
1265  \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}}
1266  _{h}+\frac{\partial w}{\partial z} &=&0 \\  _{h}+\frac{\partial w}{\partial z} &=&0 \label{eq-zns-cont}\\
1267  \rho &=&\rho (\theta ,S,p) \\  \rho &=&\rho (\theta ,S,p) \label{eq-zns-eos}\\
1268  \frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \\  \frac{D\theta }{Dt} &=&\mathcal{Q}_{\theta } \label{eq-zns-heat}\\
1269  \frac{DS}{Dt} &=&\mathcal{Q}_{s}  \label{eq:non-boussinesq}  \frac{DS}{Dt} &=&\mathcal{Q}_{s}  \label{eq-zns-salt}
1270    \label{eq:non-boussinesq}
1271  \end{eqnarray}  \end{eqnarray}
1272  These equations permit acoustics modes, inertia-gravity waves,  These equations permit acoustics modes, inertia-gravity waves,
1273  non-hydrostatic motions, a geostrophic (Rossby) mode and a thermo-haline  non-hydrostatic motions, a geostrophic (Rossby) mode and a thermohaline
1274  mode. As written, they cannot be integrated forward consistently - if we  mode. As written, they cannot be integrated forward consistently - if we
1275  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
1276  consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref  consistent with that obtained by stepping (\ref{eq-zns-heat}) and (\ref
# Line 1186  _{\theta ,S}\frac{Dp}{Dt}  \label{EOSexp Line 1286  _{\theta ,S}\frac{Dp}{Dt}  \label{EOSexp
1286  \end{equation}  \end{equation}
1287    
1288  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
1289  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:  
1290  \begin{equation}  \begin{equation}
1291  \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{
1292  v}}+\partial _{z}w\approx 0  \label{eq-zns-pressure}  v}}+\partial _{z}w\approx 0  \label{eq-zns-pressure}
# Line 1377  In spherical coordinates, the velocity c Line 1476  In spherical coordinates, the velocity c
1476  and vertical direction respectively, are given by (see Fig.2) :  and vertical direction respectively, are given by (see Fig.2) :
1477    
1478  \begin{equation*}  \begin{equation*}
1479  u=r\cos \phi \frac{D\lambda }{Dt}  u=r\cos \varphi \frac{D\lambda }{Dt}
1480  \end{equation*}  \end{equation*}
1481    
1482  \begin{equation*}  \begin{equation*}
1483  v=r\frac{D\phi }{Dt}\qquad  v=r\frac{D\varphi }{Dt}\qquad
1484  \end{equation*}  \end{equation*}
1485  $\qquad \qquad \qquad \qquad $  $\qquad \qquad \qquad \qquad $
1486    
# Line 1389  $\qquad \qquad \qquad \qquad $ Line 1488  $\qquad \qquad \qquad \qquad $
1488  \dot{r}=\frac{Dr}{Dt}  \dot{r}=\frac{Dr}{Dt}
1489  \end{equation*}  \end{equation*}
1490    
1491  Here $\phi $ is the latitude, $\lambda $ the longitude, $r$ the radial  Here $\varphi $ is the latitude, $\lambda $ the longitude, $r$ the radial
1492  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
1493  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.
1494    
# Line 1397  The `grad' ($\nabla $) and `div' ($\nabl Line 1496  The `grad' ($\nabla $) and `div' ($\nabl
1496  spherical coordinates:  spherical coordinates:
1497    
1498  \begin{equation*}  \begin{equation*}
1499  \nabla \equiv \left( \frac{1}{r\cos \phi }\frac{\partial }{\partial \lambda }  \nabla \equiv \left( \frac{1}{r\cos \varphi }\frac{\partial }{\partial \lambda }
1500  ,\frac{1}{r}\frac{\partial }{\partial \phi },\frac{\partial }{\partial r}  ,\frac{1}{r}\frac{\partial }{\partial \varphi },\frac{\partial }{\partial r}
1501  \right)  \right)
1502  \end{equation*}  \end{equation*}
1503    
1504  \begin{equation*}  \begin{equation*}
1505  \nabla .v\equiv \frac{1}{r\cos \phi }\left\{ \frac{\partial u}{\partial  \nabla .v\equiv \frac{1}{r\cos \varphi }\left\{ \frac{\partial u}{\partial
1506  \lambda }+\frac{\partial }{\partial \phi }\left( v\cos \phi \right) \right\}  \lambda }+\frac{\partial }{\partial \varphi }\left( v\cos \varphi \right) \right\}
1507  +\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}
1508  \end{equation*}  \end{equation*}
1509    

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