chap_DIA.tex

The available ready-to-add diagnostics modules can be found in directory DIA.

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\subsection[Depth of various quantities (\textit{diahth.F90})]{Depth of various quantities (\protect\mdl{diahth})}

Among the available diagnostics the following ones are obtained when defining the \key{diahth} CPP key:

- the mixed layer depth (based on a density criterion \citep{de-boyer-montegut.madec.ea_JGR04}) (\mdl{diahth})

- the turbocline depth (based on a turbulent mixing coefficient criterion) (\mdl{diahth})

- the depth of the 20\deg{C} isotherm (\mdl{diahth})

- the depth of the thermocline (maximum of the vertical temperature gradient) (\mdl{diahth})

\begin{figure}[!t]
  \centering
  \includegraphics[width=0.66\textwidth]{DIA_mask_subasins}
  \caption[Decomposition of the World Ocean to compute transports as well as
  the meridional stream-function]{
    Decomposition of the World Ocean (here ORCA2) into sub-basin used in to
    compute the heat and salt transports as well as the meridional stream-function:
    Atlantic basin (red), Pacific basin (green),
    Indian basin (blue), Indo-Pacific basin (blue+green).
    Note that semi-enclosed seas (Red, Med and Baltic seas) as well as
    Hudson Bay are removed from the sub-basins.
    Note also that the Arctic Ocean has been split into Atlantic and
    Pacific basins along the North fold line.
  }
  \label{fig:DIA_mask_subasins}
\end{figure}

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\subsection[CMIP specific diagnostics (\textit{diaar5.F90}, \textit{diaptr.F90})]{CMIP specific diagnostics (\protect\mdl{diaar5})}

A series of diagnostics has been added in the \mdl{diaar5} and \mdl{diaptr}.
In \mdl{diaar5} they correspond to outputs that are required for AR5 simulations (CMIP5)
(see also \autoref{sec:DIA_steric} for one of them).
The module \mdl{diaar5} is active when one of the following outputs is required :
global total volume (voltot), global mean ssh (sshtot), global total mass (masstot), global mean temperature (temptot),
global mean ssh steric (sshsteric), global mean ssh thermosteric (sshthster), global mean salinity (saltot),
sea water pressure at sea floor (botpres), dynamic sea surface height (sshdyn).

In \mdl{diaptr} when \np[=.true.]{ln_diaptr}{ln\_diaptr}
(see the \nam{ptr}{ptr} namelist below) can be computed on-line the poleward heat and salt transports,
their advective and diffusive component, and the meriodional stream function .
When \np[=.true.]{ln_subbas}{ln\_subbas}, transports and stream function are computed for the Atlantic, Indian,
Pacific and Indo-Pacific Oceans (defined north of 30\deg{S}) as well as for the World Ocean.
The sub-basin decomposition requires an input file (\textit{subbasins}) which contains three 2D mask arrays,
the Indo-Pacific mask been deduced from the sum of the Indian and Pacific mask (\autoref{fig:DIA_mask_subasins}).

\begin{listing}
%  \nlst{namptr}
  \caption{\forcode{&namptr}}
  \label{lst:namptr}
\end{listing}

%% =================================================================================================
\subsection{25 hour mean output for tidal models}

\begin{listing}
  \nlst{nam_dia25h}
  \caption{\forcode{&nam_dia25h}}
  \label{lst:nam_dia25h}
\end{listing}

A module is available to compute a crudely detided M2 signal by obtaining a 25 hour mean.
The 25 hour mean is available for daily runs by summing up the 25 hourly instantananeous hourly values from
midnight at the start of the day to midight at the day end.
This diagnostic is actived with the logical $ln\_dia25h$.

%% =================================================================================================
\subsection{Courant numbers}

Courant numbers provide a theoretical indication of the model's numerical stability.
The advective Courant numbers can be calculated according to

\[
  C_u = |u|\frac{\rdt}{e_{1u}}, \quad C_v = |v|\frac{\rdt}{e_{2v}}, \quad C_w = |w|\frac{\rdt}{e_{3w}}
  % \label{eq:DIA_CFL}
\]

in the zonal, meridional and vertical directions respectively.
The vertical component is included although it is not strictly valid as the vertical velocity is calculated from
the continuity equation rather than as a prognostic variable.
Physically this represents the rate at which information is propogated across a grid cell.
Values greater than 1 indicate that information is propagated across more than one grid cell in a single time step.

The variables can be activated by setting the \np{nn_diacfl}{nn\_diacfl} namelist parameter to 1 in the \nam{ctl}{ctl} namelist.
The diagnostics will be written out to an ascii file named cfl\_diagnostics.ascii.
In this file the maximum value of $C_u$, $C_v$, and $C_w$ are printed at each timestep along with the coordinates of
where the maximum value occurs.
At the end of the model run the maximum value of $C_u$, $C_v$, and $C_w$ for the whole model run is printed along
with the coordinates of each.
The maximum values from the run are also copied to the ocean.output file.

\subinc{\input{../../global/epilogue}}

\end{document}