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revision 1.21 by edhill, Sat Oct 16 03:40:12 2004 UTC revision 1.29 by jmc, Mon Aug 30 23:09:21 2010 UTC
# Line 61  hydrodynamical kernel is used to drive f Line 61  hydrodynamical kernel is used to drive f
61  models - see fig \ref{fig:onemodel}  models - see fig \ref{fig:onemodel}
62    
63  %% CNHbegin  %% CNHbegin
64  \input{part1/one_model_figure}  \input{s_overview/text/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 \ref{fig:all-scales}  small-scale and large scale processes - see fig \ref{fig:all-scales}
69    
70  %% CNHbegin  %% CNHbegin
71  \input{part1/all_scales_figure}  \input{s_overview/text/all_scales_figure}
72  %% CNHend  %% CNHend
73    
74  \item finite volume techniques are employed yielding an intuitive  \item finite volume techniques are employed yielding an intuitive
# Line 76  discretization and support for the treat Line 76  discretization and support for the treat
76  orthogonal curvilinear grids and shaved cells - see fig \ref{fig:finite-volumes}  orthogonal curvilinear grids and shaved cells - see fig \ref{fig:finite-volumes}
77    
78  %% CNHbegin  %% CNHbegin
79  \input{part1/fvol_figure}  \input{s_overview/text/fvol_figure}
80  %% CNHend  %% CNHend
81    
82  \item tangent linear and adjoint counterparts are automatically maintained  \item tangent linear and adjoint counterparts are automatically maintained
# Line 87  studies. Line 87  studies.
87  computational platforms.  computational platforms.
88  \end{itemize}  \end{itemize}
89    
90    
91  Key publications reporting on and charting the development of the model are  Key publications reporting on and charting the development of the model are
92  \cite{hill:95,marshall:97a,marshall:97b,adcroft:97,marshall:98,adcroft:99,hill:99,maro-eta:99}:  \cite{hill:95,marshall:97a,marshall:97b,adcroft:97,mars-eta:98,adcroft:99,hill:99,maro-eta:99,adcroft:04a,adcroft:04b,marshall:04}
93    (an overview on the model formulation can also be found in \cite{adcroft:04c}):
94    
95  \begin{verbatim}  \begin{verbatim}
96  Hill, C. and J. Marshall, (1995)  Hill, C. and J. Marshall, (1995)
# Line 142  give a feel for the wide range of proble Line 144  give a feel for the wide range of proble
144    
145  \section{Illustrations of the model in action}  \section{Illustrations of the model in action}
146    
147  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,
148  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
149  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
150  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 165  both atmospheric and oceanographic flows Line 167  both atmospheric and oceanographic flows
167    
168  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$mb$
169  temperature field obtained using the atmospheric isomorph of MITgcm run at  temperature field obtained using the atmospheric isomorph of MITgcm run at
170  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
171  (blue) and warm air along an equatorial band (red). Fully developed  (blue) and warm air along an equatorial band (red). Fully developed
172  baroclinic eddies spawned in the northern hemisphere storm track are  baroclinic eddies spawned in the northern hemisphere storm track are
173  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 175  in Held and Suarez; 1994 designed to tes Line 177  in Held and Suarez; 1994 designed to tes
177  there are no mountains or land-sea contrast.  there are no mountains or land-sea contrast.
178    
179  %% CNHbegin  %% CNHbegin
180  \input{part1/cubic_eddies_figure}  \input{s_overview/text/cubic_eddies_figure}
181  %% CNHend  %% CNHend
182    
183  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 191  cube-sphere grid and the flow calculated Line 193  cube-sphere grid and the flow calculated
193  latitude-longitude grid. Both grids are supported within the model.  latitude-longitude grid. Both grids are supported within the model.
194    
195  %% CNHbegin  %% CNHbegin
196  \input{part1/hs_zave_u_figure}  \input{s_overview/text/hs_zave_u_figure}
197  %% CNHend  %% CNHend
198    
199  \subsection{Ocean gyres}  \subsection{Ocean gyres}
# Line 210  diffusive patterns of ocean currents. Bu Line 212  diffusive patterns of ocean currents. Bu
212  increased until the baroclinic instability process is resolved, numerical  increased until the baroclinic instability process is resolved, numerical
213  solutions of a different and much more realistic kind, can be obtained.  solutions of a different and much more realistic kind, can be obtained.
214    
215  Figure \ref{fig:ocean-gyres} shows the surface temperature and velocity  Figure \ref{fig:ocean-gyres} shows the surface temperature and
216  field obtained from MITgcm run at $\frac{1}{6}^{\circ }$ horizontal  velocity field obtained from MITgcm run at $\frac{1}{6}^{\circ }$
217  resolution on a $lat-lon$  horizontal resolution on a \textit{lat-lon} grid in which the pole has
218  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
219  (to avoid the converging of meridian in northern latitudes). 21 vertical  converging of meridian in northern latitudes). 21 vertical levels are
220  levels are used in the vertical with a `lopped cell' representation of  used in the vertical with a `lopped cell' representation of
221  topography. The development and propagation of anomalously warm and cold  topography. The development and propagation of anomalously warm and
222  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
223  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
224  visible.  is also clearly visible.
225    
226  %% CNHbegin  %% CNHbegin
227  \input{part1/atl6_figure}  \input{s_overview/text/atl6_figure}
228  %% CNHend  %% CNHend
229    
230    
# Line 231  visible. Line 233  visible.
233  <!-- CMIREDIR:global_ocean_circulation: -->  <!-- CMIREDIR:global_ocean_circulation: -->
234  \end{rawhtml}  \end{rawhtml}
235    
236  Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean currents at  Figure \ref{fig:large-scale-circ} (top) shows the pattern of ocean
237  the surface of a 4$^{\circ }$  currents at the surface of a $4^{\circ }$ global ocean model run with
238  global ocean model run with 15 vertical levels. Lopped cells are used to  15 vertical levels. Lopped cells are used to represent topography on a
239  represent topography on a regular $lat-lon$ grid extending from 70$^{\circ  regular \textit{lat-lon} grid extending from $70^{\circ }N$ to
240  }N $ to 70$^{\circ }S$. The model is driven using monthly-mean winds with  $70^{\circ }S$. The model is driven using monthly-mean winds with
241  mixed boundary conditions on temperature and salinity at the surface. The  mixed boundary conditions on temperature and salinity at the surface.
242  transfer properties of ocean eddies, convection and mixing is parameterized  The transfer properties of ocean eddies, convection and mixing is
243  in this model.  parameterized in this model.
244    
245  Figure \ref{fig:large-scale-circ} (bottom) shows the meridional overturning  Figure \ref{fig:large-scale-circ} (bottom) shows the meridional overturning
246  circulation of the global ocean in Sverdrups.  circulation of the global ocean in Sverdrups.
247    
248  %%CNHbegin  %%CNHbegin
249  \input{part1/global_circ_figure}  \input{s_overview/text/global_circ_figure}
250  %%CNHend  %%CNHend
251    
252  \subsection{Convection and mixing over topography}  \subsection{Convection and mixing over topography}
# Line 267  strong, and replaced by lateral entrainm Line 269  strong, and replaced by lateral entrainm
269  instability of the along-slope current.  instability of the along-slope current.
270    
271  %%CNHbegin  %%CNHbegin
272  \input{part1/convect_and_topo}  \input{s_overview/text/convect_and_topo}
273  %%CNHend  %%CNHend
274    
275  \subsection{Boundary forced internal waves}  \subsection{Boundary forced internal waves}
# Line 289  using MITgcm's finite volume spatial dis Line 291  using MITgcm's finite volume spatial dis
291  nonhydrostatic dynamics.  nonhydrostatic dynamics.
292    
293  %%CNHbegin  %%CNHbegin
294  \input{part1/boundary_forced_waves}  \input{s_overview/text/boundary_forced_waves}
295  %%CNHend  %%CNHend
296    
297  \subsection{Parameter sensitivity using the adjoint of MITgcm}  \subsection{Parameter sensitivity using the adjoint of MITgcm}
# Line 301  Forward and tangent linear counterparts Line 303  Forward and tangent linear counterparts
303  `automatic adjoint compiler'. These can be used in parameter sensitivity and  `automatic adjoint compiler'. These can be used in parameter sensitivity and
304  data assimilation studies.  data assimilation studies.
305    
306  As one example of application of the MITgcm adjoint, Figure \ref{fig:hf-sensitivity}  As one example of application of the MITgcm adjoint, Figure
307  maps the gradient $\frac{\partial J}{\partial \mathcal{H}}$where $J$ is the magnitude  \ref{fig:hf-sensitivity} maps the gradient $\frac{\partial J}{\partial
308  of the overturning stream-function shown in figure \ref{fig:large-scale-circ}    \mathcal{H}}$where $J$ is the magnitude of the overturning
309  at 60$^{\circ }$N and $  stream-function shown in figure \ref{fig:large-scale-circ} at
310  \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
311  a 100 year period. We see that $J$ is  air-sea heat flux over a 100 year period. We see that $J$ is sensitive
312  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
313  of deep water for the thermohaline circulations. This calculation also  deep water for the thermohaline circulations. This calculation also
314  yields sensitivities to all other model parameters.  yields sensitivities to all other model parameters.
315    
316  %%CNHbegin  %%CNHbegin
317  \input{part1/adj_hf_ocean_figure}  \input{s_overview/text/adj_hf_ocean_figure}
318  %%CNHend  %%CNHend
319    
320  \subsection{Global state estimation of the ocean}  \subsection{Global state estimation of the ocean}
# Line 333  consistency with altimetric and in-situ Line 335  consistency with altimetric and in-situ
335  1992-1997.  1992-1997.
336    
337  %% CNHbegin  %% CNHbegin
338  \input{part1/assim_figure}  \input{s_overview/text/assim_figure}
339  %% CNHend  %% CNHend
340    
341  \subsection{Ocean biogeochemical cycles}  \subsection{Ocean biogeochemical cycles}
# Line 341  consistency with altimetric and in-situ Line 343  consistency with altimetric and in-situ
343  <!-- CMIREDIR:ocean_biogeo_cycles: -->  <!-- CMIREDIR:ocean_biogeo_cycles: -->
344  \end{rawhtml}  \end{rawhtml}
345    
346  MITgcm is being used to study global biogeochemical cycles in the ocean. For  MITgcm is being used to study global biogeochemical cycles in the
347  example one can study the effects of interannual changes in meteorological  ocean. For example one can study the effects of interannual changes in
348  forcing and upper ocean circulation on the fluxes of carbon dioxide and  meteorological forcing and upper ocean circulation on the fluxes of
349  oxygen between the ocean and atmosphere. Figure \ref{fig:biogeo} shows  carbon dioxide and oxygen between the ocean and atmosphere. Figure
350  the annual air-sea flux of oxygen and its relation to density outcrops in  \ref{fig:biogeo} shows the annual air-sea flux of oxygen and its
351  the southern oceans from a single year of a global, interannually varying  relation to density outcrops in the southern oceans from a single year
352  simulation. The simulation is run at $1^{\circ}\times1^{\circ}$ resolution  of a global, interannually varying simulation. The simulation is run
353  telescoping to $\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not shown).  at $1^{\circ}\times1^{\circ}$ resolution telescoping to
354    $\frac{1}{3}^{\circ}\times\frac{1}{3}^{\circ}$ in the tropics (not
355    shown).
356    
357  %%CNHbegin  %%CNHbegin
358  \input{part1/biogeo_figure}  \input{s_overview/text/biogeo_figure}
359  %%CNHend  %%CNHend
360    
361  \subsection{Simulations of laboratory experiments}  \subsection{Simulations of laboratory experiments}
# Line 369  arrested by its instability in a process Line 373  arrested by its instability in a process
373  stratification of the ACC.  stratification of the ACC.
374    
375  %%CNHbegin  %%CNHbegin
376  \input{part1/lab_figure}  \input{s_overview/text/lab_figure}
377  %%CNHend  %%CNHend
378    
379  % $Header$  % $Header$
# Line 392  and height, $z$, if we are modeling the Line 396  and height, $z$, if we are modeling the
396  \ref{fig:isomorphic-equations}).  \ref{fig:isomorphic-equations}).
397    
398  %%CNHbegin  %%CNHbegin
399  \input{part1/zandpcoord_figure.tex}  \input{s_overview/text/zandpcoord_figure.tex}
400  %%CNHend  %%CNHend
401    
402  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 406  kinematic boundary conditions can be app Line 410  kinematic boundary conditions can be app
410  see figure \ref{fig:zandp-vert-coord}.  see figure \ref{fig:zandp-vert-coord}.
411    
412  %%CNHbegin  %%CNHbegin
413  \input{part1/vertcoord_figure.tex}  \input{s_overview/text/vertcoord_figure.tex}
414  %%CNHend  %%CNHend
415    
416  \begin{equation}  \begin{equation}
# Line 657  which, for convenience, are written out Line 661  which, for convenience, are written out
661    
662  \subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and  \subsection{Hydrostatic, Quasi-hydrostatic, Quasi-nonhydrostatic and
663  Non-hydrostatic forms}  Non-hydrostatic forms}
664    \label{sec:all_hydrostatic_forms}
665  \begin{rawhtml}  \begin{rawhtml}
666  <!-- CMIREDIR:non_hydrostatic: -->  <!-- CMIREDIR:non_hydrostatic: -->
667  \end{rawhtml}  \end{rawhtml}
# Line 765  Grad and div operators in spherical coor Line 770  Grad and div operators in spherical coor
770  OPERATORS.  OPERATORS.
771    
772  %%CNHbegin  %%CNHbegin
773  \input{part1/sphere_coord_figure.tex}  \input{s_overview/text/sphere_coord_figure.tex}
774  %%CNHend  %%CNHend
775    
776  \subsubsection{Shallow atmosphere approximation}  \subsubsection{Shallow atmosphere approximation}
777    
778  Most models are based on the `hydrostatic primitive equations' (HPE's) in  Most models are based on the `hydrostatic primitive equations' (HPE's)
779  which the vertical momentum equation is reduced to a statement of  in which the vertical momentum equation is reduced to a statement of
780  hydrostatic balance and the `traditional approximation' is made in which the  hydrostatic balance and the `traditional approximation' is made in
781  Coriolis force is treated approximately and the shallow atmosphere  which the Coriolis force is treated approximately and the shallow
782  approximation is made.\ The MITgcm need not make the `traditional  atmosphere approximation is made.  MITgcm need not make the
783  approximation'. To be able to support consistent non-hydrostatic forms the  `traditional approximation'. To be able to support consistent
784  shallow atmosphere approximation can be relaxed - when dividing through by $  non-hydrostatic forms the shallow atmosphere approximation can be
785  r $ in, for example, (\ref{eq:gu-speherical}), we do not replace $r$ by $a$,  relaxed - when dividing through by $ r $ in, for example,
786  the radius of the earth.  (\ref{eq:gu-speherical}), we do not replace $r$ by $a$, the radius of
787    the earth.
788    
789  \subsubsection{Hydrostatic and quasi-hydrostatic forms}  \subsubsection{Hydrostatic and quasi-hydrostatic forms}
790  \label{sec:hydrostatic_and_quasi-hydrostatic_forms}  \label{sec:hydrostatic_and_quasi-hydrostatic_forms}
# Line 815  et.al., 1997a. As in \textbf{HPE }only a Line 821  et.al., 1997a. As in \textbf{HPE }only a
821    
822  \subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms}  \subsubsection{Non-hydrostatic and quasi-nonhydrostatic forms}
823    
824  The MIT model presently supports a full non-hydrostatic ocean isomorph, but  MITgcm presently supports a full non-hydrostatic ocean isomorph, but
825  only a quasi-non-hydrostatic atmospheric isomorph.  only a quasi-non-hydrostatic atmospheric isomorph.
826    
827  \paragraph{Non-hydrostatic Ocean}  \paragraph{Non-hydrostatic Ocean}
# Line 885  stepping forward the horizontal momentum Line 891  stepping forward the horizontal momentum
891  stepping forward the vertical momentum equation.  stepping forward the vertical momentum equation.
892    
893  %%CNHbegin  %%CNHbegin
894  \input{part1/solution_strategy_figure.tex}  \input{s_overview/text/solution_strategy_figure.tex}
895  %%CNHend  %%CNHend
896    
897  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 1074  friction. These coefficients are the sam Line 1080  friction. These coefficients are the sam
1080    
1081  The mixing terms for the temperature and salinity equations have a similar  The mixing terms for the temperature and salinity equations have a similar
1082  form to that of momentum except that the diffusion tensor can be  form to that of momentum except that the diffusion tensor can be
1083  non-diagonal and have varying coefficients. $\qquad $  non-diagonal and have varying coefficients.
1084  \begin{equation}  \begin{equation}
1085  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
1086  _{h}^{4}(T,S)  \label{eq:diffusion}  _{h}^{4}(T,S)  \label{eq:diffusion}
# Line 1213  In $p$-coordinates, the upper boundary a Line 1219  In $p$-coordinates, the upper boundary a
1219  surface ($\phi $ is imposed and $\omega \neq 0$).  surface ($\phi $ is imposed and $\omega \neq 0$).
1220    
1221  \subsubsection{Splitting the geo-potential}  \subsubsection{Splitting the geo-potential}
1222    \label{sec:hpe-p-geo-potential-split}
1223    
1224  For the purposes of initialization and reducing round-off errors, the model  For the purposes of initialization and reducing round-off errors, the model
1225  deals with perturbations from reference (or ``standard'') profiles. For  deals with perturbations from reference (or ``standard'') profiles. For
# Line 1485  u=r\cos \varphi \frac{D\lambda }{Dt} Line 1492  u=r\cos \varphi \frac{D\lambda }{Dt}
1492  \end{equation*}  \end{equation*}
1493    
1494  \begin{equation*}  \begin{equation*}
1495  v=r\frac{D\varphi }{Dt}\qquad  v=r\frac{D\varphi }{Dt}
1496  \end{equation*}  \end{equation*}
 $\qquad \qquad \qquad \qquad $  
1497    
1498  \begin{equation*}  \begin{equation*}
1499  \dot{r}=\frac{Dr}{Dt}  \dot{r}=\frac{Dr}{Dt}
# Line 1497  Here $\varphi $ is the latitude, $\lambd Line 1503  Here $\varphi $ is the latitude, $\lambd
1503  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
1504  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.
1505    
1506  The `grad' ($\nabla $) and `div' ($\nabla $.) operators are defined by, in  The `grad' ($\nabla $) and `div' ($\nabla\cdot$) operators are defined by, in
1507  spherical coordinates:  spherical coordinates:
1508    
1509  \begin{equation*}  \begin{equation*}
# Line 1507  spherical coordinates: Line 1513  spherical coordinates:
1513  \end{equation*}  \end{equation*}
1514    
1515  \begin{equation*}  \begin{equation*}
1516  \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
1517  \lambda }+\frac{\partial }{\partial \varphi }\left( v\cos \varphi \right) \right\}  \lambda }+\frac{\partial }{\partial \varphi }\left( v\cos \varphi \right) \right\}
1518  +\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}
1519  \end{equation*}  \end{equation*}

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