<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Saeid, I think that these were rhetorical questions.<div class=""><div class="">Oceanic eddies are not 12 degrees across and geostrophic eddies do</div><div class="">not generate dw/dt sufficiently large to warrant the "nonHydrostatic=.True.” flag.</div><div class="">If you want geostrophic eddies in your simulation, you need to configure</div><div class="">your simulation with 1/4-degree horizontal spacing or better (1/4-deg is marginal).</div><div class="">If you want to explore non-hydrostatic physics, your horizontal and</div><div class="">vertical grid spacing need to be of comparable order of magnitude, e.g., <~100 m.</div></div><div class=""><br class=""></div><div class="">Dimitris</div><div class=""><br class=""></div><div><blockquote type="cite" class=""><div class="">On Aug 15, 2017, at 10:16 AM, Saeid Esmaeilpour <<a href="mailto:saeidesmaeilpour@gmail.com" class="">saeidesmaeilpour@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div dir="ltr" class="">Yes they have.<div class=""><br class=""></div><div class="">Saeid</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Tue, Aug 15, 2017 at 1:14 PM, Jody Klymak <span dir="ltr" class=""><<a href="mailto:jklymak@uvic.ca" target="_blank" class="">jklymak@uvic.ca</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=""><br class="">
<br class="">
On 15 Aug 2017, at 9:58, Saeid Esmaeilpour wrote:<br class="">
<br class="">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Thanks again Jody,<br class="">
It was really helpful, for the last question about this issue, Do I need<br class="">
nonHydrostatic=.True. for the simulation of Eddies? Isn't that a fine-scale<br class="">
phenomena? will MIT show up Eddies at 2-degree resolution?<br class="">
</blockquote>
<br class=""></span>
Do your eddies have large dw/dt?<br class="">
<br class="">
Are they about 12-degrees across?<br class="">
<br class="">
Cheers, Jody<div class="HOEnZb"><div class="h5"><br class="">
<br class="">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br class="">
Thanks,<br class="">
Saeid<br class="">
<br class="">
On Tue, Aug 15, 2017 at 12:42 PM, Jody Klymak <<a href="mailto:jklymak@uvic.ca" target="_blank" class="">jklymak@uvic.ca</a>> wrote:<br class="">
<br class="">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 15 Aug 2017, at 9:29, Saeid Esmaeilpour wrote:<br class="">
<br class="">
Jody,<br class="">
my model is about The simulation of currents Circulation from surface to<br class="">
depth in indian Ocean, and I selected nonHydrostatic=.TRUE., cause I<br class="">
think the model resolve the Nonlinear terms with nonHydrastatic=True (am I<br class="">
wrong ?). If I select nonHydrastatic=True, in this case how much should I<br class="">
set for cg3MaxIters? and If select nonHydrastatic=False, how much for that?<br class="">
basically for the simulation of currents Circulation and at 2-degree I have<br class="">
to take non Hydraustatic=false?<br class="">
<br class="">
nonHydrostatic=.True. solves the non-hydrostatic equation for dw/dt,<br class="">
which essentially means the pressure needs to be determined globally from a<br class="">
Poisson equation, and hence the 3-D solver. .False. means that pressure<br class="">
is solved using the hydrostatic approximation (if you don’t know what this<br class="">
is, Google plus a basic GFD course would help).<br class="">
<br class="">
This really has nothing to do with non-linearity until you start resolving<br class="">
scales where the hydrostatic approximation breaks down (basically dw/dt is<br class="">
no longer << rho’g / rho_0).<br class="">
<br class="">
You really only need non-hydrostatic approximation for fine-scale runs<br class="">
looking at internal waves, dense overflows, convection, or other turbulent<br class="">
phenomena. None of which will show up at 2-degree resolution.<br class="">
<br class="">
Cheers, Jody<br class="">
<br class="">
Thanks again,<br class="">
Saeid<br class="">
<br class="">
On Tue, Aug 15, 2017 at 11:59 AM, Jody Klymak <<a href="mailto:jklymak@uvic.ca" target="_blank" class="">jklymak@uvic.ca</a>> wrote:<br class="">
<br class="">
Hi Saied,<br class="">
<br class="">
cg3dMaxIters is only used if nonHydrostatic=.True.. You aren’t resolving<br class="">
any non-hydrostatic physics at 2-degree resolution, so I would suggest<br class="">
setting nonHydrostatic=.False. Your model runs will be *much* faster.<br class="">
<br class="">
<br class="">
Cheers, Jody<br class="">
<br class="">
On 15 Aug 2017, at 8:43, Saeid Esmaeilpour wrote:<br class="">
<br class="">
Hi Dear users,<br class="">
could someone please explain to me what are the following PARM02?<br class="">
when I increase cg3dMaxIters from 50 to 400 (e.g,. cg3dMaxIters=400) the<br class="">
run speed becomes very slowly. how can I select this value? what's the<br class="">
criteria for selecting this number? My domain is 510*210 with 20layer and<br class="">
also my resolution is 2 degree (3704m).<br class="">
<br class="">
# Elliptic solver parameters<br class="">
&PARM02<br class="">
cg2dMaxIters=1000,<br class="">
cg2dTargetResidual=1.E-13,<br class="">
cg3dMaxIters=400,<br class="">
cg3dTargetResidual=1.E-13,<br class="">
<br class="">
Thanks for any help,<br class="">
Saeid<br class="">
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