From guangyux at uw.edu Thu Jun 11 12:18:01 2026 From: guangyux at uw.edu (Guangyu Xu) Date: Thu, 11 Jun 2026 09:18:01 -0700 Subject: [MITgcm-support] numerical instability in a non-hydrostatic simulation Message-ID: Hello fellow MITgcm users, I have been running MITgcm simulations to investigate the wakes behind surface platforms. Attached are a plot of the vertical temperature cross-section from a non-hydrostatic run and the runtime model settings. The two vertical bars near 0 and 0.5 km w-e distances are the subsurface structures of two platforms. The initial temperature field is horizontally homogeneous. The model forcing consists of a constant eastward flow of 0.2 cm/s. There is no surface forcing or Coriolis. I noticed that the oscillations of isotherms around 0.5 km w-e distance have very short wavelengths, which span only two grid cells. These oscillations are numerical artifacts, and they are not present in the results of hydrostatic runs. I am interested to know if any of you have seen similar artifacts in non-hydrothermal simulations. Any suggestions on how to eliminate or reduce these numerical noises would be greatly appreciated. Many thanks! Guangyu -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: temp_ver_x_170400.png Type: image/png Size: 128189 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: data Type: application/octet-stream Size: 1401 bytes Desc: not available URL: From rajesh70530 at gmail.com Thu Jun 11 12:48:45 2026 From: rajesh70530 at gmail.com (Killampalli Rajesh) Date: Thu, 11 Jun 2026 22:18:45 +0530 Subject: [MITgcm-support] Question on Sequential Physics and Biogeochemistry Simulations in MITgcm Message-ID: Dear MITgcm Support, I am currently running MITgcm coupled with BLING or DARWIN, where the physical and biogeochemical components are integrated simultaneously. I would like to know whether it is possible to first run the physical model alone and then perform a separate biogeochemical simulation forced by the saved physical fields. Such a configuration would be useful for model tuning and sensitivity experiments, and could help reduce computational cost and simplify the simulation workflow. Could you please advise whether such a setup is available in MITgcm and point me to any relevant documentation? Thank you for your help. Best regards, Killampalli Rajesh Kind regards ``````````````````````````````````````````````` Killampalli Rajesh (Research Scholar) Centre For Atmospheric Sciences, Indian Institute of Technology, Delhi Hauz Khas, New Delhi - 110016 O-Email: asz238484 at iitd.ac.in P-Email: rajesh70530 at gmail.com Phone: +91 9492068095. ``````````````````````````````````````````````` -------------- next part -------------- An HTML attachment was scrubbed... URL: From mmanizza at ogs.it Thu Jun 11 13:09:11 2026 From: mmanizza at ogs.it (Manizza, Manfredi) Date: Thu, 11 Jun 2026 19:09:11 +0200 Subject: [MITgcm-support] Question on Sequential Physics and Biogeochemistry Simulations in MITgcm In-Reply-To: References: Message-ID: Hi Rajesh, I think these two links below can help you with global models with those two bgc packages to get familiar with coupled ocean phys-bgc modeling using MITgcm. But these are also on-line set ups. It seems you are more interested in off-line runs so it requires a bit more search and maybe somebody here can also provide more guidance from their own experience. I hope this helps to get you started though to understand how the coupling works in MITgcm. https://github.com/MITgcm-contrib/ecco_darwin/tree/master/v05/3deg https://github.com/MITgcm/MITgcm/tree/master/verification/global_oce_biogeo_bling Best of luck Manfredi Il giorno gio 11 giu 2026 alle ore 18:49 Killampalli Rajesh < rajesh70530 at gmail.com> ha scritto: > Dear MITgcm Support, > > I am currently running MITgcm coupled with BLING or DARWIN, where the > physical and biogeochemical components are integrated simultaneously. I > would like to know whether it is possible to first run the physical model > alone and then perform a separate biogeochemical simulation forced by the > saved physical fields. > > Such a configuration would be useful for model tuning and sensitivity > experiments, and could help reduce computational cost and simplify the > simulation workflow. > > Could you please advise whether such a setup is available in MITgcm and > point me to any relevant documentation? > > Thank you for your help. > > Best regards, > Killampalli Rajesh > > Kind regards > > > ``````````````````````````````````````````````` > > Killampalli Rajesh (Research Scholar) > > Centre For Atmospheric Sciences, > > Indian Institute of Technology, Delhi > > Hauz Khas, New Delhi - 110016 > > O-Email: asz238484 at iitd.ac.in > > > P-Email: rajesh70530 at gmail.com > > Phone: +91 9492068095. > ``````````````````````````````````````````````` > _______________________________________________ > MITgcm-support mailing list > MITgcm-support at mitgcm.org > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support > -------------- next part -------------- An HTML attachment was scrubbed... URL: From dmenemenlis at gmail.com Thu Jun 11 13:09:34 2026 From: dmenemenlis at gmail.com (Dimitris Menemenlis) Date: Thu, 11 Jun 2026 10:09:34 -0700 Subject: [MITgcm-support] Question on Sequential Physics and Biogeochemistry Simulations in MITgcm In-Reply-To: References: Message-ID: <2EA8CCE2-77CD-4E56-B2AD-4E83FD7B1B57@gmail.com> Yes, this capability does exist, see, e.g.,: https://mitgcm.readthedocs.io/en/latest/examples/cfc_offline/cfc_offline.html https://github.com/MITgcm/MITgcm/tree/master/verification/tutorial_cfc_offline but, I am not sure this will save you a lot of computation time. Depending on number of passive tracers that you carry forward, the frequency of your offline reads, and the speed of the I/O of your workstation, the gain in compute time could be negligible to negative. D. > On Jun 11, 2026, at 9:48?AM, Killampalli Rajesh wrote: > > Dear MITgcm Support, > I am currently running MITgcm coupled with BLING or DARWIN, where the physical and biogeochemical components are integrated simultaneously. I would like to know whether it is possible to first run the physical model alone and then perform a separate biogeochemical simulation forced by the saved physical fields. > Such a configuration would be useful for model tuning and sensitivity experiments, and could help reduce computational cost and simplify the simulation workflow. > Could you please advise whether such a setup is available in MITgcm and point me to any relevant documentation? > Thank you for your help. > Best regards, > Killampalli Rajesh > > Kind regards > > ``````````````````````````````````````````````` > Killampalli Rajesh (Research Scholar) > Centre For Atmospheric Sciences, > Indian Institute of Technology, Delhi > Hauz Khas, New Delhi - 110016 > O-Email: asz238484 at iitd.ac.in > P-Email: rajesh70530 at gmail.com > Phone: +91 9492068095. > ``````````````````````````````````````````````` > _______________________________________________ > MITgcm-support mailing list > MITgcm-support at mitgcm.org > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support