[MITgcm-support] Stratification creating current without forcing (Martin Losch)

[Martin Losch]

Hi Michael,

that’s a good point, I just modified verification/isomip/input/ a little to have a linear salinity profile (and adjusted the  SHELFICEloadAnomalyFile), and I too get increasing kinetic energy (ke_mean=5e-13m^2/s^2 after 20 timestep and still increasing exponentially). When I turn off diffusion, then the ke_mean rises only to 1e-22m^2/s^2 due to the not quite perfect loadAnaomaly and then goes back to 1e-23m^2/s^2 aby timestep 20. I keep forgetting that (vertical) diffusion is actually a source of energy in a stratified fluid.

Martin

> On 28. Nov 2019, at 15:11, Michael Spall <mspall at whoi.edu> wrote:
> 
> Hi Nadine,
> This may result from diffusion and the no-flux into the bottom. This
> forces the isopycnals to be perpendicular to the topography which,
> for a sloping bottom gives rise to pressure gradients and a geostrophic
> flow. I found something similar in the past.
> 
> Mike
> 
> Sent from my iPad
> 
>> On Nov 28, 2019, at 6:00 AM, Martin Losch <Martin.Losch at awi.de> wrote:
>> 
>> Hi Nadine,
>> 
>> this is weird, can you make your configuration available, so I can run it? I guess a coarse grained version would be enough? (code directory, and input directory with bathymetry, etc, and startification, please don’t post the files to this list, but rather a link).
>> 
>> Martin
>> 
>>> On 28. Nov 2019, at 10:42, Nadine Steiger <Nadine.Steiger at uib.no> wrote:
>>> 
>>> Hi,
>>> 
>>> salinity does not go below or above the initial values.
>>> 
>>> When creating the hydrogSaltFile, I precribe the salinity everywhere, as I figured that MITgcm masks the topography during initialization.
>>> 
>>> I tried to prescribe salinity through hydrogSaltFile and through sRefFile, but I get the same issue in both cases.
>>> 
>>> When I turn off saltStepping and saltAdvection, the ocean stays in rest.
>>> 
>>> When I use a flat bottom instead of a channel, the problem does not occur either.
>>> 
>>> Nadine
>>> 
>>> 
>>> -- 
>>> Nadine Steiger
>>> PhD Candidate
>>> University of Bergen | Geophysical Institute
>>> Bjerknes Centre for Climate Research
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>> 
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