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% $Header$ |
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% $Name$ |
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\section{Example: 4$^\circ$ Global Climatological Ocean Simulation} |
\section[Global Ocean MITgcm Example]{Global Ocean Simulation at $4^\circ$ Resolution} |
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%\label{www:tutorials} |
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\label{sec:eg-global} |
\label{sec:eg-global} |
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\begin{rawhtml} |
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<!-- CMIREDIR:eg-global: --> |
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\end{rawhtml} |
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\begin{center} |
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(in directory: {\it verification/tutorial\_global\_oce\_latlon/}) |
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\end{center} |
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\bodytext{bgcolor="#FFFFFFFF"} |
\bodytext{bgcolor="#FFFFFFFF"} |
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\noindent {\bf WARNING: the description of this experiment is not up-to-date. |
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In particular, most of the parameters description corresponds to an older |
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version of {\it verification/exp2} instead of the current tutorial}\\ |
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%\begin{center} |
%\begin{center} |
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%{\Large \bf Using MITgcm to Simulate Global Climatological Ocean Circulation |
%{\Large \bf Using MITgcm to Simulate Global Climatological Ocean Circulation |
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%At Four Degree Resolution with Asynchronous Time Stepping} |
%At Four Degree Resolution with Asynchronous Time Stepping} |
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%{\large May 2001} |
%{\large May 2001} |
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%\end{center} |
%\end{center} |
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\subsection{Introduction} |
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This document describes the third example MITgcm experiment. The first |
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two examples illustrated how to configure the code for hydrostatic idealized |
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geophysical fluids simulations. This example illustrates the use of |
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the MITgcm for large scale ocean circulation simulation. |
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\subsection{Overview} |
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This example experiment demonstrates using the MITgcm to simulate |
This example experiment demonstrates using the MITgcm to simulate |
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the planetary ocean circulation. The simulation is configured |
the planetary ocean circulation. The simulation is configured |
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with realistic geography and bathymetry on a |
with realistic geography and bathymetry on a |
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$4^{\circ} \times 4^{\circ}$ spherical polar grid. |
$4^{\circ} \times 4^{\circ}$ spherical polar grid. |
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The files for this experiment are in the verification directory |
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under tutorial\_global\_oce\_latlon. |
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Twenty levels are used in the vertical, ranging in thickness |
Twenty levels are used in the vertical, ranging in thickness |
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from $50\,{\rm m}$ at the surface to $815\,{\rm m}$ at depth, |
from $50\,{\rm m}$ at the surface to $815\,{\rm m}$ at depth, |
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giving a maximum model depth of $6\,{\rm km}$. |
giving a maximum model depth of $6\,{\rm km}$. |
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can be integrated forward for thousands of years on a single |
can be integrated forward for thousands of years on a single |
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processor desktop computer. |
processor desktop computer. |
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\\ |
\\ |
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\subsection{Overview} |
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%\label{www:tutorials} |
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The model is forced with climatological wind stress data and surface |
The model is forced with climatological wind stress data and surface |
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flux data from DaSilva \cite{DaSilva94}. Climatological data |
flux data from DaSilva \cite{DaSilva94}. Climatological data |
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in the model surface layer. |
in the model surface layer. |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:global_forcing} |
\label{eq:eg-global-global_forcing} |
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\label{EQ:global_forcing_fu} |
\label{eq:eg-global-global_forcing_fu} |
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{\cal F}_{u} & = & \frac{\tau_{x}}{\rho_{0} \Delta z_{s}} |
{\cal F}_{u} & = & \frac{\tau_{x}}{\rho_{0} \Delta z_{s}} |
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\\ |
\\ |
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\label{EQ:global_forcing_fv} |
\label{eq:eg-global-global_forcing_fv} |
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{\cal F}_{v} & = & \frac{\tau_{y}}{\rho_{0} \Delta z_{s}} |
{\cal F}_{v} & = & \frac{\tau_{y}}{\rho_{0} \Delta z_{s}} |
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\\ |
\\ |
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\label{EQ:global_forcing_ft} |
\label{eq:eg-global-global_forcing_ft} |
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{\cal F}_{\theta} & = & - \lambda_{\theta} ( \theta - \theta^{\ast} ) |
{\cal F}_{\theta} & = & - \lambda_{\theta} ( \theta - \theta^{\ast} ) |
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- \frac{1}{C_{p} \rho_{0} \Delta z_{s}}{\cal Q} |
- \frac{1}{C_{p} \rho_{0} \Delta z_{s}}{\cal Q} |
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\\ |
\\ |
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\label{EQ:global_forcing_fs} |
\label{eq:eg-global-global_forcing_fs} |
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{\cal F}_{s} & = & - \lambda_{s} ( S - S^{\ast} ) |
{\cal F}_{s} & = & - \lambda_{s} ( S - S^{\ast} ) |
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+ \frac{S_{0}}{\Delta z_{s}}({\cal E} - {\cal P} - {\cal R}) |
+ \frac{S_{0}}{\Delta z_{s}}({\cal E} - {\cal P} - {\cal R}) |
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\end{eqnarray} |
\end{eqnarray} |
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($\theta^{\ast}$ and $Q$) have units of $^{\circ}{\rm C}$ and ${\rm W}~{\rm m}^{-2}$ |
($\theta^{\ast}$ and $Q$) have units of $^{\circ}{\rm C}$ and ${\rm W}~{\rm m}^{-2}$ |
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respectively. The salinity forcing fields ($S^{\ast}$ and |
respectively. The salinity forcing fields ($S^{\ast}$ and |
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$\cal{E}-\cal{P}-\cal{R}$) have units of ${\rm ppt}$ and ${\rm m}~{\rm s}^{-1}$ |
$\cal{E}-\cal{P}-\cal{R}$) have units of ${\rm ppt}$ and ${\rm m}~{\rm s}^{-1}$ |
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respectively. |
respectively. The source files and procedures for ingesting this data into the |
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simulation are described in the experiment configuration discussion in section |
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\ref{sec:eg-global-clim_ocn_examp_exp_config}. |
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Figures (\ref{FIG:sim_config_tclim}-\ref{FIG:sim_config_empmr}) show the |
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relaxation temperature ($\theta^{\ast}$) and salinity ($S^{\ast}$) fields, |
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the wind stress components ($\tau_x$ and $\tau_y$), the heat flux ($Q$) |
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and the net fresh water flux (${\cal E} - {\cal P} - {\cal R}$) used |
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in equations \ref{EQ:global_forcing_fu}-\ref{EQ:global_forcing_fs}. The figures |
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also indicate the lateral extent and coastline used in the experiment. |
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Figure ({\ref{FIG:model_bathymetry}) shows the depth contours of the model |
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domain. |
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\subsection{Discrete Numerical Configuration} |
\subsection{Discrete Numerical Configuration} |
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%\label{www:tutorials} |
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The model is configured in hydrostatic form. The domain is discretised with |
The model is configured in hydrostatic form. The domain is discretised with |
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$x$ and $y$ are initialized according to |
$x$ and $y$ are initialized according to |
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\begin{eqnarray} |
\begin{eqnarray} |
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x=r\cos(\phi),~\Delta x & = &r\cos(\Delta \phi) \\ |
x=r\cos(\phi),~\Delta x & = &r\cos(\Delta \phi) \\ |
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y=r\lambda,~\Delta x &= &r\Delta \lambda |
y=r\lambda,~\Delta y &= &r\Delta \lambda |
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\end{eqnarray} |
\end{eqnarray} |
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Arctic polar regions are not |
Arctic polar regions are not |
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\Delta z_{18}=725\,{\rm m},\, |
\Delta z_{18}=725\,{\rm m},\, |
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\Delta z_{19}=775\,{\rm m},\, |
\Delta z_{19}=775\,{\rm m},\, |
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\Delta z_{20}=815\,{\rm m} |
\Delta z_{20}=815\,{\rm m} |
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$ (here the numeric subscript indicates the model level index number, ${\tt k}$). |
$ (here the numeric subscript indicates the model level index number, ${\tt k}$) to |
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give a total depth, $H$, of $-5450{\rm m}$. |
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The implicit free surface form of the pressure equation described in Marshall et. al |
The implicit free surface form of the pressure equation described in Marshall et. al |
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\cite{Marshall97a} is employed. A Laplacian operator, $\nabla^2$, provides viscous |
\cite{marshall:97a} is employed. A Laplacian operator, $\nabla^2$, provides viscous |
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dissipation. Thermal and haline diffusion is also represented by a Laplacian operator. |
dissipation. Thermal and haline diffusion is also represented by a Laplacian operator. |
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Wind-stress forcing is added to the momentum equations for both |
Wind-stress forcing is added to the momentum equations in (\ref{eq:eg-global-model_equations}) |
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the zonal flow, $u$ and the meridional flow $v$, according to equations |
for both the zonal flow, $u$ and the meridional flow $v$, according to equations |
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(\ref{EQ:global_forcing_fu}) and (\ref{EQ:global_forcing_fv}). |
(\ref{eq:eg-global-global_forcing_fu}) and (\ref{eq:eg-global-global_forcing_fv}). |
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Thermodynamic forcing inputs are added to the equations for |
Thermodynamic forcing inputs are added to the equations |
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in (\ref{eq:eg-global-model_equations}) for |
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potential temperature, $\theta$, and salinity, $S$, according to equations |
potential temperature, $\theta$, and salinity, $S$, according to equations |
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(\ref{EQ:global_forcing_ft}) and (\ref{EQ:global_forcing_fs}). |
(\ref{eq:eg-global-global_forcing_ft}) and (\ref{eq:eg-global-global_forcing_fs}). |
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This produces a set of equations solved in this configuration as follows: |
This produces a set of equations solved in this configuration as follows: |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:model_equations} |
\label{eq:eg-global-model_equations} |
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\frac{Du}{Dt} - fv + |
\frac{Du}{Dt} - fv + |
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\frac{1}{\rho}\frac{\partial p^{'}}{\partial x} - |
\frac{1}{\rho}\frac{\partial p^{'}}{\partial x} - |
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\nabla_{h}\cdot A_{h}\nabla_{h}u - |
\nabla_{h}\cdot A_{h}\nabla_{h}u - |
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$v=\frac{Dy}{Dt}=r \frac{D \phi}{Dt}$ |
$v=\frac{Dy}{Dt}=r \frac{D \phi}{Dt}$ |
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are the zonal and meridional components of the |
are the zonal and meridional components of the |
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flow vector, $\vec{u}$, on the sphere. As described in |
flow vector, $\vec{u}$, on the sphere. As described in |
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MITgcm Numerical Solution Procedure \cite{MITgcm_Numerical_Scheme}, the time |
MITgcm Numerical Solution Procedure \ref{chap:discretization}, the time |
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evolution of potential temperature, $\theta$, equation is solved prognostically. |
evolution of potential temperature, $\theta$, equation is solved prognostically. |
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The total pressure, $p$, is diagnosed by summing pressure due to surface |
The total pressure, $p$, is diagnosed by summing pressure due to surface |
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elevation $\eta$ and the hydrostatic pressure. |
elevation $\eta$ and the hydrostatic pressure. |
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\\ |
\\ |
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\subsubsection{Numerical Stability Criteria} |
\subsubsection{Numerical Stability Criteria} |
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%\label{www:tutorials} |
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The Laplacian dissipation coefficient, $A_{h}$, is set to $5 \times 10^5 m s^{-1}$. |
The Laplacian dissipation coefficient, $A_{h}$, is set to $5 \times 10^5 m s^{-1}$. |
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This value is chosen to yield a Munk layer width \cite{Adcroft_thesis}, |
This value is chosen to yield a Munk layer width \cite{adcroft:95}, |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:munk_layer} |
\label{eq:eg-global-munk_layer} |
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M_{w} = \pi ( \frac { A_{h} }{ \beta } )^{\frac{1}{3}} |
&& M_{w} = \pi ( \frac { A_{h} }{ \beta } )^{\frac{1}{3}} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent of $\approx 600$km. This is greater than the model |
\noindent of $\approx 600$km. This is greater than the model |
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\noindent The model is stepped forward with a |
\noindent The model is stepped forward with a |
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time step $\delta t_{\theta}=30~{\rm hours}$ for thermodynamic variables and |
time step $\delta t_{\theta}=30~{\rm hours}$ for thermodynamic variables and |
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$\delta t_{v}=40~{\rm minutes}$ for momentum terms. With this time step, the stability |
$\delta t_{v}=40~{\rm minutes}$ for momentum terms. With this time step, the stability |
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parameter to the horizontal Laplacian friction \cite{Adcroft_thesis} |
parameter to the horizontal Laplacian friction \cite{adcroft:95} |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability} |
\label{eq:eg-global-laplacian_stability} |
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S_{l} = 4 \frac{A_{h} \delta t_{v}}{{\Delta x}^2} |
&& S_{l} = 4 \frac{A_{h} \delta t_{v}}{{\Delta x}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent evaluates to 0.16 at a latitude of $\phi=80^{\circ}$, which is below the |
\noindent evaluates to 0.16 at a latitude of $\phi=80^{\circ}$, which is below the |
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\noindent The vertical dissipation coefficient, $A_{z}$, is set to |
\noindent The vertical dissipation coefficient, $A_{z}$, is set to |
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$1\times10^{-3} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
$1\times10^{-3} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability_z} |
\label{eq:eg-global-laplacian_stability_z} |
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S_{l} = 4 \frac{A_{z} \delta t_{v}}{{\Delta z}^2} |
S_{l} = 4 \frac{A_{z} \delta t_{v}}{{\Delta z}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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related to $K_{h}$ will be at $\phi=80^{\circ}$ where $\Delta x \approx 77 {\rm km}$. |
related to $K_{h}$ will be at $\phi=80^{\circ}$ where $\Delta x \approx 77 {\rm km}$. |
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Here the stability parameter |
Here the stability parameter |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability_xtheta} |
\label{eq:eg-global-laplacian_stability_xtheta} |
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S_{l} = \frac{4 K_{h} \delta t_{\theta}}{{\Delta x}^2} |
S_{l} = \frac{4 K_{h} \delta t_{\theta}}{{\Delta x}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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evaluates to $0.07$, well below the stability limit of $S_{l} \approx 0.5$. The |
evaluates to $0.07$, well below the stability limit of $S_{l} \approx 0.5$. The |
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stability parameter related to $K_{z}$ |
stability parameter related to $K_{z}$ |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability_ztheta} |
\label{eq:eg-global-laplacian_stability_ztheta} |
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S_{l} = \frac{4 K_{z} \delta t_{\theta}}{{\Delta z}^2} |
S_{l} = \frac{4 K_{z} \delta t_{\theta}}{{\Delta z}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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evaluates to $0.005$ for $\min(\Delta z)=50{\rm m}$, well below the stability limit |
evaluates to $0.005$ for $\min(\Delta z)=50{\rm m}$, well below the stability limit |
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\\ |
\\ |
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\noindent The numerical stability for inertial oscillations |
\noindent The numerical stability for inertial oscillations |
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\cite{Adcroft_thesis} |
\cite{adcroft:95} |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:inertial_stability} |
\label{eq:eg-global-inertial_stability} |
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S_{i} = f^{2} {\delta t_v}^2 |
S_{i} = f^{2} {\delta t_v}^2 |
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\end{eqnarray} |
\end{eqnarray} |
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the $S_{i} < 1$ upper limit for stability. |
the $S_{i} < 1$ upper limit for stability. |
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\\ |
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\noindent The advective CFL \cite{Adcroft_thesis} for a extreme maximum |
\noindent The advective CFL \cite{adcroft:95} for a extreme maximum |
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horizontal flow |
horizontal flow |
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speed of $ | \vec{u} | = 2 ms^{-1}$ |
speed of $ | \vec{u} | = 2 ms^{-1}$ |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:cfl_stability} |
\label{eq:eg-global-cfl_stability} |
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S_{a} = \frac{| \vec{u} | \delta t_{v}}{ \Delta x} |
S_{a} = \frac{| \vec{u} | \delta t_{v}}{ \Delta x} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent The stability parameter for internal gravity waves propagating |
\noindent The stability parameter for internal gravity waves propagating |
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with a maximum speed of $c_{g}=10~{\rm ms}^{-1}$ |
with a maximum speed of $c_{g}=10~{\rm ms}^{-1}$ |
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\cite{Adcroft_thesis} |
\cite{adcroft:95} |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:cfl_stability} |
\label{eq:eg-global-gfl_stability} |
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S_{c} = \frac{c_{g} \delta t_{v}}{ \Delta x} |
S_{c} = \frac{c_{g} \delta t_{v}}{ \Delta x} |
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\end{eqnarray} |
\end{eqnarray} |
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stability limit of 0.5. |
stability limit of 0.5. |
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\subsection{Experiment Configuration} |
\subsection{Experiment Configuration} |
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\label{SEC:clim_ocn_examp_exp_config} |
%\label{www:tutorials} |
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\label{sec:eg-global-clim_ocn_examp_exp_config} |
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The model configuration for this experiment resides under the |
The model configuration for this experiment resides under the |
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directory {\it verification/exp2/}. The experiment files |
directory {\it tutorial\_examples/global\_ocean\_circulation/}. |
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The experiment files |
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\begin{itemize} |
\begin{itemize} |
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\item {\it input/data} |
\item {\it input/data} |
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\item {\it input/data.pkg} |
\item {\it input/data.pkg} |
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experiments. Below we describe the customizations |
experiments. Below we describe the customizations |
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to these files associated with this experiment. |
to these files associated with this experiment. |
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\subsubsection{File {\it input/data}} |
\subsubsection{Driving Datasets} |
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%\label{www:tutorials} |
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This file, reproduced completely below, specifies the main parameters |
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for the experiment. The parameters that are significant for this configuration |
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are |
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\begin{itemize} |
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\item Lines 7-10 and 11-14 |
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\begin{verbatim} tRef= 16.0 , 15.2 , 14.5 , 13.9 , 13.3 , \end{verbatim} |
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$\cdots$ \\ |
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set reference values for potential |
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temperature and salinity at each model level in units of $^{\circ}$C and |
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${\rm ppt}$. The entries are ordered from surface to depth. |
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Density is calculated from anomalies at each level evaluated |
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with respect to the reference values set here.\\ |
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\fbox{ |
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\begin{minipage}{5.0in} |
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{\it S/R INI\_THETA}({\it ini\_theta.F}) |
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\end{minipage} |
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} |
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\item Line 15, |
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\begin{verbatim} viscAz=1.E-3, \end{verbatim} |
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this line sets the vertical Laplacian dissipation coefficient to |
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$1 \times 10^{-3} {\rm m^{2}s^{-1}}$. Boundary conditions |
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for this operator are specified later. This variable is copied into |
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model general vertical coordinate variable {\bf viscAr}. |
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\fbox{ |
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\begin{minipage}{5.0in} |
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{\it S/R CALC\_DIFFUSIVITY}({\it calc\_diffusivity.F}) |
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\end{minipage} |
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} |
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\item Line 16, |
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\begin{verbatim} |
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viscAh=5.E5, |
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\end{verbatim} |
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this line sets the horizontal Laplacian frictional dissipation coefficient to |
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$5 \times 10^{5} {\rm m^{2}s^{-1}}$. Boundary conditions |
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for this operator are specified later. |
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\item Lines 17, |
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\begin{verbatim} |
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no_slip_sides=.FALSE. |
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\end{verbatim} |
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this line selects a free-slip lateral boundary condition for |
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the horizontal Laplacian friction operator |
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e.g. $\frac{\partial u}{\partial y}$=0 along boundaries in $y$ and |
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$\frac{\partial v}{\partial x}$=0 along boundaries in $x$. |
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\item Lines 9, |
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\begin{verbatim} |
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no_slip_bottom=.TRUE. |
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\end{verbatim} |
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this line selects a no-slip boundary condition for bottom |
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boundary condition in the vertical Laplacian friction operator |
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e.g. $u=v=0$ at $z=-H$, where $H$ is the local depth of the domain. |
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\item Line 19, |
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\begin{verbatim} |
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diffKhT=1.E3, |
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\end{verbatim} |
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this line sets the horizontal diffusion coefficient for temperature |
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to $1000\,{\rm m^{2}s^{-1}}$. The boundary condition on this |
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operator is $\frac{\partial}{\partial x}=\frac{\partial}{\partial y}=0$ on |
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all boundaries. |
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\item Line 20, |
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\begin{verbatim} |
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diffKzT=3.E-5, |
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\end{verbatim} |
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this line sets the vertical diffusion coefficient for temperature |
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to $3 \times 10^{-5}\,{\rm m^{2}s^{-1}}$. The boundary |
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condition on this operator is $\frac{\partial}{\partial z}=0$ at both |
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the upper and lower boundaries. |
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\item Line 21, |
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\begin{verbatim} |
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diffKhS=1.E3, |
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\end{verbatim} |
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this line sets the horizontal diffusion coefficient for salinity |
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to $1000\,{\rm m^{2}s^{-1}}$. The boundary condition on this |
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operator is $\frac{\partial}{\partial x}=\frac{\partial}{\partial y}=0$ on |
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all boundaries. |
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\item Line 22, |
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\begin{verbatim} |
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diffKzS=3.E-5, |
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\end{verbatim} |
|
|
this line sets the vertical diffusion coefficient for salinity |
|
|
to $3 \times 10^{-5}\,{\rm m^{2}s^{-1}}$. The boundary |
|
|
condition on this operator is $\frac{\partial}{\partial z}=0$ at both |
|
|
the upper and lower boundaries. |
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|
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\item Lines 23-26 |
|
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\begin{verbatim} |
|
|
beta=1.E-11, |
|
|
\end{verbatim} |
|
|
\vspace{-5mm}$\cdots$\\ |
|
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These settings do not apply for this experiment. |
|
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|
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\item Line 27, |
|
|
\begin{verbatim} |
|
|
gravity=9.81, |
|
|
\end{verbatim} |
|
|
Sets the gravitational acceleration coefficient to $9.81{\rm m}{\rm s}^{-1}$.\\ |
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R CALC\_PHI\_HYD}~({\it calc\_phi\_hyd.F})\\ |
|
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{\it S/R INI\_CG2D}~({\it ini\_cg2d.F})\\ |
|
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{\it S/R INI\_CG3D}~({\it ini\_cg3d.F})\\ |
|
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{\it S/R INI\_PARMS}~({\it ini\_parms.F})\\ |
|
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{\it S/R SOLVE\_FOR\_PRESSURE}~({\it solve\_for\_pressure.F}) |
|
|
\end{minipage} |
|
|
} |
|
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|
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|
|
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\item Line 28-29, |
|
|
\begin{verbatim} |
|
|
rigidLid=.FALSE., |
|
|
implicitFreeSurface=.TRUE., |
|
|
\end{verbatim} |
|
|
Selects the barotropic pressure equation to be the implicit free surface |
|
|
formulation. |
|
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|
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|
\item Line 30, |
|
|
\begin{verbatim} |
|
|
eosType='POLY3', |
|
|
\end{verbatim} |
|
|
Selects the third order polynomial form of the equation of state.\\ |
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R FIND\_RHO}~({\it find\_rho.F})\\ |
|
|
{\it S/R FIND\_ALPHA}~({\it find\_alpha.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 31, |
|
|
\begin{verbatim} |
|
|
readBinaryPrec=32, |
|
|
\end{verbatim} |
|
|
Sets format for reading binary input datasets holding model fields to |
|
|
use 32-bit representation for floating-point numbers.\\ |
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R READ\_WRITE\_FLD}~({\it read\_write\_fld.F})\\ |
|
|
{\it S/R READ\_WRITE\_REC}~({\it read\_write\_rec.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 36, |
|
|
\begin{verbatim} |
|
|
cg2dMaxIters=1000, |
|
|
\end{verbatim} |
|
|
Sets maximum number of iterations the two-dimensional, conjugate |
|
|
gradient solver will use, {\bf irrespective of convergence |
|
|
criteria being met}.\\ |
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R CG2D}~({\it cg2d.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 37, |
|
|
\begin{verbatim} |
|
|
cg2dTargetResidual=1.E-13, |
|
|
\end{verbatim} |
|
|
Sets the tolerance which the two-dimensional, conjugate |
|
|
gradient solver will use to test for convergence in equation |
|
|
\ref{EQ:congrad_2d_resid} to $1 \times 10^{-13}$. |
|
|
Solver will iterate until |
|
|
tolerance falls below this value or until the maximum number of |
|
|
solver iterations is reached.\\ |
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R CG2D}~({\it cg2d.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 42, |
|
|
\begin{verbatim} |
|
|
startTime=0, |
|
|
\end{verbatim} |
|
|
Sets the starting time for the model internal time counter. |
|
|
When set to non-zero this option implicitly requests a |
|
|
checkpoint file be read for initial state. |
|
|
By default the checkpoint file is named according to |
|
|
the integer number of time steps in the {\bf startTime} value. |
|
|
The internal time counter works in seconds. |
|
|
|
|
|
\item Line 43, |
|
|
\begin{verbatim} |
|
|
endTime=2808000., |
|
|
\end{verbatim} |
|
|
Sets the time (in seconds) at which this simulation will terminate. |
|
|
At the end of a simulation a checkpoint file is automatically |
|
|
written so that a numerical experiment can consist of multiple |
|
|
stages. |
|
|
|
|
|
\item Line 44, |
|
|
\begin{verbatim} |
|
|
#endTime=62208000000, |
|
|
\end{verbatim} |
|
|
A commented out setting for endTime for a 2000 year simulation. |
|
|
|
|
|
\item Line 45, |
|
|
\begin{verbatim} |
|
|
deltaTmom=2400.0, |
|
|
\end{verbatim} |
|
|
Sets the timestep $\delta t_{v}$ used in the momentum equations to |
|
|
$20~{\rm mins}$. |
|
|
See section \ref{SEC:mom_time_stepping}. |
|
|
|
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R TIMESTEP}({\it timestep.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 46, |
|
|
\begin{verbatim} |
|
|
tauCD=321428., |
|
|
\end{verbatim} |
|
|
Sets the D-grid to C-grid coupling time scale $\tau_{CD}$ used in the momentum equations. |
|
|
See section \ref{SEC:cd_scheme}. |
|
|
|
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R INI\_PARMS}({\it ini\_parms.F})\\ |
|
|
{\it S/R CALC\_MOM\_RHS}({\it calc\_mom\_rhs.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 47, |
|
|
\begin{verbatim} |
|
|
deltaTtracer=108000., |
|
|
\end{verbatim} |
|
|
Sets the default timestep, $\delta t_{\theta}$, for tracer equations to |
|
|
$30~{\rm hours}$. |
|
|
See section \ref{SEC:tracer_time_stepping}. |
|
|
|
|
|
\fbox{ |
|
|
\begin{minipage}{5.0in} |
|
|
{\it S/R TIMESTEP\_TRACER}({\it timestep\_tracer.F}) |
|
|
\end{minipage} |
|
|
} |
|
|
|
|
|
\item Line 47, |
|
|
\begin{verbatim} |
|
|
bathyFile='topog.box' |
|
|
\end{verbatim} |
|
|
This line specifies the name of the file from which the domain |
|
|
bathymetry is read. This file is a two-dimensional ($x,y$) map of |
|
|
depths. This file is assumed to contain 64-bit binary numbers |
|
|
giving the depth of the model at each grid cell, ordered with the x |
|
|
coordinate varying fastest. The points are ordered from low coordinate |
|
|
to high coordinate for both axes. The units and orientation of the |
|
|
depths in this file are the same as used in the MITgcm code. In this |
|
|
experiment, a depth of $0m$ indicates a solid wall and a depth |
|
|
of $-2000m$ indicates open ocean. The matlab program |
|
|
{\it input/gendata.m} shows an example of how to generate a |
|
|
bathymetry file. |
|
|
|
|
|
|
|
|
\item Line 50, |
|
|
\begin{verbatim} |
|
|
zonalWindFile='windx.sin_y' |
|
|
\end{verbatim} |
|
|
This line specifies the name of the file from which the x-direction |
|
|
surface wind stress is read. This file is also a two-dimensional |
|
|
($x,y$) map and is enumerated and formatted in the same manner as the |
|
|
bathymetry file. The matlab program {\it input/gendata.m} includes example |
|
|
code to generate a valid |
|
|
{\bf zonalWindFile} |
|
|
file. |
|
346 |
|
|
347 |
\end{itemize} |
Figures ({\it --- missing figures ---}) |
348 |
|
%(\ref{fig:sim_config_tclim}-\ref{fig:sim_config_empmr}) |
349 |
|
show the relaxation temperature ($\theta^{\ast}$) and salinity ($S^{\ast}$) |
350 |
|
fields, the wind stress components ($\tau_x$ and $\tau_y$), the heat flux ($Q$) |
351 |
|
and the net fresh water flux (${\cal E} - {\cal P} - {\cal R}$) used |
352 |
|
in equations |
353 |
|
(\ref{eq:eg-global-global_forcing_fu}-\ref{eq:eg-global-global_forcing_fs}). |
354 |
|
The figures also indicate the lateral extent and coastline used in the |
355 |
|
experiment. Figure ({\it --- missing figure --- }) %ref{fig:model_bathymetry}) |
356 |
|
shows the depth contours of the model domain. |
357 |
|
|
358 |
\noindent other lines in the file {\it input/data} are standard values |
\subsubsection{File {\it input/data}} |
359 |
that are described in the MITgcm Getting Started and MITgcm Parameters |
%\label{www:tutorials} |
|
notes. |
|
360 |
|
|
361 |
\begin{small} |
\input{s_examples/global_oce_latlon/inp_data} |
|
\input{part3/case_studies/climatalogical_ogcm/input/data} |
|
|
\end{small} |
|
362 |
|
|
363 |
\subsubsection{File {\it input/data.pkg}} |
\subsubsection{File {\it input/data.pkg}} |
364 |
|
%\label{www:tutorials} |
365 |
|
|
366 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
367 |
customisations for this experiment. |
customisations for this experiment. |
368 |
|
|
369 |
\subsubsection{File {\it input/eedata}} |
\subsubsection{File {\it input/eedata}} |
370 |
|
%\label{www:tutorials} |
371 |
|
|
372 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
373 |
customisations for this experiment. |
customisations for this experiment. |
374 |
|
|
375 |
\subsubsection{File {\it input/windx.sin\_y}} |
\subsubsection{File {\it input/windx.sin\_y}} |
376 |
|
%\label{www:tutorials} |
377 |
|
|
378 |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
379 |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$. |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$. |
384 |
code for creating the {\it input/windx.sin\_y} file. |
code for creating the {\it input/windx.sin\_y} file. |
385 |
|
|
386 |
\subsubsection{File {\it input/topog.box}} |
\subsubsection{File {\it input/topog.box}} |
387 |
|
%\label{www:tutorials} |
388 |
|
|
389 |
|
|
390 |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
396 |
code for creating the {\it input/topog.box} file. |
code for creating the {\it input/topog.box} file. |
397 |
|
|
398 |
\subsubsection{File {\it code/SIZE.h}} |
\subsubsection{File {\it code/SIZE.h}} |
399 |
|
%\label{www:tutorials} |
400 |
|
|
401 |
Two lines are customized in this file for the current experiment |
Two lines are customized in this file for the current experiment |
402 |
|
|
419 |
\end{itemize} |
\end{itemize} |
420 |
|
|
421 |
\begin{small} |
\begin{small} |
422 |
\input{part3/case_studies/climatalogical_ogcm/code/SIZE.h} |
\input{s_examples/global_oce_latlon/code/SIZE.h} |
423 |
\end{small} |
\end{small} |
424 |
|
|
425 |
\subsubsection{File {\it code/CPP\_OPTIONS.h}} |
\subsubsection{File {\it code/CPP\_OPTIONS.h}} |
426 |
|
%\label{www:tutorials} |
427 |
|
|
428 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
429 |
customisations for this experiment. |
customisations for this experiment. |
430 |
|
|
431 |
|
|
432 |
\subsubsection{File {\it code/CPP\_EEOPTIONS.h}} |
\subsubsection{File {\it code/CPP\_EEOPTIONS.h}} |
433 |
|
%\label{www:tutorials} |
434 |
|
|
435 |
This file uses standard default values and does not contain |
This file uses standard default values and does not contain |
436 |
customisations for this experiment. |
customisations for this experiment. |
437 |
|
|
438 |
\subsubsection{Other Files } |
\subsubsection{Other Files } |
439 |
|
%\label{www:tutorials} |
440 |
|
|
441 |
Other files relevant to this experiment are |
Other files relevant to this experiment are |
442 |
\begin{itemize} |
\begin{itemize} |