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\section{Example: Four layer Baroclinic Ocean Gyre In Spherical Coordinates} |
\section{Four Layer Baroclinic Ocean Gyre In Spherical Coordinates} |
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\label{sec:eg-fourlayer} |
\label{sect:eg-fourlayer} |
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\bodytext{bgcolor="#FFFFFFFF"} |
\bodytext{bgcolor="#FFFFFFFF"} |
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This document describes an example experiment using MITgcm |
This document describes an example experiment using MITgcm |
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to simulate a baroclinic ocean gyre in spherical |
to simulate a baroclinic ocean gyre in spherical |
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polar coordinates. The barotropic |
polar coordinates. The barotropic |
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example experiment in section \ref{sec:eg-baro} |
example experiment in section \ref{sect:eg-baro} |
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ilustrated how to configure the code for a single layer |
illustrated how to configure the code for a single layer |
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simulation in a cartesian grid. In this example a similar physical problem |
simulation in a Cartesian grid. In this example a similar physical problem |
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is simulated, but the code is now configured |
is simulated, but the code is now configured |
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for four layers and in a spherical polar coordinate system. |
for four layers and in a spherical polar coordinate system. |
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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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a baroclinic, wind-forced, ocean gyre circulation. The experiment |
a baroclinic, wind-forced, ocean gyre circulation. The experiment |
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is a numerical rendition of the gyre circulation problem simliar |
is a numerical rendition of the gyre circulation problem similar |
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to the problems described analytically by Stommel in 1966 |
to the problems described analytically by Stommel in 1966 |
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\cite{Stommel66} and numerically in Holland et. al \cite{Holland75}. |
\cite{Stommel66} and numerically in Holland et. al \cite{Holland75}. |
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\\ |
\\ |
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according to latitude, $\varphi$ |
according to latitude, $\varphi$ |
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\begin{equation} |
\begin{equation} |
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\label{EQ:fcori} |
\label{EQ:eg-fourlayer-fcori} |
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f(\varphi) = 2 \Omega \sin( \varphi ) |
f(\varphi) = 2 \Omega \sin( \varphi ) |
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\end{equation} |
\end{equation} |
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$\tau_0$ is set to $0.1N m^{-2}$. |
$\tau_0$ is set to $0.1N m^{-2}$. |
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\\ |
\\ |
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Figure \ref{FIG:simulation_config} |
Figure \ref{FIG:eg-fourlayer-simulation_config} |
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summarises the configuration simulated. |
summarizes the configuration simulated. |
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In contrast to the example in section \ref{sec:eg-baro}, the |
In contrast to the example in section \ref{sect:eg-baro}, the |
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current experiment simulates a spherical polar domain. As indicated |
current experiment simulates a spherical polar domain. As indicated |
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by the axes in the lower left of the figure the model code works internally |
by the axes in the lower left of the figure the model code works internally |
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in a locally orthoganal coordinate $(x,y,z)$. For this experiment description |
in a locally orthogonal coordinate $(x,y,z)$. For this experiment description |
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of this document the local orthogonal model coordinate $(x,y,z)$ is synonomous |
the local orthogonal model coordinate $(x,y,z)$ is synonymous |
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with the spherical polar coordinate shown in figure |
with the coordinates $(\lambda,\varphi,r)$ shown in figure |
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\ref{fig:spherical-polar-coord} |
\ref{fig:spherical-polar-coord} |
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\\ |
\\ |
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linear |
linear |
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\begin{equation} |
\begin{equation} |
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\label{EQ:linear1_eos} |
\label{EQ:eg-fourlayer-linear1_eos} |
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\rho = \rho_{0} ( 1 - \alpha_{\theta}\theta^{'} ) |
\rho = \rho_{0} ( 1 - \alpha_{\theta}\theta^{'} ) |
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\end{equation} |
\end{equation} |
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\noindent which is implemented in the model as a density anomaly equation |
\noindent which is implemented in the model as a density anomaly equation |
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\begin{equation} |
\begin{equation} |
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\label{EQ:linear1_eos_pert} |
\label{EQ:eg-fourlayer-linear1_eos_pert} |
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\rho^{'} = -\rho_{0}\alpha_{\theta}\theta^{'} |
\rho^{'} = -\rho_{0}\alpha_{\theta}\theta^{'} |
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\end{equation} |
\end{equation} |
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imposed by setting the potential temperature, $\theta$, in each layer. |
imposed by setting the potential temperature, $\theta$, in each layer. |
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The vertical spacing, $\Delta z$, is constant and equal to $500$m. |
The vertical spacing, $\Delta z$, is constant and equal to $500$m. |
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} |
} |
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\label{FIG:simulation_config} |
\label{FIG:eg-fourlayer-simulation_config} |
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\end{figure} |
\end{figure} |
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\subsection{Equations solved} |
\subsection{Equations solved} |
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For this problem |
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The implicit free surface {\bf HPE} form of the |
the implicit free surface, {\bf HPE} (see section \ref{sect:hydrostatic_and_quasi-hydrostatic_forms}) form of the |
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equations described in Marshall et. al \cite{Marshall97a} is |
equations described in Marshall et. al \cite{marshall:97a} are |
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employed. The flow is three-dimensional with just temperature, $\theta$, as |
employed. The flow is three-dimensional with just temperature, $\theta$, as |
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an active tracer. The equation of state is linear. |
an active tracer. The equation of state is linear. |
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A horizontal laplacian operator $\nabla_{h}^2$ provides viscous |
A horizontal Laplacian operator $\nabla_{h}^2$ provides viscous |
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dissipation and provides a diffusive sub-grid scale closure for the |
dissipation and provides a diffusive sub-grid scale closure for the |
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temperature equation. A wind-stress momentum forcing is added to the momentum |
temperature equation. A wind-stress momentum forcing is added to the momentum |
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equation for the zonal flow, $u$. Other terms in the model |
equation for the zonal flow, $u$. Other terms in the model |
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are explicitly switched off for this experiement configuration (see section |
are explicitly switched off for this experiment configuration (see section |
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\ref{SEC:eg_fourl_code_config} ). This yields an active set of equations |
\ref{SEC:eg_fourl_code_config} ). This yields an active set of equations |
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solved in this configuration, written in spherical polar coordinates as |
solved in this configuration, written in spherical polar coordinates as |
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follows |
follows |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:model_equations} |
\label{EQ:eg-fourlayer-model_equations} |
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\frac{Du}{Dt} - fv + |
\frac{Du}{Dt} - fv + |
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\frac{1}{\rho}\frac{\partial p^{\prime}}{\partial \lambda} - |
\frac{1}{\rho}\frac{\partial p^{\prime}}{\partial \lambda} - |
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A_{h}\nabla_{h}^2u - A_{z}\frac{\partial^{2}u}{\partial z^{2}} |
A_{h}\nabla_{h}^2u - A_{z}\frac{\partial^{2}u}{\partial z^{2}} |
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part due to variations in density, $\rho^{\prime}$, integrated |
part due to variations in density, $\rho^{\prime}$, integrated |
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through the water column. |
through the water column. |
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The suffices ${s},{i}$ indicate surface and interior of the domain. |
The suffices ${s},{i}$ indicate surface layer and the interior of the domain. |
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The windstress forcing, ${\cal F}_{\lambda}$, is applied in the surface layer |
The windstress forcing, ${\cal F}_{\lambda}$, is applied in the surface layer |
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by a source term in the zonal momentum equation. In the ocean interior |
by a source term in the zonal momentum equation. In the ocean interior |
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this term is zero. |
this term is zero. |
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Vertically the |
Vertically the |
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model is configured with four layers with constant depth, |
model is configured with four layers with constant depth, |
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$\Delta z$, of $500$~m. The internal, locally orthogonal, model coordinate |
$\Delta z$, of $500$~m. The internal, locally orthogonal, model coordinate |
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variables $x$ and $y$ are initialised from the values of |
variables $x$ and $y$ are initialized from the values of |
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$\lambda$, $\varphi$, $\Delta \lambda$ and $\Delta \varphi$ in |
$\lambda$, $\varphi$, $\Delta \lambda$ and $\Delta \varphi$ in |
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radians according to |
radians according to |
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The procedure for generating a set of internal grid variables from a |
The procedure for generating a set of internal grid variables from a |
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spherical polar grid specification is discussed in section |
spherical polar grid specification is discussed in section |
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\ref{sec:spatial_discrete_horizontal_grid}. |
\ref{sect:spatial_discrete_horizontal_grid}. |
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\noindent\fbox{ \begin{minipage}{5.5in} |
\noindent\fbox{ \begin{minipage}{5.5in} |
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{\em S/R INI\_SPHERICAL\_POLAR\_GRID} ({\em |
{\em S/R INI\_SPHERICAL\_POLAR\_GRID} ({\em |
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As described in \ref{sec:tracer_equations}, the time evolution of potential |
As described in \ref{sect:tracer_equations}, the time evolution of potential |
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temperature, |
temperature, |
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$\theta$, (equation \ref{eq:eg_fourl_theta}) |
$\theta$, (equation \ref{eq:eg_fourl_theta}) |
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is evaluated prognostically. The centered second-order scheme with |
is evaluated prognostically. The centered second-order scheme with |
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Adams-Bashforth time stepping described in section |
Adams-Bashforth time stepping described in section |
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\ref{sec:tracer_equations_abII} is used to step forward the temperature |
\ref{sect:tracer_equations_abII} is used to step forward the temperature |
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equation. The pressure forces that drive the fluid motions, ( |
equation. Prognostic terms in |
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the momentum equations are solved using flux form as |
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described in section \ref{sect:flux-form_momentum_eqautions}. |
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The pressure forces that drive the fluid motions, ( |
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$\frac{\partial p^{'}}{\partial \lambda}$ and $\frac{\partial p^{'}}{\partial \varphi}$), are found by summing pressure due to surface |
$\frac{\partial p^{'}}{\partial \lambda}$ and $\frac{\partial p^{'}}{\partial \varphi}$), are found by summing pressure due to surface |
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elevation $\eta$ and the hydrostatic pressure. The hydrostatic part of the |
elevation $\eta$ and the hydrostatic pressure. The hydrostatic part of the |
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pressure is evaluated explicitly by integrating density. The sea-surface |
pressure is diagnosed explicitly by integrating density. The sea-surface |
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height, $\eta$, is solved for implicitly as described in section |
height, $\eta$, is diagnosed using an implicit scheme. The pressure |
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\ref{sect:pressure-method-linear-backward}. |
field solution method is described in sections |
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\ref{sect:pressure-method-linear-backward} and |
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\ref{sect:finding_the_pressure_field}. |
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\subsubsection{Numerical Stability Criteria} |
\subsubsection{Numerical Stability Criteria} |
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The laplacian dissipation coefficient, $A_{h}$, is set to $400 m s^{-1}$. |
The Laplacian viscosity coefficient, $A_{h}$, is set to $400 m s^{-1}$. |
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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, |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:munk_layer} |
\label{EQ:eg-fourlayer-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 $\approx 100$km. This is greater than the model |
\noindent of $\approx 100$km. This is greater than the model |
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resolution in mid-latitudes $\Delta x$, ensuring that the frictional |
resolution in mid-latitudes |
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$\Delta x=r \cos(\varphi) \Delta \lambda \approx 80~{\rm km}$ at |
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$\varphi=45^{\circ}$, ensuring that the frictional |
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boundary layer is well resolved. |
boundary layer is well resolved. |
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\\ |
\\ |
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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 $\delta t=1200$secs. With this time step the stability |
time step $\delta t=1200$secs. 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 |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability} |
\label{EQ:eg-fourlayer-laplacian_stability} |
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S_{l} = 4 \frac{A_{h} \delta t}{{\Delta x}^2} |
S_{l} = 4 \frac{A_{h} \delta t}{{\Delta x}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent evaluates to 0.012, which is well below the 0.3 upper limit |
\noindent evaluates to 0.012, which is well below the 0.3 upper limit |
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for stability. |
for stability for this term under ABII time-stepping. |
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\\ |
\\ |
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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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$1\times10^{-2} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
$1\times10^{-2} {\rm m}^2{\rm s}^{-1}$. The associated stability limit |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:laplacian_stability_z} |
\label{EQ:eg-fourlayer-laplacian_stability_z} |
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S_{l} = 4 \frac{A_{z} \delta t}{{\Delta z}^2} |
S_{l} = 4 \frac{A_{z} \delta t}{{\Delta z}^2} |
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\end{eqnarray} |
\end{eqnarray} |
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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} |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:inertial_stability} |
\label{EQ:eg-fourlayer-inertial_stability} |
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S_{i} = f^{2} {\delta t}^2 |
S_{i} = f^{2} {\delta t}^2 |
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\end{eqnarray} |
\end{eqnarray} |
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limit for stability. |
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 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-fourlayer-cfl_stability} |
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S_{a} = \frac{| \vec{u} | \delta t}{ \Delta x} |
C_{a} = \frac{| \vec{u} | \delta t}{ \Delta x} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent evaluates to $5 \times 10^{-2}$. This is well below the stability |
\noindent evaluates to $5 \times 10^{-2}$. This is well below the stability |
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limit of 0.5. |
limit of 0.5. |
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\\ |
\\ |
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\noindent The stability parameter for internal gravity waves |
\noindent The stability parameter for internal gravity waves |
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\cite{Adcroft_thesis} |
propagating at $2~{\rm m}~{\rm s}^{-1}$ |
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\begin{eqnarray} |
\begin{eqnarray} |
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\label{EQ:igw_stability} |
\label{EQ:eg-fourlayer-igw_stability} |
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S_{c} = \frac{c_{g} \delta t}{ \Delta x} |
S_{c} = \frac{c_{g} \delta t}{ \Delta x} |
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\end{eqnarray} |
\end{eqnarray} |
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\noindent evaluates to $5 \times 10^{-2}$. This is well below the linear |
\noindent evaluates to $\approx 5 \times 10^{-2}$. This is well below the linear |
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stability limit of 0.25. |
stability limit of 0.25. |
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\subsection{Code Configuration} |
\subsection{Code Configuration} |
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\label{SEC:eg_fourl_code_config} |
\label{SEC:eg_fourl_code_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/exp1/}. The experiment files |
directory {\it verification/exp2/}. 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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\item {\it code/SIZE.h}. |
\item {\it code/SIZE.h}. |
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\end{itemize} |
\end{itemize} |
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contain the code customisations and parameter settings for this |
contain the code customisations and parameter settings for this |
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experiements. Below we describe the customisations |
experiments. Below we describe the customisations |
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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{File {\it input/data}} |
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the initial and reference values of potential temperature at each model |
the initial and reference values of potential temperature at each model |
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level in units of $^{\circ}$C. |
level in units of $^{\circ}$C. |
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The entries are ordered from surface to depth. For each |
The entries are ordered from surface to depth. For each |
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depth level the inital and reference profiles will be uniform in |
depth level the initial and reference profiles will be uniform in |
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$x$ and $y$. The values specified here are read into the |
$x$ and $y$. The values specified here are read into the |
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variable |
variable |
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{\bf |
{\bf |
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\item Line 6, |
\item Line 6, |
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\begin{verbatim} viscAz=1.E-2, \end{verbatim} |
\begin{verbatim} viscAz=1.E-2, \end{verbatim} |
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this line sets the vertical laplacian dissipation coefficient to |
this line sets the vertical Laplacian dissipation coefficient to |
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$1 \times 10^{-2} {\rm m^{2}s^{-1}}$. Boundary conditions |
$1 \times 10^{-2} {\rm m^{2}s^{-1}}$. Boundary conditions |
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for this operator are specified later. |
for this operator are specified later. |
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The variable |
The variable |
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\begin{rawhtml} <A href=../../../code_reference/vdb/names/PF.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/names/PF.htm> \end{rawhtml} |
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viscAr |
viscAr |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
}. At each time step, the viscous term contribution to the momentum equations |
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is calculated in routine |
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{\it S/R CALC\_DIFFUSIVITY}. |
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|
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\fbox{ |
\fbox{ |
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\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
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\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
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INI\_PARMS |
INI\_PARMS |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
} and applied in routines {\it CALC\_MOM\_RHS} and {\it CALC\_GW}. |
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|
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\fbox{ |
\fbox{ |
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\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
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\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
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INI\_PARMS |
INI\_PARMS |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
} and the boundary condition is evaluated in routine |
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{\it S/R CALC\_MOM\_RHS}. |
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\fbox{ |
\fbox{ |
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\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
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INI\_PARMS |
INI\_PARMS |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
} and is applied in the routine {\it S/R CALC\_MOM\_RHS}. |
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|
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\fbox{ |
\fbox{ |
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\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
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\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
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INI\_PARMS |
INI\_PARMS |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
} and used in routine {\it S/R CALC\_GT}. |
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\fbox{ \begin{minipage}{5.0in} |
\fbox{ \begin{minipage}{5.0in} |
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{\it S/R CALC\_GT}({\it calc\_gt.F}) |
{\it S/R CALC\_GT}({\it calc\_gt.F}) |
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\begin{rawhtml} <A href=../../../code_reference/vdb/names/PD.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/names/PD.htm> \end{rawhtml} |
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diffKrT |
diffKrT |
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\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
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}. |
} which is used in routine {\it S/R CALC\_DIFFUSIVITY}. |
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\fbox{ \begin{minipage}{5.0in} |
\fbox{ \begin{minipage}{5.0in} |
| 621 |
{\it S/R CALC\_DIFFUSIVITY}({\it calc\_diffusivity.F}) |
{\it S/R CALC\_DIFFUSIVITY}({\it calc\_diffusivity.F}) |
| 646 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 647 |
INI\_PARMS |
INI\_PARMS |
| 648 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 649 |
}. |
}. The routine {\it S/R FIND\_RHO} makes use of {\bf tAlpha}. |
| 650 |
|
|
| 651 |
\fbox{ |
\fbox{ |
| 652 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 675 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 676 |
INI\_PARMS |
INI\_PARMS |
| 677 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 678 |
}. |
}. The values of {\bf eosType} sets which formula in routine |
| 679 |
|
{\it FIND\_RHO} is used to calculate density. |
| 680 |
|
|
| 681 |
\fbox{ |
\fbox{ |
| 682 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 697 |
\end{verbatim} |
\end{verbatim} |
| 698 |
This line requests that the simulation be performed in a |
This line requests that the simulation be performed in a |
| 699 |
spherical polar coordinate system. It affects the interpretation of |
spherical polar coordinate system. It affects the interpretation of |
| 700 |
grid inoput parameters, for exampl {\bf delX} and {\bf delY} and |
grid input parameters, for example {\bf delX} and {\bf delY} and |
| 701 |
causes the grid generation routines to initialise an internal grid based |
causes the grid generation routines to initialize an internal grid based |
| 702 |
on spherical polar geometry. |
on spherical polar geometry. |
| 703 |
The variable |
The variable |
| 704 |
{\bf |
{\bf |
| 711 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 712 |
INI\_PARMS |
INI\_PARMS |
| 713 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 714 |
}. |
}. When set to {\bf .TRUE.} the settings of {\bf delX} and {\bf delY} are |
| 715 |
|
taken to be in degrees. These values are used in the |
| 716 |
|
routine {\it INI\_SPEHRICAL\_POLAR\_GRID}. |
| 717 |
|
|
| 718 |
\fbox{ |
\fbox{ |
| 719 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 733 |
This line sets the southern boundary of the modeled |
This line sets the southern boundary of the modeled |
| 734 |
domain to $0^{\circ}$ latitude. This value affects both the |
domain to $0^{\circ}$ latitude. This value affects both the |
| 735 |
generation of the locally orthogonal grid that the model |
generation of the locally orthogonal grid that the model |
| 736 |
uses internally and affects the initialisation of the coriolis force. |
uses internally and affects the initialization of the coriolis force. |
| 737 |
Note - it is not required to set |
Note - it is not required to set |
| 738 |
a longitude boundary, since the absolute longitude does |
a longitude boundary, since the absolute longitude does |
| 739 |
not alter the kernel equation discretisation. |
not alter the kernel equation discretisation. |
| 748 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 749 |
INI\_PARMS |
INI\_PARMS |
| 750 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 751 |
}. |
} and is used in routine {\it INI\_SPEHRICAL\_POLAR\_GRID}. |
| 752 |
|
|
| 753 |
\fbox{ |
\fbox{ |
| 754 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 778 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 779 |
INI\_PARMS |
INI\_PARMS |
| 780 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 781 |
}. |
} and is used in routine {\it INI\_SPEHRICAL\_POLAR\_GRID}. |
| 782 |
|
|
| 783 |
\fbox{ |
\fbox{ |
| 784 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 808 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 809 |
INI\_PARMS |
INI\_PARMS |
| 810 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 811 |
}. |
} and is used in routine {\it INI\_SPEHRICAL\_POLAR\_GRID}. |
| 812 |
|
|
| 813 |
\fbox{ |
\fbox{ |
| 814 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 846 |
\begin{rawhtml} <A href=../../../code_reference/vdb/names/10Y.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/names/10Y.htm> \end{rawhtml} |
| 847 |
delR |
delR |
| 848 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 849 |
}. |
} which is used in routine {\it INI\_VERTICAL\_GRID}. |
| 850 |
|
|
| 851 |
\fbox{ |
\fbox{ |
| 852 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 885 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 886 |
INI\_PARMS |
INI\_PARMS |
| 887 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 888 |
}. |
}. The bathymetry file is read in the routine {\it INI\_DEPTHS}. |
| 889 |
|
|
| 890 |
\fbox{ |
\fbox{ |
| 891 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 904 |
zonalWindFile='windx.sin_y' |
zonalWindFile='windx.sin_y' |
| 905 |
\end{verbatim} |
\end{verbatim} |
| 906 |
This line specifies the name of the file from which the x-direction |
This line specifies the name of the file from which the x-direction |
| 907 |
surface wind stress is read. This file is also a two-dimensional |
(zonal) surface wind stress is read. This file is also a two-dimensional |
| 908 |
($x,y$) map and is enumerated and formatted in the same manner as the |
($x,y$) map and is enumerated and formatted in the same manner as the |
| 909 |
bathymetry file. The matlab program {\it input/gendata.m} includes example |
bathymetry file. The matlab program {\it input/gendata.m} includes example |
| 910 |
code to generate a valid |
code to generate a valid |
| 921 |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
\begin{rawhtml} <A href=../../../code_reference/vdb/code/94.htm> \end{rawhtml} |
| 922 |
INI\_PARMS |
INI\_PARMS |
| 923 |
\begin{rawhtml} </A>\end{rawhtml} |
\begin{rawhtml} </A>\end{rawhtml} |
| 924 |
}. |
}. The wind-stress file is read in the routine |
| 925 |
|
{\it EXTERNAL\_FIELDS\_LOAD}. |
| 926 |
|
|
| 927 |
\fbox{ |
\fbox{ |
| 928 |
\begin{minipage}{5.0in} |
\begin{minipage}{5.0in} |
| 937 |
|
|
| 938 |
\end{itemize} |
\end{itemize} |
| 939 |
|
|
| 940 |
\noindent other lines in the file {\it input/data} are standard values |
\noindent other lines in the file {\it input/data} are standard values. |
|
that are described in the MITgcm Getting Started and MITgcm Parameters |
|
|
notes. |
|
| 941 |
|
|
| 942 |
\begin{rawhtml}<PRE>\end{rawhtml} |
\begin{rawhtml}<PRE>\end{rawhtml} |
| 943 |
\begin{small} |
\begin{small} |
| 958 |
\subsubsection{File {\it input/windx.sin\_y}} |
\subsubsection{File {\it input/windx.sin\_y}} |
| 959 |
|
|
| 960 |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
The {\it input/windx.sin\_y} file specifies a two-dimensional ($x,y$) |
| 961 |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$. |
map of wind stress ,$\tau_{x}$, values. The units used are $Nm^{-2}$ (the |
| 962 |
Although $\tau_{x}$ is only a function of $y$n in this experiment |
default for MITgcm). |
| 963 |
|
Although $\tau_{x}$ is only a function of latitude, $y$, |
| 964 |
|
in this experiment |
| 965 |
this file must still define a complete two-dimensional map in order |
this file must still define a complete two-dimensional map in order |
| 966 |
to be compatible with the standard code for loading forcing fields |
to be compatible with the standard code for loading forcing fields |
| 967 |
in MITgcm. The included matlab program {\it input/gendata.m} gives a complete |
in MITgcm (routine {\it EXTERNAL\_FIELDS\_LOAD}. |
| 968 |
|
The included matlab program {\it input/gendata.m} gives a complete |
| 969 |
code for creating the {\it input/windx.sin\_y} file. |
code for creating the {\it input/windx.sin\_y} file. |
| 970 |
|
|
| 971 |
\subsubsection{File {\it input/topog.box}} |
\subsubsection{File {\it input/topog.box}} |
| 973 |
|
|
| 974 |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
The {\it input/topog.box} file specifies a two-dimensional ($x,y$) |
| 975 |
map of depth values. For this experiment values are either |
map of depth values. For this experiment values are either |
| 976 |
$0m$ or $-2000\,{\rm m}$, corresponding respectively to a wall or to deep |
$0~{\rm m}$ or $-2000\,{\rm m}$, corresponding respectively to a wall or to deep |
| 977 |
ocean. The file contains a raw binary stream of data that is enumerated |
ocean. The file contains a raw binary stream of data that is enumerated |
| 978 |
in the same way as standard MITgcm two-dimensional, horizontal arrays. |
in the same way as standard MITgcm two-dimensional, horizontal arrays. |
| 979 |
The included matlab program {\it input/gendata.m} gives a complete |
The included matlab program {\it input/gendata.m} gives a complete |
| 1034 |
\subsubsection{Code Download} |
\subsubsection{Code Download} |
| 1035 |
|
|
| 1036 |
In order to run the examples you must first download the code distribution. |
In order to run the examples you must first download the code distribution. |
| 1037 |
Instructions for downloading the code can be found in the Getting Started |
Instructions for downloading the code can be found in section |
| 1038 |
Guide \cite{MITgcm_Getting_Started}. |
\ref{sect:obtainingCode}. |
| 1039 |
|
|
| 1040 |
\subsubsection{Experiment Location} |
\subsubsection{Experiment Location} |
| 1041 |
|
|
| 1042 |
This example experiments is located under the release sub-directory |
This example experiments is located under the release sub-directory |
| 1043 |
|
|
| 1044 |
\vspace{5mm} |
\vspace{5mm} |
| 1045 |
{\it verification/exp1/ } |
{\it verification/exp2/ } |
| 1046 |
|
|
| 1047 |
\subsubsection{Running the Experiment} |
\subsubsection{Running the Experiment} |
| 1048 |
|
|
| 1061 |
% pwd |
% pwd |
| 1062 |
\end{verbatim} |
\end{verbatim} |
| 1063 |
|
|
| 1064 |
You shold see a response on the screen ending in |
You should see a response on the screen ending in |
| 1065 |
|
|
| 1066 |
{\it verification/exp1/input } |
{\it verification/exp2/input } |
| 1067 |
|
|
| 1068 |
|
|
| 1069 |
\item Run the genmake script to create the experiment {\it Makefile} |
\item Run the genmake script to create the experiment {\it Makefile} |