[MITgcm-support] numerical instability in a non-hydrostatic simulation

[Guangyu Xu]

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
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