NEMO: Ticket #1350: dev CNRS-0 --- new version of tranpc (non-penetrative convection) based local stability
http://forge.ipsl.jussieu.fr/nemo/ticket/1350
<p>
npc, the non-penetrative convection algorithm, has been designed to restore the static stability of the water column at each model time step (Madec et al. JPO 1991). Its implementation in OPA was using potential density to calculate the static stability, a limitation of the algorithm that make it useless when using a full equation of state. In addition, the passage from OPA8 (Fortran 77) to OPA9 (NEMO, Fortran 90) introduces bugs in the algorithm that haven't been fixed (see <a class="priority_is_low closed ticket" href="http://forge.ipsl.jussieu.fr/nemo/ticket/1092" title="Defect: non-penetrative convection option does not work (closed: fixed)">#1092</a>, <a class="priority_is_low closed ticket" href="http://forge.ipsl.jussieu.fr/nemo/ticket/1326" title="Bug: weird loop in tra_npc (closed: wontfix)">#1326</a>).
</p>
<p>
Here, a new version of the algorithm has been developed. It is based on the same principle as the original one, but is now able to handle any equation of state (i.e. working on locally computed Brunt-Vaisala frequency). To that purpose, the algorithm is now using alpha and beta (thermal expansion and haline contraction coeff.) to compute the stability of the water column instead of gradient of potential density.
</p>
<p>
The algorithm has been implemented by Laurent Brodeau (brodeau@…).
He intensively tested in ORCA2-LIM2 and ORCA1-LIM2 configurations.
</p>
<p>
The new algorithm has 2 main properties :
</p>
<blockquote>
<p>
1- it is designed for any equation of state
2- it is working !
</p>
</blockquote>
<p>
Note that since the algorithm is using alpha and beta, it is usable only in the new TEOS10 branche (see <a class="priority_is_normal closed ticket" href="http://forge.ipsl.jussieu.fr/nemo/ticket/1294" title="Task: dev CNRS-1 & CNRS-10 --- TEOS10 and Energy diag. (closed: fixed)">#1294</a>).
</p>
en-usNEMOhttp://forge.ipsl.jussieu.fr/nemo/chrome/site/logos/NEMO_blue.png
http://forge.ipsl.jussieu.fr/nemo/ticket/1350
Trac 1.0.1lovatoThu, 07 Sep 2017 14:17:55 GMTstatus changed; resolution set
http://forge.ipsl.jussieu.fr/nemo/ticket/1350#comment:1
http://forge.ipsl.jussieu.fr/nemo/ticket/1350#comment:1
<ul>
<li><strong>status</strong>
changed from <em>new</em> to <em>closed</em>
</li>
<li><strong>resolution</strong>
set to <em>fixed</em>
</li>
</ul>
<p>
The developments of this ticket are included in the NEMO V3.6_stable (<a class="changeset" href="http://forge.ipsl.jussieu.fr/nemo/changeset/5550" title="">r5550</a>) and trunk (<a class="changeset" href="http://forge.ipsl.jussieu.fr/nemo/changeset/5386" title="#1092 minor bug correction on tranpc.F90 algorithm ">r5386</a>).
</p>
Ticket