[MITgcm-support] Buoyancy anomaly

[Christopher L. Wolfe]

Even if the model is hydrostatic, buoyancy inversions will drive 
(grid-scale) hydrostatic convection if the model is finely resolved 
enough. You may still get small regions of negative stratification near 
the surface if you have surface cooling. In fact, you *have* to have 
negative stratification near the surface if you are cooling the surface 
since the surface heat flux is proportional T_z (the fact that MITgcm 
uses relaxation instead of true surface flux complicates things, but 
doesn't change the basic result.)

I'm having a little trouble interpreting your plots, so I can't tell if 
your regions of negative stratification are unreasonably large or 
strong, but I get regions of negative stratification extending down to 
about 100 m in my models representation of the ACC.

Christopher

-----------------------------------------------------------
Dr. Christopher L. Wolfe             		 858-534-4560
Physical Oceanography Research Division    OAR 357
Scripps Institution of Oceanography, UCSD  clwolfe at ucsd.edu
-----------------------------------------------------------

On Mar 21, 2007, at 4:31 AM, Laure Grignon wrote:

>
> Hello,
> Do you use a hydrostatic or non-hydrostatic configuration? If 
> hydrostatic,
> you’ll need to parameterise these effects (p232 of the MIT manual, on 
> ocean
> convection, for the simplest ways of doing it).
> If you've already done this, I don't know...
> Laure
>
>
>
>
> On 21/3/07 11:03, "Yi HanSoo" <yi.hansoo at gmail.com> wrote:
>
>> Hi MITgcm users
>>
>> From the results of my model run, I have a question on how to 
>> interpret the
>> buoyancy anomaly.
>> In the modeing, I used linear equation of state and set the salinity 
>> to zero.
>> So the density is only function of temperature here.
>> And I got the hourly averaged "Rhoanoma (=rho-rhoConst(=999.8 kg/m^3 
>> in my
>> run))" from the diagnostic pkg.
>> As attached, they are time-depth plot of temperature profile and 
>> buoyancy
>> anomaly at certain point in the domain
>> and I just don't understand the density profile from this figure.
>> Denser water lay over the less denser water and doesn't sink down as 
>> time
>> evolves, weird right ?.
>> Can anyone give me an idea on how to interpret this result and Is 
>> there
>> something that I have to mind in the modeling?
>>
>> Thanks in advance.
>>
>> Lee
>
>
>
>
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