vertical mixing

[logvinov]

Hi All,

I am looking at the case of downwelling favorable wind driven flow in the domain with the sloping bottom.

This leads to an advection of lighter fluid beneath heavier fluid.

Could anybody tell me if there are any special tools in ROMS to intensify mixing in regions of unstable stratification?

Thanks a lot,
Evgeny

[kate]

Which vertical mixing scheme are you using? I believe all the non-trivial ones do this - LMD_MIXING, GLS_MIXING, MY25_MIXING, etc.

[logvinov]

Hi Kate,
Thanks for your reply.
I am using ana_vmix. And so far I keep constant value of AKt everywhere in the domain. T do that to keep theory simple. And it was good enough for the flat bottom domain.

Now I added sloping bottom to the problem. Due to the downwelling favorable wind advection of the lighter fluid beneath heavier fluid occur.
And I am trying to figure out how to deal with it. I was thinking about setting somehow increased mixing in those regions.


Thanks,
Evgeny

[wilkin]

If you keep a simple fixed analytical form for AKt then the model has no way to address the static instability of the water column when light water pushes beneath the heavy. In reality, the instability drives convective overturn which you must parameterize with a greatly enhanced vertical mixing.

You have to activate one of the turbulence closure options (LMD, MY25 or GLS MIXING) to pose this problem sensibly.