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Hi everyone,<br>
<br>
<p>Thanks a lot for your comments and help. Following your
recommendations, I’m attaching two figures and the namelists. </p>
<p>Fig1.jpg shows the MEDSEA parent model, with my domain marked by
a red rectangle, as well as the three points where I plotted the
SSH from the parent model.</p>
Fig2.jpg contains three subplots. The top panel corresponds to the
SouthWest of Sicily, where I compare the SSH at that point with and
without tides from the MEDSEA model. I also include the MEDSEA SSH
averaged over my domain (black line) shared in all plots and the
MITgcm output (my result) shown as a black dashed line. I repeat
this comparison in the south of my domain (cyan) and in Gibraltar
(red).<br>
<br>
Note: The Y-axis scales are not shared between subplots, but in all
cases, it's clear that the parent model shows a low frequency SSH
signal that I’m currently unable to reproduce in MITgcm.<br>
As you mentioned, probably I should disable the balanced flow
option. Additionally, I’m sharing the namelists data and data.obcs,
if you have any advice or suggestions, I’d be happy to try them.<br>
<br>
Thanks again for your help!<br>
Best regards,<br>
<p>Jordi</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 8/7/25 17:24, Martin Losch wrote:<br>
</div>
<blockquote type="cite"
cite="mid:45C12C69-2106-44E7-9A07-44252775F1BC@awi.de">
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Hi Jordi,
<div><br>
</div>
<div>it would help if you could provide your namelist files. And
maybe the customised *_OPTIONS.h files, if they are very
different from the standard ones.</div>
<div>Do you use open boundary conditions? Balanced flow is maybe
an issue?</div>
<div><br>
</div>
<div>Martin</div>
<div>
<div><br>
<blockquote type="cite">
<div>On 8. Jul 2025, at 16:57, Dimitris Menemenlis
<a class="moz-txt-link-rfc2396E" href="mailto:dmenemenlis@gmail.com"><dmenemenlis@gmail.com></a> wrote:</div>
<br class="Apple-interchange-newline">
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content="text/html; charset=UTF-8">
<div
style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Hi
Jodi, perhaps a good place to start would be to
understand cause of the larger oscillations in MEDSEA
and ROMS, which might then help you diagnose what is
missing in your MITgcm configuration. For example, if
the ~10-day oscillation in MEDSEA and ROMS is primarily
caused by transport through Gibraltar Strait, then you
could look at MITgcm’s transport through Gibraltar
Strait to see whether it has been correctly prescribed.
<div><br>
</div>
<div>D.<br id="lineBreakAtBeginningOfMessage">
<div><br>
<blockquote type="cite">
<div>On Jul 8, 2025, at 6:13 AM, Jordi Iglesias
<a class="moz-txt-link-rfc2396E" href="mailto:jiglesias@icm.csic.es"><jiglesias@icm.csic.es></a> wrote:</div>
<br class="Apple-interchange-newline">
<div>
<div style="padding-bottom: 1px;">
<p>Dear MITgcm community,<br>
<br>
Over the past few months, I’ve been
struggling to achieve realistic sea surface
height ("Eta") results in my MITgcm
simulations. I’ve tried several
configurations,including non-hydrostatic,
quasi-non-hydrostatic, and nonlinear free
surface options, but the SSH output often
differs significantly from the parent model
(the Copernicus Mediterranean analysis,
MEDSEA). I’ve attached an example and also
shared a link to illustrate the issue. I
have tides configured, and the ssh is
initialized from MEDSEA data. However, when
I compare the SSH output with the parent
model (or with a ROMS simulation, for
example), it appears to oscillate around a
constant value that doesn’t evolve much over
time, or changes are very small.<br>
<br>
A summary of my configuration: Horizontal
resolution: 1.6 km, NW Mediterranean Sea,
Atmospheric forcing: ECMWF, initial ssh set
with pSurfInitFile, SphericalPolarGrid,
quasiHydrostatic = .TRUE., nonlinFreeSurf =
3, rigidLid = .FALSE., implicitFreeSurface =
.TRUE., <br>
</p>
<p>If any additional parameters would help
diagnose the issue, I’d be happy to provide
them.<br>
<br>
The temperature, salinity, and velocity
fields are generally in good agreement with
ROMS and MEDSEA, but I’d really like to
improve the SSH performance. Has anyone
encountered a similar issue or found
strategies to improve SSH in MITgcm?<br>
<br>
Thanks in advance for your help!<br>
<br>
Best regards,<br>
Jordi<br>
<br>
<a class="moz-txt-link-freetext"
href="https://saco.csic.es/s/c2fSgN5RWPRcDSQ" moz-do-not-send="true">https://saco.csic.es/s/c2fSgN5RWPRcDSQ</a><br>
</p>
<p><br>
</p>
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